Can a Home Be Too Tight?

Sometime during your crusade to seal those energy robbing cracks and holes in your home, you're bound to start asking yourself, "Isn't air flow important for a healthy home? Can I take this whole thing to the extreme?"

The answer is yes, and probably not.

While it's true that air flow prevents pollutants like dust and mold from reaching unhealthy levels, a leaky home provides no assurance that indoor air pollutants are properly eradicated: during periods of calm weather with no wind, for example, air can sit stagnant in a leaky home for days. On the other hand, during a windy day in the winter, a leaky home effectually needs to be re-heated from scratch every few hours, which is a waste of both energy and money. So the best way to ensure that a home is both healthy, safe, and energy efficient is to air seal the home as well as possible, and to pair air sealing efforts with increased mechanical ventilation to make sure that air cycles in and out of the house at a healthy and consistent rate.

We almost always recommend a hear recovery ventilator (HRV) or energy recovery ventilator (ERV), even for old and leaky homes, as they are a far more reliable source of ventilation than the natural ebbs and flows of air that enter the home through the basement and other air leaks. Even if you happen to live in an old 1700's cape or farmhouse, a heat recovery ventilator can be a wise choice, as they are typically more cost effective than dehumidifiers and safer than bath fans and range hoods.

Ventilation standards like ASHRAE 62.2 are largely designed for newer, very energy efficient buildings that have very little air leakage. Still, they can be a good guideline for achieving healthy ventilation and safe indoor air quality in any building. Our process takes into account ASHRAE and other guidelines (including the EPA's recommendation of an air change rate of .35 ACH) while performing building performance upgrades to ensure that your home is safe and healthy.

The best thing you can do as a homeowner to ensure that your home is as energy efficient and as healthy as possible is to talk to your home energy auditor about where you should focus your home improvement efforts. But as a basic premise, as the mantra goes, "seal tight, and ventilate right."