A poorly insulated or drafty home is the equivalent of turning the air conditioner on and opening a window. Few people realize the important role that air sealing a home plays in saving energy and improving the overall comfort of the home during the summer and winter. If you’re wondering how to air seal a house, or just want to find out what to expect from a professional hired to do the job, the following guide offers a general overview of how to air seal a house.
The importance of learning how to air seal a house
You can have the most efficient equipment, but it won’t matter if you’re letting all of that air escape to the outdoors. Even a well-insulated home will lose large amounts of heat and conditioned air if it’s not well sealed. Sealing your home can save up to 20 percent per year on your energy bill. In addition, a well-sealed home will feel less humid and have better indoor air quality.
Common areas to check for air leaks
- Attic spaces and knee walls
- Windows
- Doors
- Ducts
- Dropped ceilings/soffits
- Recessed lights
- Common walls
- Fireplaces/flues
- Places where wiring, plumbing or vents protrude through exterior walls
How to detect air leaks
There may be areas of your home where you can actually see or feel the air moving through places where it shouldn’t be. For example, you may feel the drafts around the door jams, or see the curtains moving next to leaky windows. You may also see tell-tale signs of air leakage, such as dirty insulation or cracks in the plaster or drywall. However, some leaks are very small and will only be detected with special testing. You can perform many of these tests yourself with materials you already have on hand, or you can hire a professional to complete an energy audit.
Blower door test. Negative pressure is created inside the house by closing up the house and pulling the air from the home with a special fan. A smoke stick can be used to detect leaks throughout the house.
Duct pressurization. A fan is inserted into the ducts to measure the rate of air leakage. This can be done in a similar manner to the blower door test.
Infrared scanning. A special camera takes a picture of the temperature of your house. The scan is often done in conjunction with the blower door test. Large differences in thermal energy within a house can indicate insulation issues.
Carbon monoxide testing. Elevated carbon monoxide levels can indicate problems with ventilation that need to be fixed before you start to air seal the home.
Ventilation and indoor air quality
Understanding proper ventilation is important when you’re learning how to air seal a house. Older homes can have issues with inadequate ventilation that need to be addressed before you begin your repairs. By sealing up existing leaks, you may be eliminating the natural escape routes for harmful gases such as carbon monoxide and other indoor air pollutants. A contractor can install a whole house ventilation system that will improve your indoor air quality and allow you air seal your home safely.
How to air seal a house
While this is by no means an exhaustive list, it does provide general recommendations for how to air seal the most common problem areas within your home. By addressing these areas, you will see significant energy savings.
- Windows, doors, and attic access. Add weatherstripping, caulk or spray foam (depending on the situation) to tightly seal any gaps that may be leaking air.
- Joist spaces, attic ceilings, knee walls in finished attic rooms, dropped ceilings and soffits. Pull back any existing insulation and fit these spaces with a rigid roam board sealed around the perimeter with a bead of caulk to block the air flow. Dirty insulation can be reused as long as it’s not wet or moldy.
- Ductwork. Reconnect loose ductwork to the registers. Seal any leaks with duct mastic or high-quality metal tape. Avoid using standard duct tape because it doesn’t provide a long-term solution.
- Recessed lighting. If possible, replace old recessed lighting with new, airtight, energy-efficient models.
- Furnace flues and fireplaces. Care needs to be taken to ensure that the insulation does not come into contact with anything combustible. Aluminum flashing can be used to build a dam around the flue that should be sealed with heat-resistant caulk before insulating.
A blower door test and carbon monoxide test should be conducted following the completion of any insulation work to evaluate the effectiveness of the repairs.
Some homes may need significant upgrades before you can begin the air sealing process. At James Lane, we can help you evaluate your home, answer your questions about how to air seal a house, and support you through the process. Our qualified technicians have been helping residents of Wichita Falls and the surrounding areas improve their comfort and increase energy savings for more than 50 years.
