I'm having a difference of opinion with one of my favorite hvac contractors, a plumber named Herb. The subject of our disagreement is whether the 20-year-old electrically heated apartment buildings we are modernizing are too tight. A too-tight house can lead to a buildup of airborne toxins, causing health problems for the occupants and liability for the contractor. It can also result in mildew and condensation problems. I believe these buildings are so tight that they need central ventilation systems to prevent these problems; Herb thinks I'm out to lunch. Who's right? The answer, I think, depends on just how tight the house is. And to find that out, you need a blower door. What It Is A blower door
