Sealing Air Leaks

One of the best ways to upgrade your home to reduce your heating and air conditioning expenses is to do some simple home maintenance.

Stopping air leaks in a home typically saves 20 to 50 percent on your home's heating and cooling costs.

To control the ventilation rate, remove stale air and recover energy from the outgoing stale air, use an energy recovery ventilator.

Does your house have a fireplace, furnace or water heater that can possibly put carbon monoxide, nitrous oxides, and other dangerous products of combustion into your home? If so, use carbon monoxide monitor with a digital display to warn you if dangerous backdrafting (reverse flow) of a chimney occurs.

NOTE: For maximum safety and energy efficiency when burning fuel, use a power-vented or closed-combustion system.

Below are a variety of home tightening tasks that will save money, energy and make a home feel more comfortable. Don't be intimidated by this list or feel that everything on the list has to be done. Each task will help contribute to the overall savings and comfort of the home.

The Tools

Leakage Through Ceilings, Walls and Floors

• Electric outlets -- Install foam gaskets behind all the light switches and electrical outlet covers, even on interior walls. These simple foam gaskets help seal the holes created when the outlets and light switches are built into homes. Then use child safety plugs to keep the cold air from coming in through the sockets.
• Windows and doors -- Weather strip and caulk all visible cracks and gaps between non-moving parts of window trim, especially under the window sills. Replace broken glass and putty any loose windowpanes. Caulk around the moving parts of windows with a non-permanent caulk during the winter. This type of caulk can be easily removed in the spring.
• Wall Baseboards -- Use a clear siliconized acrylic latex to seal any visible crack or gap at the top and bottom of baseboards. Otherwise warm moist air will leak into the walls and up through the attic during cold weather.
• Other wall holes -- Seal around all ceiling fixtures, heat registers, medicine cabinets, bath tubs, kitchen cabinets, drains and water pipes where they pass through walls wall and any other holes in exterior walls.
• Fireplace Dampers -- Missing or poorly fitting dampers allow air to move freely up and down the chimney. Install a new damper or repair the existing one so it closes tightly.
• Recessed lights and bathroom fans -- Caulk around these from below with high-temperature flexible caulk.
• Air conditioners -- Remove window air conditioners before winter. If they can't be removed, seal up the area around the unit with removable rope caulk and add an AC window insulation blanket.

Monsters In The Attic and Basement

The attic and basement are the biggest air leak culprits in homes. Sealing up the air leaks in these two areas is the best guarantee for a comfortable home.

• Doors and hatches to the attic -- Weather strip the edges and insulate the backside of the attic door. Fold-down stairs can be covered with a lightweight box made of rigid insulation board.
• Holes in the attic floor -- Don't be surprised to find holes in the floor of the attic -- especially around the outside walls, ducts, recessed lights or near plumbing utilities and other outside penetration. Also, look for dirty spots in your insulation, which often indicates holes where air leaks into and out of your house. You can seal the holes by stapling sheets of plastic over the holes and caulking the edges of the plastic. Carefully check for these trouble spots.
• Around the chimney-- Any chimney that runs from the basement through the attic should be sealed at both the basement ceiling and attic floor by use of sheet metal or metal duct tape. Fire codes prohibit the use of combustible materials within 2 inches of chimneys.  NOTE: Fiberglass is not an effective air barrier.
• Around the sewer vent pipe -- A sewer vent pipe typically runs vertically from the basement through the attic and should be sealed at both the basement ceiling and attic floor by use of wood, sheet metal, or metal duct tape.
• Basement windows -- Use masonry caulk to fill any cracks where the frames of the windows are set into the walls. Windows that are not used for summer ventilation or as fire exits can be permanently caulked shut.  In the basement, you are likely to find air leaks around the windows, along the sill plate and band joists, and where the ducts pass through the basement ceiling.

Stop Drafts

Caulking also stops drafts and, therefore, makes the room feel more comfortable. This reduces the urge to reach for the thermostat and turn it up, which reduces energy consumption and cost.

Seal Your Home From Cold Air

Source: Energy Efficiency and Renewable Energy Clearinghouse http://eren.doe.gov/

Warmed air mixes with outside air through gaps in your home's thermal envelope ? exterior walls, windows, doors, the roof, and floors. Such air leaks can waste large amounts of energy.

Most experts agree that caulking and weather stripping any gaps will pay for itself within one year in energy savings. Caulking and weather stripping will also alleviate drafts and help your home feel warmer when it's cold outside. However, these two weatherization techniques can't replace the need for proper insulation throughout your home.

Assessing Air Quality

Because caulk and weatherstripping limit indoor-outdoor air circulation, you should assess your indoor air quality before you apply them. Some homes contain dust, mold, carbon dioxide, and other indoor air contaminants. Sealing air leaks in these homes, without proper ventilation, can also seal in their indoor air pollutants. Therefore, any plan to tighten the thermal envelope of a home should be accompanied by a look at your home's ventilation needs.

Read more about indoor air quality at: www.epa.gov/iaq/

Detecting Air Leaks

You may already know where some air leakage occurs in your home, such as an under-the-door draft that makes you want to put on socks. But you'll probably need to search to find the less obvious gaps.

Look at areas where different materials meet, like between brick and wood siding, between foundation and walls, and between the chimney and siding. Also inspect around the following for any cracks and gaps that could cause air leaks:

• On floor of attic (around chimneys, recessed lights, sewer vent pipe, etc.)

