Air Sealing

Energy Assessments and Insulation Services

The most important part of any insulation project is air sealing. The terms “air sealing” means to plug up any places where air can move in or out of your home. Many leaks are found at cracks, small holes, and penetrations for plumbing pipes, electrical wiring, lighting, and ductwork. Combined, these leaks can add up to as much air loss as leaving a window open! It is easy to see how leaks can contribute to a home’s overall efficiency and have serious effects on utility bills and comfort.

Nearly every home we inspect could benefit from some additional air sealing. Even if you feel your home is too tight, it is better to control moisture and ventilation mechanically than to rely on the seasonal pressure changes to determine air flow.

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, while providing ventilation as needed for fresh air. In other words, “build it tight and ventilate it right.”

Why is Air Sealing Important

Added Comfort – Drafts felt in the cold season are often the result of unsealed gaps and holes. Sealing homes tightly typically results in fewer cold drafts.

Improved Indoor Air Quality – A tighter envelope reduces the amount of dust, pollen, humidity, and pests that can penetrate the home and helps improve indoor air quality.

Lower Heating and Cooling Bills – Air leakage and poorly installed insulation can waste 20 percent or more of the energy used to heat or cool a home. With effective air sealing and insulation, HVAC systems won’t have to work as hard.

Increased Durability – When warm air leaks through a home’s floors, walls, and attic it can come in contact with cooler surfaces and condensation can occur. Moisture in these materials can foster mold growth, ruin insulation, or even compromise the structural elements of the home. Reducing air leakage helps minimize moisture problems and increase the home’s long-term durability.

Insect and Rodent Control – Not many homeowners realize that they live with both bats and mice, they just never see them.  Mice gain access into the basement from holes in the box sills, and bats usually gain access through the soffit or roof.  When all the small holes in the walls and ceilings are sealed, it keeps them from entering the home and traveling via the interior and exterior walls.


While poorly sealed windows and doors can contribute to air leakage, the bigger sources are typically holes and penetrations through the home’s envelope that are hidden from view. These include penetrations for piping, wiring, lighting, and duct work as well as seams where materials join. It is easiest to seal these areas during construction because access is much more limited afterwards. Builders can use a variety of products to seal a home’s envelope, such as caulks, foams, gaskets, weather-stripping, and house wraps. For homes that are sealed very tightly, mechanical ventilation systems are available to provide a controlled amount of fresh air.



We treat every situation differently as each home is a unique structure with its own story. Following a thorough inspection (see our INSPECTION area for more info) we will prescribe the best solution for your home. Often this involves using an expanding foam to most cracks and gaps. In some cases, we may recommend another product in order to preserve an aesthetic look. We are much different than many other companies in that we take the time to clean the space we are sealing in order to get the adherence required.