When you buy a furnace or heat pump, you're making a 15-20 year bet on fuel costs. That's how long well installed equipment lasts. If you choose a hybrid system — a two-way AC (heat pump) paired with a gas furnace — you get fuel choice. If gas stays cheap, lean on the furnace. If gas spikes, lean on the heat pump. Both go crazy? Install solar and make your own electricity. You don't have to predict the future. You just have to not get locked into a fuel you have zero control over.

I know this because I tried to predict gas prices in the past. I was mostly right about the direction and mostly wrong about the timing. Here's the story, and why it matters if you're buying HVAC in the next few years.

The Predictions
In 2012, I was 34 and running an insulation company in Cleveland. Gas prices had recently spiked — they'd been very expensive through much of 2005-2008, and I was (idiotically) talking to homeowners about payback periods for insulation at those prices. I wasn't an energy analyst. I was a guy who read a lot and could do basic math.

I wrote a blog post called "Why Your Gas Bill May Triple in the Next 5 Years." I cockily called one section "Margins Like a Drug Cartel" — because Asian wholesale natural gas was $20/MMBtu while US prices were $2/MMBtu. A 10:1 ratio. I listed five reasons prices were headed up: electricity generation switching to gas, vehicle fleets converting, well owners capping wells because they were losing money at $2, exports coming online, and growing demand from China and India.

Did I predict $12/mcf retail within five years? I did. What an idiot. My natural gas export terminal timeline: 2015-2016.

In 2014, I followed up with "Oil Is Dead, and It's No Big Deal", where I wrote about Russia threatening Europe's gas supply and predicted we'd have "world priced natural gas in the near future, which could be 2-8 times more than we are paying now." The 2-8x framing left some room. The "near future" part... did not.

I said five years. It took twelve. The export terminals came online in 2016 — which was technically in my predicted range — but prices didn't respond the way I expected.[^1]

Math wins, but it takes longer than it should.

What Actually Happened
The first LNG export cargo left Sabine Pass, Louisiana on February 24, 2016. By 2023, the US was the largest LNG exporter in the world. By 2025, we were shipping 15 billion cubic feet per day overseas — more gas than all 74 million American households on the gas network consume combined.[^2]

Russia did exactly what I worried about in 2014. They invaded Ukraine in 2022, Europe panicked, and suddenly every available LNG cargo was headed to Rotterdam instead of Tokyo. Henry Hub tripled from its 2020 low of $2.03 to an annual average of $6.45 in 2022 — and peaked at $9.68 in August of that year.[^3] That 10:1 ratio I wrote about in 2012 compressed violently and fast.

Prices came back down in 2023 and 2024 — so far down that 2024 set a record low at $2.20. People forgot. They always forget.

What About Iran?

But the structural problem I identified in 2012 hasn't gone away. The Iran conflict is going on as I write this and while US Henry Hub prices haven't spiked too much yet because of US production capability, but 17% of world LNG exports are offline, so what will come of that as we hit winter usage later this year?

Winter future prices are expected to be 50-70% higher than they are right now. Aince the US is able to export more and more to the world, we're likely to be tied more tightly to world prices as we've seen since 2016, that article and a number of other sources say the same thing.  

Bottom Line

Relying on gas, propane, or oil for heating alone is likely to be more expensive during the 15-20 year lifespan of your new HVAC system. 

Let's look at some data:

Where We Are Now

Eight LNG export terminals are operating in the US. Another 24 billion cubic feet per day of capacity is under construction or approved. If all of it gets built, US export capacity will hit 35 billion cubic feet per day — roughly a third of everything we produce.[^4]

The EIA is now saying the quiet part out loud: "Higher natural gas prices in 2025 and 2026 are the result of strong export growth that persistently outpaces U.S. natural gas production."[^5] Henry Hub is forecast around $3.80-$4.00 for 2026.

And exports aren't the only new mouth to feed. Data centers for AI are adding billions of cubic feet of daily gas demand. PJM — the grid operator for 13 eastern states — has greenlit 50+ new gas-fired power plants to meet data center load. The electric power sector already consumes more natural gas than all US homes and businesses combined — about 36 billion cubic feet per day.[^6]

More LNG terminals. More data centers. Production can grow to meet it — shale wells can be drilled fast — but they also decline fast. Shale wells spike when first drilled and fall off steeply, so you're on a treadmill: you have to keep drilling just to stay flat. The EIA is projecting production growth, but they're also projecting that demand growth outpaces it.[^7]

A Two-Way AC Hedges Your Bet

This is the part that matters if you're buying HVAC equipment: A two-way AC hedges your bet. If gas stays cheap, you haven't lost much. If gas doubles over the next decade — which is what the trendlines suggest — you've dodged a bullet. And if you pair it with solar, you've taken yourself out of the global commodity casino entirely.

Your natural gas bill is no longer set by US supply and demand alone. It's increasingly influenced by cold winters in Europe, economic growth in China, wars in the Middle East, and how many data centers get built in Virginia. Electricity prices aren't immune — gas sets the marginal price in many power markets. But electricity has something gas doesn't: you can make your own. A solar array locks in your energy cost for 25 years. Try doing that with natural gas.

Where I Might Be Wrong (Again)

There's a massive wave of new LNG export capacity coming online worldwide between 2026 and 2028 — the largest in the industry's history. IEEFA projects that global supply capacity could exceed demand scenarios through 2050.[^8] If that capacity hits faster than demand grows, we could see a temporary glut that pushes prices down in 2027-2028. Some analysts project spot prices falling back to $7-8/MMBtu in Europe and Asia by 2029.[^9]
US shale production has also been remarkably responsive to price signals. When prices spiked in 2022, producers drilled more. When prices crashed in 2024, they pulled back. That flexibility has kept domestic prices lower than many people (including me) expected.

So I might be wrong again on timing. Maybe cheap gas has another run in it. But the hybrid argument holds regardless. A two-way AC doesn't cost much more than a one-way AC, and it gives you fuel choice no matter what gas prices do. It's the right bet even if gas stays cheap — and it's a lifesaver if it doesn't.

The Lesson

I was early in 2012. Being early in markets is the same as being wrong, except you get to be smug about it later. Or just feel dumb. Or both. 

But the direction hasn't changed. The US is connecting its domestic gas market to world prices, permanently, through concrete and steel terminals that will operate for 25+ years. Every new terminal ratchets the connection tighter. Every new data center adds demand. The macro trend looks more likely to go up than down.

In 2012 I closed with "these ARE the good old days" for cheap natural gas. Fourteen years later, $2 gas came back one more time in 2024 — a gift from mild weather and overproduction. I don't think we'll see it again.
Math wins. It just takes longer than it should.

Nate Adams is a building scientist and author of Common Sense HVAC, a homeowner's guide to getting a quality HVAC installation. He lives near the New River Gorge in West Virginia, where his gas bill is mercifully low — because he heats with a heat pump.

Sources:
[^1]: US LNG exports grew from 0.5 Bcf/d in 2016 to 15.0 Bcf/d in 2025. EIA, "Ten years after first Sabine Pass cargo," Feb 2026. [^2]: Canary Media, "The US is exporting huge amounts of natural gas," Feb 2026. [^3]: Henry Hub annual averages: $2.03 (2020), $3.89 (2021), $6.45 (2022), $2.57 (2023), $2.20 (2024). EIA Natural Gas Monthly. [^4]: FERC estimates 35 Bcf/d of total US LNG export capacity (14.6 existing + 23.7 under construction + 11.4 approved). American Action Forum, March 2026. [^5]: EIA Short-Term Energy Outlook, Jan 2025. [^6]: US electric power sector consumed 35.8 Bcf/d in 2025 (39% of total). Residential + commercial combined: ~22 Bcf/d. EIA, "Electric sector gas use fell 3% in 2025," March 2026. [^7]: EIA Short-Term Energy Outlook, March 2026. [^8]: IEEFA, "Global LNG Outlook 2024-2028." [^9]: Oxford Institute for Energy Studies, "A New Global Gas Order? Part 1," July 2023.

I spent some time mapping which residential energy code every state is on right now after my friend Glenn T Remington asked about what energy codes each state was on. 

Then I posted it on social media and got corrected within the hour — four states wrong, several more out of date. So I spent a bit more time verifying every state against five different databases, discovered the databases disagree with each other, and learned more about energy codes than 15 years in HVAC ever taught me. What started as both curiosity and a question from my friend Glenn T Remington on LinkedIn took me down a rabbit hole I wasn’t expecting.
The result is an interactive map you can hover over to see your state’s status, including whether blower door testing and duct leakage testing are required on new homes.
The short answer for most of you: maybe on paper, probably not in practice.

