When searching for the perfect home, it is highly unlikely that eager shoppers—especially in this seller's market—will be asking many questions about air leaks. To a homebuyer more interested in the building's finished basement, new deck, and proximity to a preferred school district, air leaks may seem like a minor issue. However, home inspectors understand that gaps in a home, even small ones, can cause major issues if not taken care of.
Air leakage in a home can cause serious moisture-related problems as well as affect indoor comfort and energy costs by letting in hot air in the summer and frigid air in the winter, or allowing damp bathroom air to penetrate a cool attic when the thermometer plummets.
Having the home checked for air leakage is one of the many reasons to hire a home inspector to perform a complete foundation-to-roof inspection before you place a bid on a property. In most cases these leaks can be easily remedied, saving you money on your utility bills and preventing potentially high-cost repairs that can result from undetected moisture damage. Further, the inspection provides the peace of mind that you're leaving no stone unturned before making perhaps your largest investment. As we discussed in our previous two posts on attic inspections, sealing attic leaks is an important step that should be done in conjunction with installing proper venting and sufficient insulation to ensure the home's health and your family's comfort. It is recommended to seal air leaks prior to adding insulation.
Your home inspector will be able to report on visible gaps and cracks that may be permitting the unwanted movement of air and moisture. Here are just a few of the many common areas for home air leakage that have been observed by the home inspectors at a-pro over the last 27 years:
Windows and Doors: According to the U.S. Department of Energy's “Energy Saver” program, heat gain and loss through windows account for up to 30% of residential heating and cooling energy use. Your inspector will report on gaps (e.g., cracks around molding) in windows that should be caulked or weather-stripped, including problems with basement windows. Similarly, exterior doors that have not been sealed or have aging, poorly installed, or absence of weather-stripping can have significant air leakage problems. Often air will leak under the door's threshold if it has been incorrectly installed.
Basement Rim Joists: Gaps and cracks in the basement's rim hoist (perimeter framing that sits on top of the foundation) can be a profound source of air leakage in a home—even more egregious than a home's drafty windows in some cases. Further, this becomes a prime entrance point for bugs and rodents to find easy access into your humble abode. In addition to sealing up this area, insulation is often recommended to prevent energy loss and increase home comfort levels. There are many other areas in a basement where there may be air leakage issues, including gaps between the sill plate and foundation; venting ducts; and plumbing, electrical, and gas penetrations.
Skylights: Poor installation is often the cause of air leaks around the perimeter of a skylight. Cracked glass is an obvious concern.
Fireplace: Your inspector will check to see if there is a working damper controlling the flow of air within the chimney.
Walls: Your inspector will note cracks and gaps where walls meet and where walls meet the ceiling. Further, holes in exterior walls will be noted. These may include gaps around exhaust fans, electrical outlets, light fixtures, plumbing penetrations, clothes dryer ducts, etc.
Electrical Wiring and Plumbing Penetrations: It is not uncommon to find gaps, sometimes quite large, where there are electrical wire and pipe penetrations. Gaps around electrical receptacles, switches, and fixtures may also be noted. Gaps around recessed lighting are frequently one of the worst offenders when it comes to air leakage in a home.
Attic Access Door: Gaps around attic hatches or pull-down attic stairs can cause significant air leakage if not sealed with caulk or weather-stripping.
Exhaust Fans: Improper sealing of kitchen and bathroom exhaust fans can result in air leakage and potential energy loss. Your inspector will note if these devices have gaps around the fan box or ducting.
Other areas where air leakage is common include open stud cavities and floor gaps in finished attics, kitchen soffits and dropped ceilings, ductwork, whole-house fans, behind or under attic kneewalls, baseboards, crawl spaces, flue or chimney shafts, utility chases, and walls between the garage and living space.
As an added service, many A-Pro home inspectors perform Thermal Imaging Inspections which can locate the sources of air leaks in addition to identifying areas of inadequate insulation.