From the ContractingBusiness.com HVAC-Talk.com discussion forum, here are some topics being discussed related to indoor air quality (IAQ). There’s much happening in this too-often ignored service
sector, and much you can learn from your peers on HVAC-Talk.com.
Here are some of the threads you can find related to indoor air quality. Opinions and advice are those of the participants. Comments have been edited for space or clarity.
YOU CAN FIND ADDITIONAL DISCUSSION THREADS AT bit.ly/IAQChats
Is Radon Detection Still Popular? Is it Needed?
A1: If your house is not under a negative pressure and not sealed too tightly, radon won’t come into the house, because it’s a heavier-than-air gas. Radon is one of the densest gases on the periodic table. It’s eight times heavier than air, so it must be brought into the house from a negative pressure condition.
This is why a heat recovery ventilator (HRV) works so well. The more negative pressure sources, such as bathroom and kitchen fans, that are bringing in as much air as they are removing, the less negative pressure your house becomes.
Along with an HRV/ERV, I recommend a 4-in. duct running from the outside to your return air duct, to maintain a neutral pressure when the blower isn’t operating, and a slightly positive pressure when it is. I also recommend ECM blowers using the lowest possible speed, to keep a continuous air exchange in the home and to keep the home at a constant, slight positive pressure. — RoBoTeq
A2: I used to be in the radon business, but I got out. I didn’t believe I was providing any value to my customers. I had a run-in with the EPA at a school where they wrote a letter that was in direct opposition to their published material, that scared the school and parents enough that they removed free-standing HEPA filtration systems in classrooms.
The alleged death statistics are from models. One synopsis of the causes of lung cancer I read managed to account for as many as 117 deaths for every 100 people who died. I guess they counted some people multiple times.
I’m getting ready to install an ERV in my home with the exhaust coming from the bathrooms and the supply going into the living and/or sleeping areas. My intent is to balance it so that I maintain a very slight positive pressure in my home. I will lower carbon dioxide (CO2) levels without as large an energy penalty and prevent soil gases of any kind from entering my home. Anything that does sneak in will be diluted. I personally am convinced that this will do far more for my health and comfort than any traditional radon mitigation system.
EPA’s risk model assumes that you are exposed to the level of radon in question for 18 hours per day for 70 years. — Dirk Roper, ex-Radon services provider