How to Stop Air Leaks in the Home and Save Money

Caulk windows inside and out to eliminate air leakage.

Small cracks and crevices throughout the home can allow air to flow in and out, interfering with the efficiency of central and window air and heat units. Hot air seeping in or air-conditioned air leaking out in summer, or cold air leaking in and warm air flowing out in winter can add significantly to your energy costs. The cost and amount of materials you will need to seal leaks in your home depends on the number and type of air leaks you have. Air leaks can be difficult to pinpoint, but it is worth the effort.

Things You'll Need

• Scissors or utility knife
• Safety goggles
• Breathing mask
• Heavy work gloves
• Damp sponge or caulk smoothing tool
• Duct tape
• Plastic garbage bags
• Ladder or step stool
• Outlet insulators
• Light-switch insulators
• Latex or acrylic caulk for windows and doors, white, clear or tinted
• Caulking gun
• Foam insulation tape or other self-adhesive weatherstripping
• Roll of attic insulation
• Spray-on foam insulation
• Screwdriver
• Outlet insulation kit
• Light-switch insulation kit

Instructions

Windows and Doors

1. Install a tube of caulk in the caulk gun and use the utility knife or scissors to cut off the tip. Cut the tip at an angle about 1/8 of an inch down. Check the tube's nozzle to be sure it is open. If you will need a wider bead of caulk, cut the tip farther down to make a larger opening.

2. Do the interior of the windows and doors first, since gaps, holes, cracks and crevices are generally easier to spot on the exterior framework. Lay the tip of the caulk tube along the line where any parts of the window or door frame and jamb meet. Squeeze the trigger on the caulk gun until the caulk begins to extrude from the nozzle, and slowly apply an evenly thick line of caulk along every seam.

3. Smooth the caulk bead with the sponge or smoothing tool so that the seam is completely sealed, with good adherence to the surfaces. Don't forget to caulk the seam where the frame meets the wall. Repeat on all windows and doors.

4. Caulk the threshold on all exterior doors using the same method as for windows and doors. If white caulk is not suitable in some areas, use a clear or tinted caulk to match your decor.

5. Go outside and caulk the exterior sides of the windows and doors, sealing all seams in the frameworks and jambs. Apply insulating tape or weatherstripping around the edges of the door frame that meet the door itself and along the base of the window, if needed.

Under Cabinets

1. Check the pipes inside the kitchen and bathroom cabinets. A surprising amount of air leaks in around pipes beneath the kitchen and bathroom sinks and pipes that enter the home from outside.

2. Wrap a plastic garbage bag around the pipe just behind the entrance to the hole and use the duct tape to hold the bag in place. Put on goggles and breathing mask, and spray a light coating of expanding foam insulation over the sealed hole. This insulation is not flexible, so do not spray the pipe with it or spray too close to the pipe. The spray foam will help hold the plastic in place and seal the edges of the hole to the plastic.

3. Use insulating foam tape around the pipe at the entrance to the hole if the gap is too large for caulk and too small to bother with plastic bags and spray-on foam insulation. Wrap the pipe just in front of the hole and wind the foam tape a second or third time, if needed, to fill the gap.

Attics

1. Apply foam insulation tape or weatherstripping to the attic access door frame so that the door seals tightly when shut.

2. Wearing goggles, breathing mask and gloves, shift insulation strips aside on the attic floor to check for leaks. Caulk the seams or use spray-on expanding foam insulation to close gaps and crevices, then put the insulation back in place.

3. If necessary, replace damaged strips of insulation with new strips or add a second layer. Use the sharp scissors or utility knife to cut strips from the fiberglass attic insulation roll to fit snugly between the rafters.

4. Check joints and seams on all exterior walls of the attic for leaks. Caulk small leaks or apply wall insulation. Fill larger holes and crevices with spray-on expanding foam insulation.

Light Switches and Electrical Outlets

1. Turn off electrical power to each room you work in. Use the screwdriver to remove light-switch covers and electrical-outlet covers. Set these aside, taking care to keep the tiny screws with the covers.

2. Open the light-switch insulation kit or electrical-outlet insulation kit and install, following manufacturer's instructions. Walls are excellent conduits for air circulation, so installing insulation behind switches and outlets on interior walls can stop small air leaks.

3. Restore power to the room you were working in and test the switches and outlets to make sure they are still working properly. Repeat in each room.

Tips & Warnings

• Plan your work. Locate and list or map the leaks you want to seal, making notes on what items you will need to accomplish the task. Assemble all of your tools and sealants before beginning this project.

• Use extreme caution when working with spray-on expanding foam insulation. Always wear a good-fitting mask. If this product is inhaled, it will expand inside your lungs, nose or mouth, which can be fatal.

References

• Energy Star: A Do-It-Yourself Guide to Sealing and Insulating With Energy Star
• U.S. Department of Energy; Air Sealing; February 2000
• Energy Star: Air Seal and Insulate With Energy Star
• U.S. Department of Energy: Weatherstripping; February 2011

Resources

• Energy Efficiency Arkansas; Locating & Sealing Air Leaks
• U.S. Department of Energy; Do-It-Yourself Home Energy Assessments; February 2011
• U.S. Department of Energy; Home Energy Assessments; February 2011