We often get the question, “Won’t spray foam make my house too tight?” Our answer for this is to remember the saying, “Build them tight, ventilate them right.” In fact, most houses are not too tight – windows and doors leak plenty of air. Yes, urethane spray foam insulation will make your house tight, but that’s a good thing. We do recommend installing air-to-air exchangers (ERV or HRV) to allow stale air to be exchanged efficiently.
Even if you are using standard fiberglass insulation, it may be a good idea to add mechanical ventilation to your home for mold prevention. Controlled mechanical ventilation can improve indoor air quality.