I live in a 42-year-old house that has never been tested with a blower door. When I’m standing at the sink in January, I can feel cold outdoor air entering the house through the crack between the nearest window and the window stool. My bedroom windows show subtle signs of black mold on the lower sash rails. My house doesn’t have a whole-house ventilation system. None of these facts is unusual; almost all of my neighbors have similar stories to report.
For the last 23 years, I’ve been writing articles that advise builders on how to build comfortable, energy-efficient homes. I know that homes need to be as airtight as possible. I know that thin insulation and leaky windows lead to higher-than-necessary energy bills. But for a variety of reasons, it’s hard for me to implement all the good advice I dish out to readers.
Is my furnace filter dirty?
In my recent review of Allison Bailes’s excellent book, A House Needs to Breathe … Or Does It?, I mentioned Bailes’s advice on determining when it’s time to change the air filter on a residential furnace. The best method, according to Bailes, is to use a manometer to measure the pressure drop across the filter. You should check this pressure drop regularly; once the pressure drop increases to twice the pressure drop measured for a clean filter, it’s time to change the filter.
A few HVAC technicians may employ this technique, but for the vast majority of Americans, the advice isn’t particularly useful. Try as we might, even those of us who aspire to reach nerd nirvana aren’t likely to make it there. Our houses will always be leaky, our insulation R-values will always be inadequate, and our furnace filters will be changed (or…
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