No. 4: Tight Homes Built Without Intentional Ventilation

I don’t know about you, but when I’m in my house, I like having fresh, filtered air delivered to my living space at a rate that’s similar to my respiration. In the old days, this wasn’t a problem; normal air leakage around windows and doors, through sills, and out the chimney always ensured there was plenty of fresh air coming in. But with home construction getting tighter, we have significantly reduced the paths of air leakage. The air that does make it in comes in accidentally, driven by wind, temperature, pressure changes, and perforations in the building envelope. In many cases, this incoming air passes through a garage, crawl space, or attic on its way into the home. Airborne pollutants and dust tag along.

The simple solution is to always design for fresh air. Install a whole-house ventilation system and test its performance. This ventilation and distribution system should ensure that the house brings in and disperses approximately 50 CFM of fresh air for 15 to 20 minutes each hour or so. (See my Spring 2008 column for an explanation on sizing a ventilation system.) Every home built today should include a ventilation system to ensure that the people inside breathe clean, healthy air.