Inspect Windows and Doors to Eliminate Costly Air Leaks

Winter is here and so too are freezing temperatures. “It’s important for homeowners to check for air leaks or drafts in their home this time of year in order to save money and energy and keep the frigid air out,” said Scott Cline, owner of J&B Construction. “According to Energy Star, ensuring your windows and doors are properly sealed is among the most cost-effective things you can do to conserve energy and increase comfort.” So if you feel there is a draft in your home, be sure to inspect both the inside and outside to locate costly air leaks.

When checking your home’s windows and doors for air leaks, start with a detailed visual inspection from both the inside and outside. “On the exterior, you should look for areas where the old caulking has failed, revealing the gap between the window or doorframe and your home’s siding,” said Scott.

If your home has old single-paned windows, be on the lookout for damaged glazing, which is the hard putty that holds the individual panes of glass in place. “If the entire perimeter of each window and door is not sealed tight against water and air infiltration, your home is vulnerable to heat loss,” he said.

From the interior, inspect the threshold under each door, looking for daylight or other obvious signs of an opening that is too big and needs to be sealed shut. “Make sure the weather stripping around the windows and doors is in good condition, making note of any damaged weather stripping that needs to be replaced,” Scott said.

Although many problem areas are obvious, keep in mind some air leaks are not easily detectable. One way to reveal air leaks is to conduct a “smoke test,” which requires all windows and doors in the home to be closed and any combustion appliances, such as a furnace or water heater, turned off. “Next, turn on the kitchen and bathroom exhaust vents, which will create a negative pressure in the house that will suck outside air into the home through any crack or opening,” Scott said. “Now you can check for air leaks by holding a lit incense stick close to the spaces around the edges of windows and doors, looking for a noticeable change in the smoke rising from the lit incense stick. If there is an air leak, the smoke will waiver and be drawn inwards by the outside air that is finding its way into your home. If the smoke remains undisturbed, you can assume that there are no air leaks in that specific area.”

Another option for detecting air leaks is using an infrared thermometer, which is a non-contact thermometer that can measure the ambient air temperatures around window and doorframes. In areas where cold outside air is leaking into the home, the thermometer will register a colder temperature, indicating a vulnerable area that could be wasting energy and money.

“If you don’t feel comfortable determining if your home has air leaks, you can hire a professional energy auditor to conduct a ‘blower-door’ test on your home,” he said. Similar to the smoke test, a blower door test can assess the air tightness of the home and detect air leaks. During this test, a specialized fan is attached to the home’s doorframe, which then pulls air out of the home, resulting in a lower interior air pressure. Once the fan is stopped, the higher air pressure outside the home tries to find its way back into the home through cracks or crevices. A smoke stick is then used to locate those areas that are leaking and vulnerable to heat loss. “This test is usually cost-effective, and in many areas, homeowners can apply for an energy audit from the local utility company.”

Once air leaks have been discovered, it is imperative that they be sealed. “More often then not, a fresh layer of exterior-grade caulking will adequately seal any gap or crack that is causing problems,” Scott said. “New weather stripping or an adjustable threshold can also help to seal gaps around doors. Remember, the goal of this project is to discover all of the air leaks around your home so that you can seal them tight, which should result in a more comfortable and energy efficient home this winter.”