The IECC — the code your new home was (probably) built to

Almost every state bases its residential energy code on the International Energy Conservation Code, or IECC. It gets updated every three years — 2006, 2009, 2012, 2015, 2018, 2021, 2024. Each edition gets a little tighter on insulation, air sealing, and duct leakage.
Here’s the problem: states adopt these codes on wildly different timelines. Right now in 2026, the spread looks like this:

• Rhode Island, New York, Illinois, Nevada, and North Dakota are on the 2024 IECC — the newest and tightest.
• Most of the Northeast, plus states like Michigan, Nebraska, Wisconsin, and Utah are on the 2021 IECC.
• A chunk of the Midwest and South is still on the 2015 or 2018 IECC.
• Oklahoma is on the 2006 IECC. That’s twenty years old. No blower door test. No duct testing. Minimal insulation standards.
• Seven states have no mandatory statewide residential energy code at all.

My own state of West Virginia? We’re on the 2009 IECC. The legislature passed a bill in 2022 to update to the 2015 code, but it never effectively went through. And honestly, even the 2009 code barely gets enforced outside the larger cities. Sometimes being 30 years behind has its charm — handshakes still mean something here. Sometimes it doesn’t.

Why blower door and duct leakage testing matter

Here’s what I really want you to understand: the code edition matters less than whether your state actually requires testing — because testing is how you know the house was well built.

The 2012 IECC was the first edition to require a mandatory blower door test on every new home — no visual inspection alternative. That was a big deal. It meant someone had to show up with equipment and prove the house didn’t leak like a sieve.

But here’s what happened: states adopted the 2012+ codes and then amended out the teeth. Indiana adopted the 2018 code but lets builders do a visual inspection instead of an actual test. Louisiana adopted the 2021 code but loosened the air leakage limit to 7 ACH50 — which is like saying your house can leak, just not catastrophically. Idaho raised the threshold to 5 ACH50 and allows sampling instead of testing every home.

Duct leakage testing has the same problem, with an added twist. From 2009 through 2018, if all your ductwork was inside the thermal envelope — meaning inside conditioned space — no duct blaster test was required. The 2021 IECC finally closed that loophole. But plenty of states haven’t gotten to 2021 yet, and even on the states that have, enforcement varies by jurisdiction.

The sources don’t agree with each other

This was the part I didn’t expect.
I cross-referenced BCAP, ACEEE, NAHB, NEEP, and DOE’s Building Energy Codes Program. They disagree on a surprising number of states. BCAP’s entry for Iowa showed Indiana’s data — a straight copy-paste error. BCAP listed Kentucky at 2015 IECC, but that’s the building code version; the energy provisions actually reference the 2009 IECC. Eric George, who builds houses in Kentucky, knew this instantly.
William Parlapiano, who tracked this stuff painstakingly for Knauf before he retired, told me roughly 60% of states amend their adopted codes — very few adopt as-is. He pointed me to the Regional Energy Efficiency Organizations (REEOs) as the most reliable source. The six REEOs — NEEP, SEEA, MEEA, SWEEP, SPEER, and NEEA — cover 46 states and are genuinely on the ground watching code adoption happen in real time. They were the best source I found.
The lesson: no single database has it right for all 50 states. You have to cross-reference, and even then you might be wrong. Which is why the crowd-sourced corrections turned out to be the most reliable data of all.

The gap between “adopted” and “enforced”

This is the part that should make you uncomfortable if you’re building or buying a new home. “Adopted” and “enforced” are not the same thing. Ohio technically requires 3 ACH50 on new homes, but outside the major cities, good luck finding an inspector who owns a blower door.
And it’s getting worse in some places. Missouri has a bill that would prevent local jurisdictions from adopting anything more stringent than the 2009 IECC. Washington has a bill to freeze code updates for a decade. North Carolina froze its residential code in 2023.

This isn’t just inertia. It’s organized pushback — some of it genuine concern about housing costs, some of it builder lobbying against any standard that requires testing and verification.

What you should actually do

Forget the map for a minute. Here’s the most useful thing I can tell you:
Call your local building department and ask two questions. First: “Do you require a blower door test on new residential construction, and what’s the ACH50 limit?” Second: “Do you require a duct leakage test, and what’s the CFM25 limit?”
Those two answers tell you more about the quality of new construction in your area than any color-coded map ever will. And if they can’t answer clearly? That tells you something too.

The map DOE already built

​After all this work, I discovered the Department of Energy already has something better than what I was trying to build. Their Building Energy Codes Program doesn’t just track which edition each state adopted — they model the actual energy use of each state’s code, including all the amendments, and compute what the code is functionally equivalent to. A state that claims the 2021 IECC but gutted it with weakening amendments shows up at its true performance level, not its label.

You can explore it yourself on DOE’s interactive dashboard, or download the raw state-level data from energycodes.gov. This is ultimately what I was trying to understand — not just what’s on the books, but what’s actually in effect.
The interactive mapI’ve published a full interactive map with state-by-state details, blower door requirements, duct testing requirements, per-state sources, and all the footnotes and caveats. Check it out and see where your state stands.
Because the HVAC system in your new home is only as good as the code that’s actually enforced — and the contractor who actually follows it.

Corrections & contributors

This map started rough and got better because people spoke up:

• Daniel Baur-McGuire — Iowa correction (2012 IECC, not 2018)
• Eric George — Kentucky correction (2009 IECC for residential, not 2015)
• Noah Lawrence — New York update (2024 IECC via 2025 ECCCNYS)
• Linda Toth — Virginia correction (2021 IECC)
• Timothy Kisner — Texas detail (the IRC/IECC/ERI compliance path breakdown)
• William Parlapiano — The REEOs recommendation and the reality check on amendments that became the thesis of this whole piece
• Ken Zemach — The enforcement comment that started everything: “If inspectors actually held builders accountable to the energy code from years ago, most houses would be way better already.”

If you see something wrong, tell me. I’ll verify it and update. This is a living document.

​
Nate Adams is a building scientist and author of Common Sense HVAC, a homeowner’s guide to getting a quality HVAC installation. He lives near the New River Gorge in West Virginia.

We have 4 all electric homes in southern WV near the New River Gorge National Park.

We just experienced a particularly cold winter, so I was curious to see how much heating our houses cost us. They have good heat pumps, but none of them have what I consider to be good insulation and air sealing. 

I was happy to see the TOTAL monthly cost was in the $600-700 range, pretty remarkable. Thermostats were set to 68-70F, electric cost is $.18/kwh. 

​Considering this felt like a full Cleveland winter where I lived for 43 years, this seems like getting off easy!

You can see all of our themed short term rentals at appalachianescapes.net 

Here's the weather from those two months:​

In 2019 we made the very hard decision to sell one of the coolest homes I've been in and the coolest house we've ever owned, an 1835 former general store in Mantua Ohio. 

While a lot of this decision was financial, a big chunk of it was because the house was so hard to electrify. If it had had duct work, I could have simply installed a hybrid/dual fuel system (a furnace plus a heat pump) and moved on. Hybrids are the far simpler path, but this house does let us look at boiler heated homes and some of the options for those.

I'll give the background on the house, the 3 plans I considered, and how these lessons apply at a broader scale. 

Home Background

When my wife was young and her family was driving to the St Joseph's Ox Roast Festival in Mantua, they'd often pass this 1835 home and she'd say "someday I'd love to have a house like that but I'll never be able to afford it." We bought it when she was 25 and through hard work paid it off when she was 28 (until we hocked it in again...) It was literally a dream come true. 

The house was a HUD foreclosure which are normally the worst of the worst, but this house was in remarkably good shape. We went from not thinking about moving on Friday to having an auction offer accepted on Monday. It was a wild ride! We bought it in early 2010, my wife and I lost both our jobs in 2009 with the housing crash, so we couldn't get a loan because we didn't have 2 years of self employed tax returns. Her parents were kind enough to help us buy it.

This house was the general store for the town of Mantua until 1855 when the train line was put in 3 miles south and downtown moved. It's now on a quaint little aborted New England town square complete with a church, a historical society, and a town hall. We lived there for 9 years, our daughter was born there, and we expected to spend most of our lives there.

I became a House Whisperer while living there thanks to the mentorship of my old partner Ted Kidd. It became really clear to me that heat pumps were the best way to create a healthy and comfortable home.

I began to help clients electrify their homes, removing my first client gas meter in 2014. Naturally I started looking at my own home, and found it was one of the hardest homes I'd looked at to electrify.

