Air leaks are often found at cracks, small holes, and penetrations for plumbing, wiring, lighting, and ductwork. Together, these leaks can add up to as much air loss as having an open window!
Sealing a home’s envelope – its exterior walls, ceiling, and floors – is an important step in controlling the indoor environment and lowering energy bills. The goal is to reduce air leakage as much as possible. In the same time it’s essential to provide ventilation for fresh air and making that upcoming moisture like condensation can dry.
Builders can use a variety of products to seal a home’s envelope, such as caulks, foams, gaskets, weatherstripping, door sweeps, and house wraps. For homes that are sealed very tightly, mechanical ventilation systems are available.
Air leakage and improperly installed insulation can waste 20 % or more of the energy you pay to heat and cool your home. An essential step for improving energy efficiency is the proper sealing of air leaks throughout the building to stop drafts. Some are easy to identify, others are more difficult to find and fix, for example in the attic, basement, and crawl spaces. We use caulk, spray foam, or weather stripping.
After the leaks are sealed, high performance insulation is added to the walls, attic, basement, and also the duct work of your HVAC system.
Benefits of Air Sealing
- Improved Comfort. Drafts felt during the winter are often the result of unsealed cracks and holes. Sealing homes tightly typically results in fewer drafts and less noise.
- Lower Utility Bills. Air leakage and improperly installed insulation can waste 20 percent or more of the energy used to heat or cool a home. With effective air sealing and insulation, heating and cooling systems will not need to work as hard.
- Improved Indoor Air Quality. A tighter home envelope reduces the amount of humidity, dust, pollen, and pests that can enter the home and helps improve indoor air quality.
- Increased Durability. When warm air leaks through a home’s floors, walls, and attic, it can come in contact with cooler surfaces where condensation can occur. Moisture that occurs in these construction assemblies encourages mold growth, ruins insulation, and even compromises the structural elements of the home. Reducing air leakage helps minimize moisture problems and increase the home’s durability.
The next step of ZNE is installing an appropriate HVAC system.