Last week I discussed the types of foam and which to choose in, Closed-Cell Foam or Open-Cell Foam?
This week I want to talk about one of the key features of spray foam insulation, air tightness.
By using an insulation, that is an air barrier, as the primary building envelope component, you create tighter building envelopes and the resulting benefits of these spray foam insulation building envelopes includes increased control of interior comfort levels and lower energy cost.
When you talk to people about creating these tighter building envelopes, are you ever asked, “Don’t Buildings Need to Breathe?”
Me too.
Here is my answer:
No, buildings do not need to breathe, they do not have lungs. The people in the buildings are the ones that need to breathe.
For energy efficiency and interior comfort purposes, the best approach is to seal the structure as tight as possible, then take care of the indoor air from the inside out, with a proper air management system.
After sizing the mechanical system, there are several options for providing fresh air ventilation that range from a simple damper controlled inlet duct that is installed on the return side of the HVAC system, all the way to the high-end energy recovery ventilator, which will condition the supply air using energy from the exhaust air.
Besides, even if buildings needed to breathe, that’s not a very good justification to build leaky, drafty, inefficient structures.
The best in building science offers this adage,
“Build it tight and ventilate right.”