Then my wife started listening to the ChooseFI podcast. FI stands for Financial Independence, basically you save up enough so you can semi-retire early and do whatever you want day to day. We've always been financially conservative, but we'd had a fairly tough road in our careers until then. We knew we were behind on retirement savings, so we decided to sell the house, buy a fixer upper, and put the balance in the market.

Portage County Ohio was not an expensive housing market in 2019, $100/square foot was pretty common outside of high end suburbs. It's now about double that. 

The house is 2200 square feet above ground plus about 750 square feet of finished basement. The house had been lifted to put a 12 course modern foundation underneath it, not the terrifying old cellar you'd expect.

We sold the house in November 2019 for $200K which will give perspective on the packages I considered. If this were a $1 million home, the decision matrix would have been different.

High Heating Load, No Ducts, and the Wrong Radiators

One of the biggest challenges was how much this house takes to heat. My former partner Ted Kidd and I are fastidious about doing accurate heating load calculations and truing them to actual energy use. I found that in Cleveland every 300 therms of natural gas use works out to roughly a ton of heating load. This house used 1500-1800 therms/year, so that's a 5-6 ton heat load or 60,000-72,000 btus. That matched our detailed load calc.

A heat load that high basically requires two heat pump systems to do since the most common sizes are 2 and 3 tons (24,000 and 36,000 btus.) The house has no duct work, so those systems would need to be installed as well, or run ductless units which is not my favorite.

If the load calculation were done by a traditional contractor, they would likely come up with 120,000-150,000 btus, over double what reality is and likely preventing a heat pump. I've consistently found that the US industry standard Manual J load calculation comes up with numbers that are around double what's actually needed, especially if you don't know how leaky the house is (tested with a blower door.)

Being a historic home and already having a reasonable blower door of 3800 cfm50, (under a 2:1 leakage to square footage ratio is well below average for a house this age), and not really wanting to dig into the siding & windows, there really wasn't much I could do to improve the heating load. 

The house also has a hot water boiler system (as opposed to steam) that uses low mass Slant Fin radiators. There's very little water or mass in this type of radiator, so you have to run hotter water in them than you do with large, heavy, and voluminous cast iron radiators. The radiators were built pretty nicely into the baseboards, so I didn't really want to change them to cast iron radiators. 

I tested how low I could turn the water down to on a 5F heating design day, it was between 170-180F. This means that I can't easily use an air to water heat pump because in general they max out at 150F and that comes with a significant efficiency penalty. They are most efficient in the 90-120F range which wasn't possible on this home.

This meant that changing the boiler out was not an easy option.

The house also didn't have AC, although you may be surprised that I could cool it with only two 5,000 btu window ACs. One upstairs and one downstairs. I had to plan ahead, if there was a 90 degree day coming I needed to close the house up 48 hours in advance and crank the temperature down which drove my wife nuts, she shivered every time I did it. 

The basement is finished and the drywall ceiling is only 7' high, I can touch it by reaching up and I'm only 5'8". So adding duct work and killing another foot of ceiling height is not ideal, but it's also the best way to heat and cool half of the first floor. There also isn't a great way to run a duct from the first floor to the second floor so I can either use one system or put the second system in the basement and run it upstairs.

To summarize the challenges, the house has a high heating load, the wrong radiators for low temperature operation, no duct work, and a finished basement with a fairly low ceiling. This is a hard one.

So what could I do to this house?

Never Half @ss Things: Three Plans

I mulled different ways to electrify this house and came up with three plans that reference one of my dad's favorite sayings, "Never half-ass something when you can do it right." I came up with half @ss, reasonable but effective, and whole @ass plans.

Half @ss: $40-70K

• Ductless heat pump in the 750 sf living room area
• Ductless heat pump in the basement
• Ducted mini split heat pump in the kitchen/office/laundry area
• Ducted mini split heat pump in the attic to serve the bedrooms separately
• Santa Fe XT155 ventilating dehumidifier with mini duct system to basement and first floor
• Maybe spray foam the top attic so the heat pump for the second floor would be in conditioned space

To be frank, this plan pretty much just ticks me off. Ductless mini splits only kinda do one of the 6 Functions of HVAC well: load matching. Load matching is when the HVAC matches exactly as much heating or cooling output as is required by the house at that moment, it's a requirement for true comfort. They aren't good at filtration, dehumidification, fresh air, mixing, or humidification. I hate how much compromise is involved here. The ventilating dehu is an attempt to take some of the edge off of this, as I could hook it to one of the two small ducted systems and provide better filtration, dehumidification, and fresh air. 

The attic has a decent air seal and R-60 cellulose in it, which is pretty good. But if you're going to put a ducted system in, it's by far the best to bring it into an enclosed space, which means sucking out all of that cellulose, the fiberglass batts under it, and installing closed cell spray foam on the roof deck. This is pretty easily a $20K project. 

But with a likely sale price of $200K, this also wasn't going so far into the house that I was setting back retirement that far. But spending this much money knowing I'd kick myself seemed dumb. So what's next?

Reasonable But Effective: $80-100K

• Carrier GreenSpeed heat pump in Common Sense HVAC configuration with new duct system in the second story attic to run the second floor and maybe part of the first floor below it
• Carrier GreenSpeed heat pump in Common Sense HVAC configuration with new duct system to run the basement and part or all of the first floor (I'd need a room by room Manual D report to decide)
• Encapsulate the second floor attic by removing all the insulation and spray foaming the roof deck

This plan at least delivers the 6 Functions of HVAC well (read the free HVAC 101 chapter of The Home Comfort Book or the upcoming Common Sense HVAC Guide for more on what those are), so I'm not compromising nearly as much.

I'm also giving the upstairs heat pump a nice place to live, and I'd pick up some storage space in that attic, not that this house needed any more.  

But now I've spent about half the value of the home electrifying. Yikes. I'd really like to retire someday and this is not helping. With higher housing values or a different financial position, I would strongly consider this plan.

Whole Ass: $250-400K

• Reasonable But Effective plus:
• Remove wood siding and add continuous exterior insulation and a suitable new siding layer like Hardie Board to suit this historic home. I'd look to approach Passive House performance.
• Replace windows with very high performance ones, again probably looking at Passive House type tilt/turn European windows. 
• Attack any air sealing opportunities with gusto. I'd target 1000 cfm50 or so blower door, about a 75% reduction.

I've learned there are two ways to do anything: right and again. This is doing it right. My dad would be happy.

But my dad also went bankrupt trying to restore another historic home. I don't really want to follow that path, although if I was older and had plenty set aside for retirement I would consider this.

Another reason I'd consider it is if housing values could support it. If this house was 10 miles away in Hudson, a high end suburb where I went to high school that has double or more housing values, that could be on the table. But it wasn't. So we had a decision to make.

Reasonable But Effective Solutions

What I was searching for on this house, and on my client projects, is a "reasonable but effective" solution. The typical "low hanging fruit" aka half @ass solution seldom achieves desired results on complex projects like this one. This is not a new thought process for me, in fact I said that Low Hanging Fruit Is Poisoned all the way back in 2015.

"Reasonable But Effective" solutions cost more than low hanging fruit options most of the time, but they carry 80%+ odds of success and don't ask impossible things of contractors. Two ducted systems plus fixing the top attic was the path for this home, but the cost was more than we could justify at that time. 

I've recommended selling their home to a few clients, it's far from my favorite thing to do, but sometimes it's the logical option, so I always consider it. 

You can also go whole @ass and nearly guarantee good results, but it's often not worth the time, money, and effort. My friend Quint David reminded me today that when it's cheaper to buy solar panels and generate the energy than it is to do the performance project, strongly consider adding the solar panels. Or just switching to renewable electricity suply so the money is being used to put up solar panels or wind turbines somewhere. There's a place for full bore projects, but they're pretty rare in my experience. 

I'll write a proper article about Reasonable But Effective solutions in the future, it's a guiding principle to my work, and I firmly believe it should be to all pros. It's as simple as offering an array of solutions with rough costs and rough odds of success, then letting clients choose. It also shares responsibility so that if results aren't what's expected, it wasn't actually unexpected, and there's a plan for what to do next if desired.

Also, if this house had had a duct system, I would have installed a hybrid/dual fuel system which is a furnace plus a heat pump. This typically reduces gas usage 50-100% (less in older homes in cold climates, more in newer homes in warmer climates). That's often what a reasonable and effective job looks like in my work. 

The New England Challenge & Some Hope

A brief aside before I wrap this article up. The Yellow House as we called it is very similar to many New England homes which are very heavy on boiler systems, much more so than anywhere else in the US. 

