This is Part 2 of a 3 part series on Indoor Air Quality. See Part 1 and Part 3
Sources of Contaminated Air in Homes
Sources of bad air that enters homes is in our garages (car exhaust, paint, gas & pesticide fumes and dust), the attic (insulation fibers and critter droppings) the space between walls (insulation fibers and construction dust) and the crawl space (dust, dirt, fumes from any chemical stored under there).
How Contaminated Air Enters My Home
Edges of Flooring
Have you ever noticed the dark line that seems to form at the edges of your carpet? In my case, the infrared showed that there was no seal on the other side of the carpet to prevent the air from being pulled in. George explained that the carpet is acting as a filter for the air that is getting sucked into the house, which creates that dark line on the edge of carpets. A simple fix for that is to put backer rod under the edges of the carpet to seal the gap and prevent the air flow.
Garage
Another big source of air infiltration is the garage. Did you know that a car engine puts off carbon monoxide for 30 minutes after the engine is turned off? If your furnace is in the garage like mine, it is pulling that CO right into the house. If you store gas cans, paint and pesticides in the area, the fumes are likely infiltrating your breathing air. As well as the dust that gathers on the floor around the unit. (Have you looked back there lately? It gets nasty quick.) It is a good idea to store all these chemicals outside of the garage if your HVAC unit is there.
In our case, the air handler was not sealed. There were huge openings all around it and it freely pulled dust and contaminated air from the garage. Sealing those gaps was our priority.
George also recommended using silicone caulk to seal the crack in the corner where the garage wall meets the ceiling.
Attic Door
The gap around the pull down steps to the attic allow fibers from the blown insulation and other dust sources, to be pulled into the bedroom, just above where my child sleeps. George told us to use weather stripping to seal the gap. A more sophisticated solution is a bag that goes around the inside of the attic opening to seal off air flow. It unzips for easy access into the attic when needed.
Registers, ventilation fans, electrical outlets/switches and miscellaneous holes in the walls
Using the infrared camera, George and Jerry showed me that there are sources of contamination behind the ventilation fan in the bathroom, around the HVAC output registers and a hole that was in our laundry room wall. There was a capped pipe there for natural gas supply, but the diameter of the hole in the drywall was about 1 inch bigger. To seal these leaks, there are foam insulation products available at home improvement centers, such as Great Stuff.
Jerry and the duct blaster check the air ducts to see how much good air is let out & bad air in.
In many homes, up to 40% of the conditioned air (heated or cooled) is lost through leaks in the duct work. There are many companies that offer to clean your ducts – which is fine, but the bigger concern is that the gaps in the duct work allow the dust to continually be pulled into your home’s breathing air. Remember that the air is coming from the garage, attic, space between the walls and crawl space. The larger issue is to have the duct leaks fixed. Then if you choose, get the ducts cleaned, but sealing the leaks is primary. You and your wallet will be happier when you are not losing all the heated/cooled air to places outside your living space. Using the duct blaster, Jerry and George could calculate the percentage of heated air that was lost through duct leaks, and a leak is also a source of bad air flow.
Part 3 of the Indoor Air Quality Series:
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