• Baseboards of interior and exterior walls

• Joints in the trim around doors and windows

• Electrical outlets and switches

• Pipe penetrations under sinks

• Electrical and gas service entrances

• Cable TV and phone line penetrations

• Outdoor water faucets

• Bricks, siding, stucco, and foundation

• Air conditioners

• Vents and fans

• Mail chutes

CAUTION: Tyvek or tar paper is used behind siding to provide a drainage plane where condensation can flow down to the ground. If the bottom of the siding is sealed, then the condensation will become trapped and encourage mold growth on the back of the siding.

On a cool, very windy day, turn off the furnace and water heater. Shut all windows and doors. Depressurize your home by turning on all fans that blow air outside, such as bathroom fans or stove vents. Then light an incense stick and pass it around the edges of common leak sites. Wherever the smoke is sucked out of or blown into the room, there's a draft. Or just turn on all your exhaust fans (don't need to turn off the furnace) and try one of these methods:

• At night, shine a flashlight over all potential gaps while a partner observes the house from outside. Large cracks will show up as rays of light. It's not a good way to detect small cracks.

• Shut a door or window on a piece of paper. If you can pull it out without tearing, you're losing energy.

For a more thorough and accurate measurement of air leakage, you can hire a technician to conduct a blower door test in your home. Blower doors are variable-speed fans with a frame and shroud that allows them to fit inside a variety of door frames. Pressure gauges determine airflow through the fan, as well as fan-induced pressure. The leakier a house, the more airflow required to induce a pressure difference. When used as a diagnostic tool, a blower door can also reveal the location of many leaks.

Caulk and Foam

You can use a caulking compound or a low-expansion foam to seal leaks in a variety of places throughout your home, including around windows and door frames. In addition to plugging air leaks. Caulk and foam can also prevent water damage inside and outside of the home when applied around faucets, ceiling fixtures, water pipes, drains, bathtubs and other plumbing fixtures.

Caulk forms a flexible seal for cracks, gaps, or joints less than 3/16-inch wide. Most caulking compounds come in disposable cartridges that fit in half-barrel caulking guns (if possible, purchase one with an automatic release). Some pressurized cartridges do not require caulking guns. When deciding how much caulking to purchase, consider that you'll probably need a half-cartridge per window or door and four cartridges for the foundation sill. Caulking compounds can also be found in aerosol cans, squeeze tubes, and ropes for small jobs or special applications.

Water-based caulk can be cleaned with water, while solvent-based compounds require a solvent for cleanup. Caulking compounds also vary in strength, properties, and prices.

One of the most popular types of caulk is clear siliconized acrylic latex that is warranted for 50 years and made by DAP. When applied, it is white and any excess can be wiped away with a damp cloth. When cured, it is clear and paintable.

Application

Although not a high-tech operation, caulking can be tricky. Read and follow the instructions on the compound cartridge. And save yourself some trouble by remembering a few important tips:

• Clean all areas to be caulked for good adhesion. Remove any old caulk and paint, using a putty knife or a large screwdriver. Make sure the area is dry so you won't seal in moisture.

• Hold the gun at a consistent angle. Ninety degrees is best for getting deep into the crack. You know you've got the right angle when the caulk is immediately forced into the crack as it comes out of the tube.

• Caulk in one straight continuous stream, if possible. Avoid stops and starts. Send caulk to the bottom of an opening to avoid bubbles.

• Make sure the caulk sticks to both sides of a crack or seam.

• Release the trigger before pulling the gun away to avoid applying too much caulking compound. A caulking gun with an automatic release makes this so much easier.

• If caulk oozes out of a crack, use a putty knife to push it back in.

• Don't skimp. If the caulk shrinks, reapply it to form a smooth bead that will seal the crack completely.

Weather Stripping

Weather stripping can seal leaks around movable joints, such as windows or doors. You need to choose a type of weather stripping that will withstand the friction, weather, temperature changes, and wear and tear associated with its location.

For example, when applied to a door bottom or threshold, weatherstripping could drag on carpet or erode as a result of foot traffic. Weatherstripping in a window sash must accommodate the sliding of panes-up and down, sideways or out. The weatherstripping you choose should seal well when the door or window is closed while allowing it to open freely.

Choose a product for each specific location. Felt and open-cell foams tend to be inexpensive, susceptible to weather, visible, and inefficient at blocking airflow. However, the ease of applying these materials may make them valuable in low-traffic areas. Vinyl, slightly more expensive, holds up well and resists moisture. Metals (bronze, copper, stainless steel, and aluminum) last for years and are affordable. They can also provide a nice touch to older homes where vinyl might seem out of place. You can use more than one type of weather stripping to seal an irregularly shaped space. Take durability into account when comparing costs.

Application

Weather-stripping supplies and techniques range from simple to the technical. Consult the instructions on the weather-stripping package. Here are a few basic guidelines:

• Weatherstripping should be applied to clean, dry surfaces in temperatures above 20 degrees F (-7 degrees Centigrade).

• Measure the area to be weather stripped twice before you cut anything.

• Apply weather stripping snugly against both surfaces. The material should compress when the window or door is shut.

Source: Energy Efficiency and Renewable Energy Clearinghouse http://eren.doe.gov/