Want to get sick less? Bring in fresh air.

Do you want to avoid getting sick this winter?

Avoid breathing other people's germs by bringing in outdoor air and keeping carbon dioxide levels in the 500-800 ppm range (400-450 is outdoor level.)

At 500 ppm you are rebreathing 0.2% of the air in a building. At 1500 ppm you are rebreathing 3% from other people in the building. I know, gross right?

Readings from my Aranet CO2 monitor that lives in my backpack. The 750 level at the beginning of the chart is from our house. Then I took it outside. The constant level for most of the chart is with both fresh air intakes on the Game House open.

This obviously doesn't eliminate risk of getting sick, but it certainly reduces it.

We're staying at our Game House AirBnb for two nights, and I brought my carbon dioxide monitor in my backpack.

This house has two fresh air intakes, one that is open all the time, the second opens when my Haven Indoor Air Quality Monitor and Controller senses high tVOCs (the sensor is cross sensitive to CO2.) This product is for HVAC professionals only, get 8% off with code NTHW. 

These are twin fresh air intake ducts on the Game House. Each is an insulated 6" duct with a motorized damper set to open and close for different reasons controlled by a Haven Indoor Air Quality Monitor and Controller which is just out of the photo to the right.

​I was pleased to see that with both intakes open CO2 levels stayed below 700 ppm. Note that the intakes are before the filter, so that the outdoor air gets filtered and mixed with indoor air, then heated and cooled as needed. An open window lets hot/cold/humid/polluted air in, this method tackles all those things automatically and inexpensively.

Ironically I'm not sure how much these intakes are flowing, I haven't taken the time to measure. My bet is 20-30 cubic feet per minute (cfm) each. A small bath fan is 50 cfm for reference.

When you buy an HVAC system, I HIGHLY recommend considering a fresh air system of some sort. This is a simple and fairly inexpensive one.

This is one of many considerations in House Whispering. I also want good filtration which can knock many virus/bacteria particles out of the air because they float on spit particles that a good filter can catch.

All this is part of what I call Nearly Perfect HVAC, a guide is coming soon! What questions do you have?

More Info:

Here's an article about the fresh air intake system on this house. 

Here's a deep dive into my thoughts about fresh air ventilation theory and strategies. 

PS Here's the chart from the Haven IAQ Monitor. The dehumidifier is one of the intakes, it's set to be open above 15% relative humidity is which basically 24/7/365. The other intake is set to open when tVOCs get high.  tVOC is total volatile organic compounds or chemical pollutants or in this case CO2 from my family and 2 dogs breathing. I've long advocated for tVOCs before carbon dioxide in measuring IAQ. tVOC sensors pick up far more things, so you know that the air has that many fewer bad things in it.