Air sealing is a process of minimizing the movement of air in and out of your home. This can help your furnace and air conditioner stay balanced while lowering your energy costs.
Air sealing closes gaps, cracks, and other imperfections in a building envelope such as those around windows and doors. Many homeowners realize enough savings on heating and cooling to cover the cost of this service within a year or less.
Insulation
When outside air leaks into a home through cracks, holes, and penetrations for plumbing, wiring, recessed lights, and ductwork, it wastes energy that could be used to heat or cool the space. In addition, those leaking spots can bring in pollutants, allergens, and moisture that can negatively impact indoor air quality. Proper air sealing plugs these holes, helping to improve comfort and indoor air quality.
A well-sealed home also helps to prevent unwanted water vapor infiltration, which can lead to mold, condensation, and rot. This makes it a key part of any comprehensive moisture control strategy for your home.
It is important to understand that air seals and insulation work together—they are the yin and yang of a home’s performance. A home that is properly insulated but not air sealed will continue to have random air infiltration and may struggle to keep conditioned air inside.
Air sealing can be done using caulks, spray foam, metal flashing, and weather stripping, depending on the problem area. A Residential Registered Vendor can test the leakiness of your home with a blower door and other diagnostic equipment, and then recommend the best air-sealing products for your home. They can also install a variety of energy-efficient insulation types, including blown-in and spray foam. When combined with effective air sealing, proper insulation can significantly reduce heating and cooling costs.
Air Sealing
Air sealing keeps conditioned air inside the house and outside air out, saving energy bills, increasing comfort and improving indoor air quality. It is often the first step before adding insulation, such as blown foam or fiberglass. It addresses leaks around windows, doors, vents, fireplace flues and plumbing and wiring protrusions into wall and ceiling cavities. Leaks can also pull moisture into building cavities — a problem that often leads to mold and wood rot. Air sealants, like caulk and weather stripping, block gaps and cracks that allow air to move through a building envelope.
In addition to reducing heat flow in and out of the house, a tightly sealed building envelope can significantly reduce humidity levels and create a healthy indoor environment. It is important to remember, however, that while insulation and air sealing work well together, they must be installed as a whole-house system – not as stand-alone upgrades.
A poorly insulated home, even with good air sealing, can still be plagued by high energy bills and a lack of healthy airflow. Properly insulating attics, floors over crawl spaces and basements is critical to addressing the issue. Air sealing, coupled with proper insulation, is the best one-two punch for lowering energy bills, improving durability and creating a healthier indoor environment.
Energy Efficiency
Adding insulation and air sealing together offers the best solution for improved energy efficiency in homes. Together, these systems help keep conditioned air inside and outside air out, thus reducing energy waste and providing many benefits including reduced energy bills, better indoor comfort, enhanced home health, prevention of moisture problems (wood rot, mold), extended HVAC lifespan and sustainability.
In the United States, up to 30% of heating and cooling energy is lost through leakage points in a building envelope including windows, doors, vents, fireplace flues, plumbing and wiring protrusions into walls and ceilings, and more. Air sealing keeps conditioned air in and outdoor pollutants like carbon monoxide out, while also helping to prevent moisture problems that lead to wood rot, mold and pest intrusion.
The most common places where air leaks in and out of a home are around windows, doors, basements, attics and crawl spaces. However, there are many other areas that could benefit from air sealing such as gaps in floorboards, caulking around window casings, and cracks in walls and corners. A good place to start is with any area of your home that you feel drafty or has uneven temperatures. Air sealing and insulation work well together, so it is often best to air seal before adding insulation. In a new home, ideally, a combination of insulation and air sealing is used during construction.
Indoor Air Quality
Air sealing is a component of insulation that works to minimize the movement of air into and out of a home. It improves the performance of fiberglass, cellulose and mineral wool insulation by stopping air and moisture vapor from flowing through wall cavities and crevices. Air seals also work to prevent conditioned air from escaping the house, thereby reducing heating and cooling costs.
The best places to start when looking for areas that need to be air sealed are doors, windows and basements. These are the areas of a home that leak the most air and thereby waste energy. Typically, they also are the source of moisture infiltration. Prioritizing the areas to seal first is an important step from a time and budget standpoint, and it’s usually possible to find a quick fix, such as caulking around windows or wrapping them in shrink film, that will help homeowners to save energy, increase comfort and make their homes safer.
Before beginning an air sealing project, it’s important to test the current level of leakage with a blower door. This will tell the homeowner how much improvement they can expect to see. It will also identify combustion safety issues, such as backdrafting that can poison a household with carbon monoxide. A professional should be hired to address any combustion safety issues before or in conjunction with an air sealing project.