Reducing air leakage can be the most cost-effective, energy-saving measure a homeowner can undertake; the leakier the home, the greater the savings. Typically it is more cost-effective to have a well-insulated, airtight house with mechanical ventilation than a poorly insulated house that relies on leaks and holes in the walls for fresh air. The cost of careful draftproofing and ample insulation is offset by reduced heating and cooling costs over the life of the home.

Did you see a building science or energy efficiency term you did not understand? Check out our glossary.