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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:  Brad has a 2900 square foot 1960s split level outside Cleveland Ohio that got a significant insulation and air sealing upgrade and a 3 ton Carrier GreenSpeed heat pump as part of a full electrification project. Despite that small system, it only uses resistance backup around 0F. And of course I commissioned the thermostat to turn on reheat dehumidification. 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.  This is a standard portable dehumidifier. If reheat dehumidification does most of the work, these units can live longer than the 2-3 year lives they usually see. 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:
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:
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.  4/2/20 screenshot from Ryan's house - note zero reheat. His outdoor unit had a loose wire which lead to high resistance usage because the heat pump wasn't running. I pushed hard for him to get wifi, it would have helped catch that too! 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:  Yikes! 1278 kwh for electric reheat, and it was all in one month! What happened? 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:  Note 26 kwh of reheat total in 2019. 4/2/20 screenshot so no dehumidification yet in 2020. 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.  10/9/21 photo 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:  11/26/24 photo, note 771 kwh of reheat in 2023 (~$100) and 9 for 2024 at the end of the season. 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.
Outliers Are Done, Let's Look At Some "Regular" Clients Now I've shown my 4 worst examples of reheat dehumidification, let's look at what I saw from other clients. Let's start with Paul, one of my favorite clients. He bought a 1900 era 1300 square foot home in Cleveland and wanted a very comfortable home with low operating costs. You can read his full case study here. This house has a fairly damp basement, so this is one that you would expect high reheat dehumidification usage on. He let the house sit one summer before digging into the renovation, and the basement bloomed with mold. I bought a product to deal with it and sprayed it, then insisted it got a dehumidifier. I've worked with a number of mold sensitive clients so mold in this volume freaks me out and I want to be very sure we keep humidity low to prevent it from coming back. I view moisture damaged homes like cancer patients: they are always in recovery, you can never let your guard down. Paul wasn't a spring chicken (sadly he passed away, I still think of him often), so I wanted to be sure he and his wife had a healthy place to live.  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.  Paul had a housewarming party and I showed up with a sawzall. I cut a hole in the basement return so some dry basement air would get circulated through the house. I hadn't thought about this before this project. I also turned on reheat, this is the project I learned how to do it on, big thanks to Bryan Orr for helping me figure it out.  For my fellow nerds who note that the humidity readings are in relative humidity, here are the temperatures from the Foobot indoor air quality monitors. I had 40 of these deployed in client homes and learned a ton from them, big thanks to Jacques Touillon their CEO. Note that temperatures are pretty similar on all three floors. Just after this Foobot added dew point readings (what I really want to know) but sadly just after that removed the product from the market and moved to commercial construction. 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.  I turned on reheat dehumidification Tuesday 9/19/17. So this is a partial year for reheat usage. Screenshot is 12/31/17. 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.  Screenshot is from 12/31/19. Reheat dehumidification usage will vary by settings, behavior of the occupants like cooking, humidity outdoors, and how much rain comes down and ends up inside, among other factors. 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.  2019 was a full dehumidification season (system installed in March), 151 kwh. This photo is from 6/5/20 when I installed a Haven IAQ monitor. Dehumidification season had barely begun. Sadly I didn't check at the end of the year.  I took this 11/27/24 as I write. 2023 used only 1 kwh for reheat. This year is 171 kwh. At $.15/kwh that's $26. 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.)  This house is in the mountains of North Carolina, you can see that it's heavy on cooling vs heating. 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  This is the living room in Mothmanor, our Mothman themed AirBnb that has HVAC with reheat. 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:
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. |
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