There's more hope now on this front, if you have large radiators you could replace the boiler with an air to water heat pump to cover about half the heating load in many homes. Then you could use ducted/ductless systems to cover the cooling load and the rest of the heating load. There are definitely more options today, but boiler heated homes remain some of the most challenging home electrification scenarios. 

I'm hearing prices in the $35-45K range for changing a boiler to an air to water heat pump in New England, which is expensive enough to put other options on the table. It's a surprisingly difficult and detail oriented process, it requires far more thought than a boiler replacement. Ductless mini splits typically run around $5-9K each. Most homes will need 4-8 of them, and you also get AC. This is why mini splits with the boiler left as backup are so common. I dislike how many of the 6 Functions of HVAC you lose with ductless systems, but they are very pragmatic. 

I expect in time this will get more reasonable, but I doubt they'll ever get to the price of replacing a boiler because there's more labor involved (at a minimum there's an outdoor unit and running water/coolant lines to it, plus new radiators may be needed) and the equipment costs more. These systems are pretty common in Europe and the UK, check out Heat Geek's homeowner Facebook group in particular to learn more. 

I should repeat, if the house has duct work, you can always do a hybrid (furnace plus heat pump.) If you are looking at homes and would like to electrify, look for one with a duct system. 

The Decision & Results

Between how hard and expensive this home would be to electrify and our goal to actually get on track for retirement, we made the hard decision to sell the home. We fixed all the stuff we'd been dragging our feet on and put it on the market with our friend Heather Lutz-Neal (highly recommended if you are buying or selling a property, she found our fixer upper then a buyer for it too.)

This was our personal decision on this one home. I'm not saying it will or should be your decision.

It's worked out really well, largely through dumb luck. We sold the house for $200K, bought a fixer upper for $72K and put $30K into it, and put the other $100K into the market. As it turned out the timing was great as I pushed much of the money into the market during the major dip caused by the beginning of the COVID pandemic. Dumb luck. We have since sold the fixer upper (AKA the River House) and nearly doubled our money on it. Again, dumb luck as the housing market got hot. 

After seeing how well the River House did on AirBnb, we bought an 1150 square foot double wide in southern West Virginia with the New River Gorge National Park literally in the backyard. We originally planned to use it in the summer, but liked the area so well that we sold the River House in Ohio and officially moved to West Virginia. WV is one of the cheapest places in the western world to retire, and we were planning to do so, we just moved that date up 20 years or so. 

We've now created a number of themed all electric AirBnbs: the Game House which is board game themed, the Wizard House where you can stay in a small version of a famous wizarding school, Mothmanor which is themed after the West Virginia monster Mothman and is also a whole house escape room, and the Lucky Penny camper. We're gearing up to create a bunch of cool glamping units too which help satisfy my wife's extremely strong artistic drive. If you'd like to see what a kick butt all electric house feels like, come stay in one sometime! 

I'll write about the HVAC and performance projects on the other houses in time as well. I greatly enjoy having all of these laboratories where the only person I have to convince is my ever tolerant wife Rachel. I do chuckle though as I've long given fellow pros a hard time for only writing about their own homes when the real learning comes from selling and executing these jobs for clients. If you'd like to see some of my client case studies check this page out. I do remote consulting if desired, check out the contact us page on this site. 

I'm confident that the technical challenges of creating high temperature water with heat pumps will be solved so that the electrification of the Yellow House can be a drop in replacement of the boiler. It's already possible with carbon dioxide refrigerant (although you would need 4 of them because they're small, and you couldn't do cooling.) Or you can use two different refrigerants to do the lift which is called a "cascade" system. A few of these exist but they are very low volume at the moment. It was obvious that those solutions were 5-15 years out as we made the decision to sell in 2019. 

Many of these hard to electrify homes will get far easier to electrify in the next 5-10 years. 

Meanwhile my wife, our daughter, and myself all miss the "Yellow House" as we called it. Our newborn son will never miss it though. =)

It went to a really lovely Connecticut couple who had recently retired and were following their grandkids to the area. They said they'd done the same downsize routine at our age as well. It was a really warm transaction and we stay in touch. I know that he and his wife will continue to steward the home for future generations just as we did for 9 years, including our daughter being born there. After all the Yellow House was 30 years old when Abraham Lincoln delivered the Emancipation Proclamation, what else will it see in the next 100-200 years of its existence?

That said, selling it opened up a bunch of new possibilities for us, and did indeed get us on track for retirement, so it turned out to be a very good choice in the end! Hopefully this discussion of various options helped you as well. 

Looking for Help?

If you are reading this and trying to figure out how to electrify your home, I highly recommend reading my book The Home Comfort Book, much of which is available for free download on this site, and also taking the free #electrifyeverything course. Then you may want to buy an hour (which is usually 1.5-2 hours) here. Good luck!

PS I emailed Eric Werling, head of the Department of Energy's Building America program on 9/8/19 to ask for an air to water heat pump with 60K output at 180F water temp when it's 5F outdoors. He said that's a very challenging specification and nothing he knew at the time came close.  Lack of a high temp boiler replacement is the only significant technical hole in home electrification. Like I said, I expect it to be solved in the next 5-10 years, but it's 5 years after the decision to sell the Yellow House. =)

Nerd Level 5/10: TLDR Warning: Data Heavy To Make a Point: Reheat Dehumidification Is a Great Tool At a Reasonable Operating Cost When Used Correctly

Last time I showed how reheat dehumidification works to keep your house both healthy and comfortable. If you haven't read that, I'd start there first so this article makes sense. Reheat is a great way to keep your house dry and healthy while only requiring one piece of equipment (a higher end heat pump system.)

Once I explain what reheat is, the next question is always something like this: "you mean I'm running both my air conditioner and backup resistance heat that's known for being expensive, doesn't that make reheat dehumidification really expensive to run?"

I'll let my client Brad Mueller answer with a LinkedIn comment about my last article showing how reheat works:

I let Brad steal my thunder: done right* reheat dehumidification costs about the same as a traditional $250 dehumidifier you see at big boxes like this one. 

Standalone dehumidifiers typically use 500-1500 kwh/year in my experience, that's the number to keep in mind when looking at reheat dehumidification usage. 

In this article I'm going overkill on projects and data to show that this is more than anecdotal: this is effectively a small study and carries a pretty high level of confidence.

My goal is to show that reheat dehumidification is a useful tool that doesn't carry an unreasonably high energy penalty when used correctly. In fact typically it carries little to no penalty at all. 

We'll look at a number of projects from different angles:

• A deeper look at Brad's house
• Clients with high energy usage for reheat, why, and how we got it fixed
• Typical clients of mine to show what to expect
• Friends' houses in humid North Carolina and Louisiana to counter arguments about how this varies a lot by where the house is located. (It varies some, but not THAT much.)
• A comparison of our four houses in the New River Gorge National Park area in West Virginia. Three are AirBnbs, the fourth is our house. 1 has reheat, the other 3 don't.  

My Goal: Only Require One Small Dehumidifier

My goal is to reduce the dehumidification needs of the house enough with reheat that one of the above inexpensive dehumidifiers is enough to make up the slack when the reheat can't do it's job (there are times when dehumidification is needed in heating mode, which no residential system is presently capable of.)

These low cost dehumidifiers last longer because they don't have to work as hard. I'll show this with one of our own AirBnbs at the end of this article. But first let's look at the usage from Brad's house. 

Like we discussed last time, I like whole home dehumidifiers, but they consistently have shorter lives than new home HVAC systems, so you'll probably need to buy two in the lifespan of your new system. If I can get that work done without one, that's my preference. I do like them and use them when clients recently bought a system and don't want to replace it. 

Detailed Look At Brad's Energy Usage

​One of the many reasons I like the Carrier Infinity thermostat and system is that it tracks energy use. Until 2016, energy monitors were quite expensive, about $1000 for circuit by circuit monitoring. Plus install. I only had one project willing to spend the money to get one. 

In 2016 the Sense energy monitor came out to track whole home usage and some of the individual appliances that were obvious on/off items like dehumidifiers, microwaves, vacuums, etc. It did not pick up variable speed equipment like the heat pumps I use. At $300 vs $1000 I used a number of them, but I couldn't learn much of what I wanted to learn and they didn't improve their detection substantially over time. 

In 2019 or so the Emporia Vue Gen 1 came out which was very nicely priced around $150, however it was missing voltage monitoring which is key for accuracy. The Gen 2 Emporia Vue came out in 2020 and added voltage monitoring, and Gen 3 just hit the market late last year. I recommend using them in any electrification project so you can figure out a) how equipment is running and b) figure out high usage when it's an issue.

