New Home Infiltration
Air leaks are the largest energy wasters in most newly constructed homes. Efforts to create an air-tight seal around the home's interior during construction are among the most cost-effective measures that can be made. While leaks are fairly simple and inexpensive to seal during construction, they are almost impossible to seal later. Begin by asking your builder or insulation contractor to seal unnecessary leaks.
One of the worst offenders is the sole plate, the place where the walls meet the floor. A strip of insulation and a bead of silicone caulk applied to the sole plate prior to erecting the walls eliminates this major infiltration point. Over-sized holes cut for wires or pipes should be filled with caulk or foam insulation, and anywhere dissimilar building materials meet should be sealed. Don't forget electrical and switch-plate outlets. They should be sealed with foam gaskets.
Some people worry they will make their home too tight. While this is possible, it requires some real effort. According to ASHRAE's standard for indoor air quality, homes achieving fewer than .35 air changes per hour should have some form of mechanical heat recovery ventilator installed to provide fresh outside air without losing expensive heating or cooling. Well constructed, tightly sealed homes cost less to operate, and because they are not drafty, are more comfortable to live in.
Other points to address to block infiltration include:
Fireplaces - they should have glass fronts or glass fire doors. There should be an outside air source to supply combustion air. Chimneys should have tight-fitting dampers.
Kitchens and baths - exhaust fans should be installed to help remove moisture from kitchens and baths. These systems should have back draft dampers to prevent heat from being lost when the fans are not it use.
Recessed lighting - often referred to as "can lights," recessed fixtures must be airtight and rated for an insulated ceiling to avoid any fire hazard.
Outlets and switches - surprising amounts of air infiltration comes from electrical and telephone outlets along exterior walls. Again, foam gaskets should be inserted underneath the outlet cover to block infiltration.