The arrows represent common air leaks in a building, and their colors correspond to data in the chart at far right. Note that the leaks at the window represent those between the sheathing and the framing around windows (and doors). They are not those between the window unit and the rough opening. (It is assumed these gaps will be air-sealed without question.)

Air-sealing a home is fraught with difficulty. We've learned we need to do it: If done well, it has a positive impact on occupant comfort, building energy efficiency, and indoor air quality. The big questions always come down to how much (how tight) and where building professionals should focus their efforts.If you're building to Passive House standards, perhaps the answers are clear. How much? A lot; you need to get total air leakage down to 0.6 air changes per hour at 50 pascals of negative pressure. Where? Everywhere, beginning at framing.Framing a Passive House resembles wrapping holiday presents. You are...