But early on, the only way to watch usage of my systems was with the Carrier Infinity, Bryant Evolution, or ICP Ion thermostats, which is what we're going to look at.

What's particularly fantastic is that these products break out usage by task: cooling, heating, fan, backup heat, and reheat dehumidification. No other system I know of does this, and whole home monitors can't break things out like this either. Take a look at this chart because I'll be showing many like it. 

Brad's system went in in December of 2017, here's a screenshot from 5/1/20, note the electric reheat line for 2019. 

627 kilowatt hours for dehumidification is not uncommon, at least in the Cleveland area. I usually see 50-200 kwh/month or so. Your mileage may vary by climate and month. 

I believe he has a separate dehumidifier, but I'm not sure and I have no way to know how much energy it's using. Like I said energy monitors got inexpensive right as I quit practicing in person. I'll show data from our WV homes at the end of this essay.

Power was about $.14/kwh at this time, so reheat cost Brad about $90 this year. 

Here's a fresh screenshot as I write this on 11/24/24. Note that reheat usage has dropped to zero. This is possible in homes that have a vapor barrier below them so that little moisture comes up through the earth. Combine this with a system that does a good job on dehumidification and zero reheat usage is possible. 

By the way, you can get a good idea if your home has a vapor barrier under the basement or crawlspace floor by testing with an inexpensive (~$40-50) pinless moisture meter. Measure on a day after rain so it's likely to be wet. If you put it on the floor (set to masonry mode) and it reads green, you probably have a vapor barrier. If it reads red you probably don't have a vapor barrier. 

These readings are at my client Kevan's house, you can read his full case study here. The walls of Kevan's house were incredibly damp, they were the main moisture source in the basement. We coated them with closed cell spray foam which improved it greatly. 

Usually most homes post 1960 or so have a vapor barrier under the slab, but not always. Post 1980 nearly 100% do. 

Back to Brad's house.

Brad's shell work is now complete, basically the entire house has closed cell spray foam on it now. Here's one wall we did from the outside in December 2017. The house also got an addition which you can see in the rear. It was colder than I would have liked when we did this work, thankfully it was successful, we purposely overheated the interior to make the "substrate" we sprayed to warm enough to cure the foam. 

A Few Notes on Projects

We'll get back to reheat shortly, but I wanted to show that these are real projects, I generally have 1000+ photos from each of my house whispering projects, of which I did nearly 50 from 2014-2019. For more case studies see energysmartohio.com, which is an archive site now that we've moved to West Virginia.

One other thing, you'll probably notice that most of these screenshots are 4 years old or more. That's because:

• We moved to West Virginia and I closed my Energy Smart Home Performance in person practice. I stick to remote consulting now.
• I was hot and heavy learning how these systems worked in 2017-2018, at some point you learn most of what you're going to learn and stop pushing as hard to learn.
• Carrier also updated the app and I don't like it as well. =P

OK, let's look at actual projects. If you're like me and you see one star reviews, you go read them to see if the reviewer has a legitimate complaint or if they are just a complainer. So let's start with the 4 projects of mine that were, um, learning experiences. 

The Worst Client Systems

I've had four clients that used more electricity for reheat than we initially expected. There were two main causes: not having wifi so I couldn't catch high usage before it was an issue, and new construction homes where the concrete needed to be dried out. I prefer to be upfront with less than perfect projects, so let's look at them. 

My Cousin Ryan

My cousin Ryan is one of my whole home electrifications, he has a nice 1600 sf ranch style home in the Akron OH area. Note his incredibly painful electric reheat usage of 4215 kwh in 2018, by far the worst of any of my clients. Cost is at $.13/kwh or $463 for the year which was right at the time. By far the highest usage of any client.

There were two main culprits here: no wifi so I couldn't monitor his system, and operating the house the wrong way for reheat. 

Ryan and his wife weren't home much in this period, so they just used their phones when home for internet. In this period I was watching client homes like a hawk and was bummed I couldn't see what was going on, I even bought him a new wifi router when his failed. 

Then one day I got a call that his usage for electric reheat was insane. So I asked him to send me screenshots. 

I was flummoxed for a bit, but then asked him how he was running his AC. He said he ran the AC during the day but opened the windows at night. 

AHA! In most of the Midwest in spring/summer/fall, it's humid at night. So if you open the windows and you've painstakingly dehumidified your house all day, you let that outdoor humidity back inside where it soaks into the walls, ceilings, floors, furniture, and so forth. 

Then the next morning he would close the house back up and turn the AC on. The AC and reheat dehumidification would dutifully dry the house out again but use a ton of juice doing so.

With reheat dehumidification engaged, his 2 ton Bryant Evolution 288 heat pump worked like crazy to dry the house out all day, only to have him open the windows again at night and let all that hard fought dehumidification work go to waste.

We agreed to turn off reheat dehumidification on his house and I helped him do it on the thermostat. That stopped the usage, but note that it was a windows open/closed strategy mixed with no wifi for me to watch the equipment that lead to this issue. It wasn't the equipment's fault. 

​New Construction Project 1​

In 2018 Ed Kisiel of EKA Build built the tightest home I've ever tested, a 2200 sf ranch with a 535 cfm50 blower door west of Cleveland.  It is very nearly Passive House tight yet only used traditional methods and products. If you live in Cleveland and want to build a house, call Ed. I'm seldom impressed by builders, I very much am with Ed, his attention to detail is amazing.

We offered the clients multiple HVAC choices, they chose a heat pump system, a 4 ton Bryant Evolution 288. It was bigger than I would normally do because it was the first time I'd used this system I was a chicken. 

A month or two after completion, but before they'd moved in, I got a text that the electric bill was far higher than expected, about $200 for an unoccupied home that was supposed to be efficient. I asked for a screenshot or photo of usage and got an earlier version of this:

This was a case of where assuming had its usual you and me effect. 

New homes are still quite wet, we build with basements in most of the Midwest, so the mortar in the basement walls and concrete floor are wet for as much as a year post construction. 

I assumed that the clients would a) move in quickly and b) set the AC in the unoccupied house to 75F or so. 

I was wrong on both counts. They set the AC to 70F and waited about 4 months to move in. I had set the dehumidification target to 46% relative humidity (as low as the system will go), and a lot of energy use ensued. 

That was the cost of drying the house out. From experience a regular dehumidifier would have used a similar amount of energy, but it would have spread it out over several months and made it less noticeable. Asking for a dry house with a powerful dehumidification system (the heat pump with reheat) meant we got a dry house quickly but somewhat expensively.

We changed the humidity set point to 52%, which is where I start client homes now, and this is what happened:

With a more reasonable humidity set point and a tight new home that doesn't let much moisture in (once it dried out of course...), reheat dehumidification doesn't run much. 

No Wifi Take 2

The third client with higher than expected reheat dehumidification usage was similar to my cousin in that his thermostat wasn't connected to the internet so I couldn't check on it. In the end his usage wasn't that unusual.

He's a private guy and an IT professional who's concerned about data breaches (and a real pleasure to work with), so he didn't want any internet connected devices and he uses Proton Mail for email. All good, I roll with the punches. 

But, you guessed it, I got a text that the usage was higher than he'd like as he bought solar panels and wanted it to cover all his usage. 

300 kwh in a month is not low, but to be frank it's not that high either. It's about $40/month at the time. The dehumidifier in my basement a few houses ago was using 200-400 kwh or $35-55/month in electricity. So this isn't really that bad if your house needs dehumidification. 

​We adjusted his relative humidity set point higher, I've found 52-54% works well. I asked for an updated screenshot, he just texted me this:

771 kwh is a little on the higher end, but this house was built in the 1960s, so it likely has no plastic under the basement floor like most older homes and therefore needs a bit more dehumidification. 

I'd like to note the electric heat (backup resistance) line too. This is a 3 ton model of midrange Carrier Infinity VNA8 which has just ok cold temperature performance. This is in a ~2200 sf 1960s house with a 600 sf 2019 addition.

Despite that it's only using 400-500 kwh/year of resistance. If this was a GreenSpeed VNA4 it would be near zero, but at $50-80/year of usage, who cares? I've gotten much more comfortable using this unit in Cleveland and other fairly cold climates. It does not qualify for the federal IRA incentive though. 

We got the house quite tight, a 1460 cfm50 blower door at the end, we started at 4100 cfm50 and 1600 square feet to begin. Pretty amazing to add 30% to square footage but reduce leakage by 64%! Good attention to detail helps a lot here, R-Tek insulation did a nice job. A decent shell makes heat pumps work well in cold climates like Cleveland. 

