The answer in a one word is "control."

I just wish I had a nickel for every time this question gets asked. It does seem counter intuitive to block air and then add air. BUT if the air you’re blocking is too much for the house (almost always the case) and comes from the mold and rat infested crawl space, attic or garage (almost always the case) then you do want to block it. You want to control how much air to bring in and you want to bring it in from a clean and safe source (i.e. outside)

Picture yourself with a big easy chair watching TV and relaxing in the crawl space. It's not a pretty picture, and it is not where you want to hang out or where you want to get the air for yourself or our family.

Most homes leak far in excess of the required amount and they leak the air that is often times the most expensive, like through the heating ducts or air conditioning vents. Have an expert calculate your leakage and ventilation requirements then seal up the house and install a quiet (less than 1.5 sones) efficient fan. Put it on a programmable timer or motion sensor and breathe deep knowing you have the answer ready when your buddy comes in and says, "Why did you seal up the house and then add a fan?"

Regards,

Mark Rector
Owner
Trius HPC