The Importance of Air Sealing Your New Home

Learning how to properly air seal your home is extremely important for maximizing efficiency. This article explains how to properly go about sealing your home.
learn how to properly air seal a home

learn how to properly air seal a home

Figure A

A "leaky" house causes higher energy bills and allows excess moisture and contaminants to enter the home. The places where air leaks into a house are often hidden from view. In this segment, a Georgia builder (Hedgewood Properties) demonstrates the best strategy to reduce air leakage as much as possible and to provide controlled ventilation with fresh outdoor air. Eliminating gaps in the building envelope reduces air leakage from the areas such as windows, floor and wall joints — even fireplaces. You'll see the areas sealed and the materials used by builders to keep the house from being leaky while increasing comfort for the homeowners.

The Importance of Air Sealing Your New Home

"Air sealing a house increases your comfort by reducing the drafts in a house," Rob Johnson, energy efficiency consultant for EarthCraft? House, said. "And by reducing the cycle time that your heating and cooling systems are going to run."

By air sealing the home the amount of humidity that enters will also be reduced, which is a big factor in the comfort level of a home.

A drafty house is more than just a waste of natural resources — it also means higher energy bills. You'll lower energy bills automatically by air sealing due to the fact that there should be less leaks in and out of the house.

Robin and Terry Sterck were impressed with how air-tight their Hedgewood Properties house in Georgia. "We walked around and noticed that they had caulked where the cement meets the wood — the foundation," Robin said. "We'd never seen anything like it."

"Ideally you want to air seal at the framing stage," Johnson said, "after all the mechanical equipment is gone." This includes sealing all the electrical, plumbing, etc. and the next step is to "foam" all of the penetrations that enter and exit the house.

Sealing up joints where air infiltrations occur is a tricky business since leaks are "usually" hidden from view. "Air infiltration is all the air leaking into your house through all the different pathways, whether it's a cracked open window, around the trim of a window that hasn't been sealed properly," Johnson said. "Air infiltration can simply be under a doorway where there's not a sweep installed or the threshold isn't adjusted properly."

Common infiltration paths include access to the attic and any air that can enter the house's envelope, and simply insulating the envelope (or shell) isn't enough. In fact, the ability of insulation to perform is almost cut in "half" if you don't air seal first, according to Johnson. "One of the most important steps in the process," he said, "in making your house energy efficient as well as comfortable is to air seal the house first."

Note: The insulation contractor does all the air sealing. Generally a builder or independent consultant will inspect the house after the air sealing has been completed.

"The insulation doesn't typically stop all of the air infiltration," George Del Valle, an insulation contractor, said. "So you want to do everything you can to stop that air from coming in." And it's vital to do the extra measure of air sealing before the house is built — not after because it becomes too difficult and costly due to access issues.

  • Three high-quality materials are used to air seal a home:
  • High-quality acrylic-latex caulk.
  • Fire-rated caulk.
  • Expandable polyurethane foam for the larger gaps.

Note: Foam is used in areas that are too wide for the caulk. If the area is wider than a 1/4" the caulk can fall out of the groove. The acrylic-latex caulk is for all the gaps that are small enough for the caulk to function properly such as the base plate and the seam between the floor and wall, and the fire-rated caulk is non-combustible and for any areas where wires penetrate through base plates, walls, etc. (This is a new national code that has been implemented recently.)

Hedgewood Properties guarantee that the homes they build have been sealed properly. "It made me feel more secure about making the choice in choosing Hedgewood. That's not something that a homebuilder has to do," Terry said.

It seems obvious that the gaps and crevices in a house should be sealed, but most builders have just recently started utilizing the air sealing process for new homes.

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