One more new construction one

I'm writing this while visiting my inlaws for Thanksgiving, and had dinner with my spray foam contractor Gary Smith of Affordable Foam who just built an 1800 sf barndominium with a remarkable 340 cfm50 blower door, the tightest I've had direct experience with. He bought my old blower door to test it with. 

He had a similar experience to the other new construction example, and used a fair amount of energy drying out the home which is built on a slab. 

The reheat usage is high at nearly 2000 kwh or $258. That's the cost of drying out the concrete and other building materials. 

That said note that the total cost to heat and cool his home is $942 so far this year and unlikely to break $1100 or $92/month.

Paul's house drove me bonkers, the dehumidifier in the basement would keep the basement super dry, but the rest of the house was consistently breaking 60% relative humidity. You can see when I made adjustments at noon 9/19.

By adding a return in the basement so the dry air down there could get mixed with the rest of the house and turning on reheat dehumidification, we finally got control of Paul's humidity. 

I started using Indoor Air Quality monitors in 2014 with the AirAdvice, then dug into them deep in 2016 when the first generation of consumer grade sensors came out. I quickly figured out that I did not have control over humidity on our projects which frankly scared me. 

Here's what reheat usage from those first two days looked like. On humid days the about same amount of energy was used for reheat as it was for cooling. Tuesday is the day I turned it on at noon. 

Here's what the energy usage looked like for 2017.

Paul's house has used around 700-900 kwh/year for reheat since then. His dehumidifier is also running, but this is before I could buy a reasonably priced energy monitor. An Emporia smart plug is only about $10 and can measure dehumidifier energy usage, I'll show data from our 4 WV homes at the end of this essay. 

Paul's house is where I cut my teeth on reheat. I'm thankful because I was really worried I might make him and his lovely wife sick if I didn't keep the house dry enough to prevent mold from returning. 

Cindy's Condo

OK, let's look at a modern home. I define modern as anything built since 1980, construction methods have changed little in about 45 years. 

Cindy's condo is near Youngstown Ohio and is 1250 square feet. It had a 57,000 btu furnace that we downsized to a 2 ton/24,000 btu Bryant Evolution 280 heat pump (that turned out to still be oversized.) I also did a little air sealing and knocked the leakage down from 1150 cfm50 to 830 cfm50. 

Her house is on a slab (rare in my area) and almost certainly has a vapor barrier under it aka plastic or visqueen. So it doesn't have the humidity problems that Paul's 1900 built home with a damp basement has. 

​North Carolina System

I want to head off any complaints about only looking at reheat dehumidification in systems in Cleveland Ohio. We'll look at two.

The first is from my friend Reedie Ward's house. Reedie is a former technician and now works in sales. He has a 3 ton Carrier Greenspeed. His house is about 2000 square feet and is moderately tight (I forget the exact blower door number.)

Note that the house is using far more electricity for cooling vs heating, it's a fairly mild climate, although it's hot and humid in summertime. 

Note how it's using near zero reheat because the system is sized well, the variable speed heat pump is very good at dehumidification, and it's hot enough that the air conditioner can tackle the dehumidification work. 

Louisiana System

My friend Mark Hanneman is a long time technician and business owner who lives north of New Orleans and recently built a new 2700 sf house with a 3 ton Carrier GreenSpeed. It's pretty tight but not crazy tight. 

I think you could argue that Louisiana is the most humid climate in the US alongside Miami,  their dew points are above 70F for most of the year. Around 70F dew point it feels like you can cut the air with a knife.

Like Reedie, Mark's heat pump does far more cooling than it does heating. It's so humid that the reheat needs to do some work, and you'll see that his usage is in the ballpark of the other projects I've shown, 1200-1500 kwh/year.

Louisiana has some of the cheapest power in the US at about $.10/kwh. US average is about $.15, a few places like CA and MA run over $.40/kwh. 

To repeat what I said at the beginning, done right reheat dehumidification costs about what a dehumidifier does.

OK, onto the last set of data: a comparison between our houses in southern West Virginia. 

Comparing Houses With and Without Reheat in West Virginia

I've accidentally created a dehumidification experiment in the New River Gorge National Park area. 

We bought a house here in 2021 intending to use it seasonally and AirBnb it the rest of the year. We liked the area so well we sold our house in Ohio, and we've been creating themed AirBnbs: a board game themed one, a Wizard themed one, and a Mothman themed one. 

Naturally I've electrified all of them: they're all small and don't justify a furnace, plus a heat pump can provide far better comfort. None have a gas meter anymore.

The house with reheat actually used quite a bit less electricity than the houses I use standalone dehumidifiers for. I don't think you can come to a firm conclusion from this one data point, but it's interesting. All of them have vapor barriers in the crawlspace or basement. 

We live in the mountains, so the summer temperatures are usually cooler than Cleveland where I'm from, but the humidity is pretty high still, we usually spend most of the summer above 70F dew point which is pretty sticky. 

This is a very challenging climate for dehumidification because it's often not warm enough to run the AC hard, but there's still a ton of dehumidification work to do. Hotter climates are often easier in this regard. So dehumidifiers get worked pretty hard. 

Another key note is that it was an exceptionally dry summer, we were in severe drought this year, so dehumidification load was lower than normal. 

Let's take a look at each house. 

Our House

I'd been wanting to try a Bosch heat pump, it's priced lower than many higher end heat pumps. I didn't want to recommend it to clients until I had personal experience, so I put one in our house.

Sadly, I have not been impressed. The first year I thought that the condensate drain had come disconnected because I never saw it dripping. I asked a bunch of friends for help setting it up, it was indeed connected but it was doing such a bad job at dehumidification that it was not removing enough moisture for the drain to drip.

It has a switch to run a colder coil, but even with the switch flipped to run the coil at 38F and dehumidify better, my dehumidifier uses more power than the AC some months. The house is 1150 square feet and is pretty tight, about 1000 cfm50 with an encapsulated crawlspace. 

​Without running the dehumidifier the relative humidity in the house quickly climbs above 70% RH which is both uncomfortable and unhealthy. 

Here's monthly usage for the AC and dehumidifier. The AC is measured with my Emporia Vue energy monitor, the dehu with an Emporia smart outlet. 

Note how the heat pump (air conditioner) is using about 250 kwh/month in summer and the dehu is using 150-200 kwh/month. Last year the dehu used more power than the AC most months. 

​Here's total annual usage to 11/28/24. Note the dehu near the bottom at 1160 kwh, more than my water heater this year and the second largest user in my house. Dehumidification season is over for the year, it just turned cold, so this and the other readings should remain valid for the year. 

​Note 1160 kwh is as much energy as Mark Hanneman's reheat used in Louisiana. 

Mothmanor

​OK, let's do the house with reheat next. Mothmanor has a 2 ton 5 stage Carrier Infinity VNA8 (in Heil brand, but the same product). 

It's a small 620 square foot ranch with a full basement. It was built about 1950, so no vapor barrier in the basement, although I added one in the renovation. I need to do a final blower door test but I'd guess in the 1200 cfm50 range. Not super tight, but controllable with HVAC. It's super comfy. 

Here's a 11/28/24 screenshot of year to date usage. 

Reheat was a whopping 271 kwh this year. 

​Here's the annual usage according to the Emporia Vue energy monitor at Mothmanor. Note that the Carrier Infinity thermostat seems to be overestimating usage by about 10%. 

I also have a dehumidifier at Mothmanor for a belts and suspenders approach to dehumidification. The house was really rough when we got it, and animal hoarding situation, so I want to keep it very dry to prevent any potential odors from returning. 

271 kwh of reheat plus 326 kwh of dehumidifier usage is a whopping 597 kwh, right in range with what we've seen on middle of the road projects elsewhere. 

That's about half the 1160 kwh our house used.

Mothmanor also has twin fresh air intakes which add a fair amount of humidity to the house, ironically I don't have a fresh air intake on our house yet. 
​
Just for giggles, here's the monthly dehumidifier consumption. ​I'm probably missing a few kwh from March and April to those with a sharp eye.

The Game House

The Game House is actually an apartment over a 4 car garage, it's 800 square feet of living space above an 800 square foot garage. It has a 1.5 ton Daikin Fit (thanks to Roman Baugh for helping me get it set up right.) It was built in 1979 and is pretty well insulated with a 1300 cfm50 blower door. It has a vapor barrier under the garage floor. 

I just have a dehumidifier downstairs. Here's the annual usage to date for the house:

The dehumidifier has used 1022 kwh so far this year, I doubt it will use much more as the weather just turned cold. 

​This house serves as our laundry room for our AirBnbs, hence the high water heater usage. I put a heat pump water heater in in June. The laundry room is a bit of a confounding factor because the door to the basement gets left open a lot in summer, letting humidity in. 
​
​Here's monthly usage for the dehu and heat pump:

The Wizard House

The Wizard House is directly next door to the Game House (it was the mom's house, the Game House was built by her son). It also has a 1.5 ton Daikin Fit heat pump. It's a 672 square foot ranch built in 1950. It's badly insulated, the walls are empty and the attic only has 2" of insulation in it. I left it that way on purpose as an experiment (and we had run out of money lol.)

The basement was horrifically wet, I joked it was like A River Runs Through It only without Brad Pitt. I encapsulated the basement/crawlspace and spray foamed the walls down there. I never blower door tested it though. Shoemakers' kids and all. 

I'm concerned about mold returning in the basement, so I set the dehumidifier in the basement to 45% RH, normally I run a 50% set point. It runs quite a bit, and is a confounding factor to be aware of. 

Here's annual usage to date at the Wizard House. 

The dehumidifier here used 1269 kwh so far this year. 

The water heater is also interesting to me, this house runs nearly 100% occupancy March-October with groups of 4-6 and an electric resistance water heater only used 1571 kwh, just a little more than the dehu. 

Here's monthly usage for the dehu and heat pump for consistency's sake. 

West Virginia Conclusion: Reheat Ain't Bad

To review, here's the usage in kwh and cost at $.18/kwh so far this year of dehumidification in our 4 WV houses:

597,   $107  Mothmanor (271 reheat, 326 dehumidifier)
1022, $184 Game House
1160, $209 Our House
1269, $228 Wizard House

This is not a perfect study, but the houses are comparable in size, and the Wizard House/Mothmanor are nearly identical in build year, construction, and size. 

I think it does help illustrate how reheat dehumidification is not a giant energy cost. It's comparable to running a regular dehumidifier. 

Conclusion: Reheat Is A Useful Tool 

If you made it this far, thank you! And maybe grab an adult beverage, you've earned one!

You've seen a ton of examples from clients with higher than expected usage, clients with expected usage, friends' houses in other states, and our 4 houses in WV. 

In general I see energy usage from reheat dehumidification in the 600-1200 kwh/year range which works out to $60-240/year at $.10-.20/kwh that most of the US sees.

Like I said at the beginning, standalone dehumidifiers in my experience use between 500-1500 kwh/year. 

So does electric reheat dehumidification. If you use it right, which includes:

• Stick to set points of 50% relative humidity (RH) or higher.
• Use the right equipment - results are nowhere near this good with equipment that can't dehumidify well (I'm planning an article on that, but it'll ruffle feathers, so I may not.)
• Don't open windows and use reheat (it's a bad idea in general in humid climates).
• In new construction be aware that you'll need to dry the house out and it's not free.
• Pay attention to electric usage, a $15 smart plug can tell you about a dehumidifier, a whole house energy monitor is a good idea if you are using reheat with anything other than Carrier/Bryant equipment. 

If you live in a humid climate along with 80% of Americans, perhaps you'll consider a heat pump system with reheat dehumidification capability. 

I'll be releasing my Common Sense HVAC Guide soon which will add more detail to what the actual install looks like, keep an eye out for it!

* I've definitely seen reheat done in an inefficient matter. One small study in North Carolina found that using reheat dehumidification was projected to use $768/year more electricity vs a whole home dehumidifier. That study used a Bosch heat pump which is not that great at dehumidification, so you have to add a lot of heat for it to dehumidify well.

Jim Bergmann of MeasureQuick and I both bought a reheat capable thermostat (American Standard 824) paired with a Bosch heat pump. We tried reheat on his shop and my house respectively, and quickly concluded that it was good at burning a lot of electricity. The NC setup was better, but judging by the wildly higher energy cost, a product better at dehumidification should be chosen. 

I've also heard about usage on a restaurant in the Miami area using their single stage AC for reheat. It worked, but the bills were eye watering.

​I've come to firmly believe that you need a fully communicating system that can run the indoor coil very cold if you want to keep energy use down while using reheat dehumidification. It's possible to do it other ways, but hard to get set up correctly.​

Nerd Level 5/10 - I'll go slow but this is a bit technical. It's one of the most important concepts I teach though, it's often the key to a healthy home. Part 2 is about what it costs, read that once you've read this post. Link at the bottom.

A Dry Home Is A Healthy and Comfortable Home 

Reheat dehumidification is a fairly obscure topic, it's common in commercial HVAC but not residential. In all my years of house whispering, humidity control has been by far the most challenging part, especially in older homes that don't have a plastic vapor barrier under the basement floor, or homes with vented crawlspaces. 

Keeping a house dry during humid seasons is critical to indoor comfort, reducing thermostat wars between spouses,  reducing the growth of nasty stuff like mold, mildew, and rot, and keeping the house and indoor air quality healthy. I target 45-55% relative humidity (RH) which is 45-55F dew point in cooling season. 

In humid climates where the grass stays green without having to water it* there are typically several months per year where it's humid outside, but not warm enough to turn on the air conditioner or have it run very long. Sadly, the days you'd like to open the windows when it's 70-75F/20-24C out are often these times. I don't make the rules, physics does, I don't like this either!

If you have noticed your house feeling sticky in spring or fall, or noticing where the dog peed last year, humidity is probably getting too high in your home. If you break 60% RH in your home, the odds are high something bad is growing somewhere in your home, often inside walls, crawlspaces, or attics where you can't see it (but you still breathe it.)

As air conditioners have gotten more and more efficient, they are actually getting significantly worse at dehumidification. 

Myself and fellow building science nerds have noticed a significant bump in mold and humidity complaints in the last five years, in fact I did a presentation in 2018 called The Coming Mold Explosion. 

So what's the solution? HVAC systems that have excellent dehumidification capabilities, in particular those with "reheat dehumidification". I view it as real world magic like air conditioning and flight: even though I understand how it works, it still seems like magic!

Let's take a look at what reheat dehumidification looks like. First, we need to look inside your air conditioner. 

​The First Nerdy Part: The Indoor Coil

This is a picture of the air handler unit (AHU) now installed in my house, AHU is the name for the indoor part of a heat pump (a heat pump is an AC that can heat and cool where an AC can only cool.) If you have a furnace and AC, the coil sits on top of your furnace and the furnace unit has the fan in it. 

On the bottom is the fan, the air handler itself. Above that is the indoor coil. This unit is set up for downflow operation, where the air blows from the top to the bottom and into duct work in the crawlspace. If you have a basement your system is almost certainly setup as an upflow unit, and in an attic or crawlspace as a horizontal flow unit. 

​In this case it's an "A coil" because it's shaped like a letter A, some are flat (aka a slab coil), some are shaped like a letter N (you guessed it, an N coil.) 

When the indoor coil gets cold, it removes heat from the air inside your home so it can pump it outside. 

​When the coil gets cold and it's humid inside, the coil will get wet with condensation. I don't have a good picture of that, but here's condensation on the bottom of another air handler that is in a very humid crawlspace (since fixed.)

Hitting Set Point Too Fast to Dehumidify

When your air conditioner is running, it's removing both heat and humidity from the air inside your house. 

An AC needs to run for a while, 5-15 minutes, before the coil gets cold enough to dehumidify. Until then it is just removing heat from the house, which you think of as cooling.

This is problematic on mild days because the air conditioner will remove heat too quickly so the thermostat is "satisfied" and the AC shuts off before the coil gets cold enough to start dehumidifying. This leaves your house cold and wet which is a recipe for high humidity, mold, and discomfort. 

A Partial Solution: Variable Speed AC

If an air conditioner is too big to run long enough to dehumidify, one option is to make it smaller. You can choose a smaller size in a typical single stage on/off model, but the real key is to buy a variable speed AC or heat pump that can turn down to a very low output.

The best variable speed ACs or heat pumps can turn down to about 25% of their full capacity. A 2 ton/24,000 btu AC or heat pump can turn down to 6,000 btus. For reference the smallest window air conditioners are 5,000 btus and this is for an entire house. As small as this is, it still typically leaves several months where it still shuts off because it's not warm enough to run the AC for long before the thermostat satisfies.

The other key is that variable speed units need to turn down low while also running a cold coil so that condensation forms and they dehumidify. Only a few systems do this well. That's for another article. 

The problem is that on mild days in the 70-80F range, even very low outputs will often cool the house before dehumidifying it enough. 

The Actual Solution: Cool and Dry the Air, Then Reheat It

Here's why I had to tell you about the coil inside your air conditioner. It's the first step in reheat dehumidification. It removes heat and humidity from air going through it, making the air cold and dry. 

But we've already established that this is bad, it overcools a house without dehumidifying it, and bad stuff can start happening. 

To fix this, we need to "reheat" that cold dry air so that it is room temperature dry air. 

We can do this two ways, by running it through a second coil with the now warm refrigerant in it often called "hot gas reheat", or by using electric resistance that looks a lot like the coils inside a toaster but larger that's called "electric reheat". 

In commercial systems, the second coil/hot gas is quite common, but in residential systems this adds a lot of cost, complexity, and risk of early equipment failure. Lennox has a product called Humiditrol that does this, but the two times I mentioned it to contractors they practically ran away screaming afraid of the potential failure risk. 

You can set up a standard heat pump system for reheat by running a Honeywell Prestige thermostat in commercial mode, but note that it will likely use a painfully high amount of electricity because the heat strips will be running for 15 minutes or so before the coil gets cold enough to dehumidify. And you'll want to be sure you have the airflow settings right so the coil can get cold. It takes a good technician with holistic understanding of how homes work and how to set up the equipment to get this right. I'd love to say that's easy to find, but it seems to be under 1% of HVAC techs in my experience. 

My equipment preference, shockingly, is variable speed equipment with 2 or 3 stages of backup heat so that they can run low and slow while dehumidifying which is both more efficient and more effective. More in a minute.

Let's look at a few other factors about reheat and alternative methods to see why I've settled on using it as the first line of defense in my projects. ​

Superior Longevity

I've been called crazy for my near obsession with reheat dehumidification, but there's a really important reason why: it basically never breaks. 

I've done energy audits on homes with ancient 40-50 year old heat pumps and while the heat pump may not work, the resistance backup strips worked every time. As long as the fan turns on to flow air over them and prevent them from melting themselves, they almost never break. 

Another Solution: Whole Home Ventilating Dehumidifiers

In the typical home furnace and air conditioner system, the furnace comes before the AC coil, so you can't reheat the air**, you can only feed very hot air into the AC coil which is very likely to break the system.

Therefore home HVAC systems with a furnace can't do reheat dehumidification whether it's paired with a one way AC or a two way AC heat pump (aka hybrid or dual fuel system). 

What's the Best Way to Do Reheat Dehumidification?

Remember how I talked about the best partial solution to good dehumidification is a variable speed AC or heat pump that can run a cold coil at low 25% capacity to provide the best comfort without reheat?

The best reheat dehumidification is done with that nice system running a cold coil at low capacity matched with as small a resistance backup heat strip as possible. 

This means the system will run for a while at low capacity, sucking as much humidity out of the air as possible. 

What's the Worst Way to Do Reheat Dehumidification?

While you can do reheat with a basic single stage AC or heat pump with electric resistance backup heat strips, it tends to burn far more energy. 

Remember how I said that an AC needs to run for 5-15 minutes to get the coil cold enough to dehumidify well? If you don't want to overcool the home, you need to run the resistance backup the whole time the AC is on. 

The resistance backup is running while the system is not dehumidifying, so you are wasting energy. Plus the AC is very oversized when it's 70-80F outdoors, so it will cool the house faster than you want, using more energy still. 

Ideally you also want to get the AC coil cold fast and run as little resistance backup as possible. More on that in a second. 

What's the Worst System for Reheat Dehumidification?

Many (frankly almost all) AC and heat pump systems are really bad at dehumidification. They focus on cooling over dehumidification. I'll write about this in depth another article, but it's called the Sensible Heat Ratio. An AC can do 65% dehumidification and 35% cooling which is a 0.35 Sensible Heat Ratio (SHR), or it can do 1% dehumidification and 99% cooling, a 0.99 SHR. 

The 0.99 SHR system does almost no dehumidification, even when it's running correctly. 

Most ACs used to be in the 0.7-0.8 SHR range, meaning they did 20-30% dehumidification which is about right to keep a house dry if the AC is sized as small as possible to the house. 

The trouble is that efficiency standards are driving basic single stage minimum efficiency systems into the 0.85-0.95 SHR range. Even if they are running perfectly these systems don't dehumidify well. 

Sadly, efficiency standards have made it where if you want good dehumidification you either have to buy a separate dehumidifier or a "communicating" HVAC system. 

Communicating Systems or Bust

In a communicating system the air handler (indoor unit), the outdoor unit, and the thermostat are constantly talking to each other and making small adjustments in how the system is running to deliver efficiency, comfort, and dehumidification. 

A "communicating" HVAC system is fully variable speed. It can vary the speed of the air handler fan and the speed of the compressor that actually cools (or heats) the house. 

Most importantly, communicating systems can run the indoor coil cold for the best dehumidification and at 25% capacity so it runs a long time and also maximizes dehumidification.  

The challenge is that only two systems are both communicating and do reheat dehumidification: Carrier Infinity and Trane XV heat pump only systems. Each one has multiple brands that are the same products with different badges. 

Carrier Infinity Heat Pumps

While I have two close HVAC contractor friends that swear by Trane XV heat pump systems with reheat, Tim Portman and Stephen Rardon, I have only used Carrier Infinity VNA8 and Carrier Infinity GreenSpeed VNA4 heat pumps. I absolutely love them and finally bought one personally last year. 

Not only do the regular dehumidification and reheat dehumidification functions work very well, but Carrier has the only 3 stage resistance backup heat strips. There is a 3/6/9 kw model (3,000, 6,000, or 9,000 watts) and a 5/10/15 kw model (the glowing photo earlier is the 5/10/15 model running at 15 kw.)

The 3/6/9 kw model of heat strips is an amazing match with a two ton heat pump because it will run at 3 kw and the system at 25% capacity. 25% capacity is 6,000 btus, remember that a small window AC is 5,000 btus. That makes it low and slow, exactly what we want for maximum dehumidification and minimum energy use, something I'll show data on in the next article. 

I should say that Carrier is not a sponsor in any way, in fact I've had zero technical support from them in 10 years of using their products, I've either figured things out myself or learned from other HVAC pros. I can consult on setting your Carrier Infinity system up properly if desired. 

Some Real World Results

This is the relative humidity data from the Haven Indoor Air Quality Monitor in Mothmanor, our AirBnb with a Carrier Infinity VNA8 heat pump system with reheat. It also has a dehumidifier in the basement, I'll show energy use next time. I've noticed that the relative humidity runs a bit lower than what the Haven says, 5-10%. 

It's been a dry year here in the New River Gorge National Park, but the temperatures have stayed higher along with humidity through October. 
​
Here's a chart from Game House AirBnb that has a Daikin Fit heat pump system without reheat, it has a small dehumidifier as well. 

I warned you this post was kinda nerdy, but hopefully it makes sense now how your AC coil needs to be cold to dehumidify well, run as long as possible at as low a capacity as possible, and for the best dehumidification your system needs to be able to reheat the cold dry air that comes off the AC coil. 

To do this, it's best to run as small an AC as possible that is also communicating, which means it can run a cold coil at very low capacity. Only the Carrier Infinity and Trane XV heat pump only systems are capable of this, as well as their other brands like Bryant and American Standard respectively. 

​Done right, reheat dehumidification doesn't use a ton of energy, in fact I'll show how it's the same or less than running a dehumidifier. Like I said at the beginning, I view it like real world magic. 

Here's a comment on this article from cleantech entrepreneur KC Boyce in Atlanta about his Carrier Infinity system and my help setting up/commissioning it:

​Next Up: How Much Does It Cost?

​In the next article we'll talk about operating costs.  I'll show you actual energy use from multiple client systems with reheat dehumidification, friends' houses in warmer climates, and 4 of our own houses in West Virginia - 1 with reheat and 3 without. 

See you next time, and good luck choosing the best HVAC system for your home!


Footnotes
* Green grass climate definition borrowed from Ken "Teddy Bear" Gehring, inventor of the ventilating dehumidifier and a particularly good guy. He's semi retired from Thermastor/Santa Fe, but still active at hvactalk.com
​
** Someone is going to say that you could install a furnace after an AC coil and use it for reheat dehumidification. While technically correct and actually how many commercial rooftop HVAC systems work, it tends to rot out furnace heat exchangers in just a few years because you are running very cold air conditioned air over a heat exchanger that has room temperature humid air inside of it, creating condensation inside the heat exchanger and rotting it out. Those commercial rooftop units are famous for rotting out within 5 years. It's just not a good idea. ​