Thursday, September 15, 2011

Eight Ideas to Seal Air Flow

Looking to save money this year in your Lexington MA home, try this quick and cheap eight ideas!

1. Insulate
Most recessed lights have vents that open into the attic, a direct route for heated or cooled air to escape. Many homes have up to 30 or 40 of these fixtures. Lights labeled ICAT, for "insulation contact and air tight," are already sealed; look for this label next to the bulb. If you don't see it, assume it leaks. An airtight baffle is a quick fix. Remove the bulb, push the baffle up into the housing, then replace the bulb.

2. Plug Cavities
Most homes have an inner skin of drywall or plaster between living space and unheated areas. But builders in the past often skipped this cover behind knee walls (partial-height walls where the roof angles down into the top floor), above dropped ceilings or soffits, and above angled ceilings over stairs.
Up in the attic, you may need to push insulation away to see if the stud cavities are open. If they are, seal them with fiberglass insulation stuffed into plastic garbage bags; the bag is key to blocking air flow. Close large gaps with scraps of drywall or pieces of reflective foil insulation. Once you've covered the openings, smooth the insulation back into place. To see these repairs in action, consult Energy Star's DIY guide to air sealing.

3. Close Gaps
Building codes require that wood framing be kept at least one inch from metal flues and two inches from brick chimneys. But that creates gaps where air can flow through. Cover the gaps with aluminum flashing cut to fit and sealed into place with high-temperature silicone caulk. To keep insulation away from the hot flue pipe, form a barrier by wrapping a cylinder of flashing around the flue, leaving a one-inch space in between. To maintain the spacing, cut and bend a series of inch-deep tabs in the cylinder's top and bottom edges.

4. Weatherstrip
A quarter-inch gap around pull-down attic stairs or an attic hatch lets through the same amount of air as a bedroom heating duct. Seal it by caulking between the stair frame and the rough opening, or by installing foam weatherstripping around the perimeter of the hatch opening. Or you can buy a pre-insulated hatch cover kit, such as the Energy Guardian from ESS Energy Products ($150).

5. Squirt Foam
Once the biggest attic gaps are plugged, move on to the medium-size ones. Low-expansion polyurethane foam in a can is great for plugging openings 1/4-inch to three inches wide, such as those around plumbing pipes and vents. A standard 12-ounce can is good for 250 feet of bead about half an inch thick. The plastic straw applicator seals shut within two hours of the first use, so to get the most mileage out of a can, squirt a lubricant such as WD-40 onto a pipe cleaner and stuff that into the applicator tube between uses.

6. Caulk
Caulk makes the best gap-filler for openings less than 1/4-inch wide, such as those cut around electrical boxes. Silicone costs the most but works better next to nonporous materials, such as metal flashing, or where there are temperature extremes, as in attics. Acrylic latex caulk is less messy to work with and cleans up with water.

7. Plug Gaps
Gaps low on a foundation wall matter if you're trying to fix a wet basement, but only those above the outside soil level let air in. Seal those with the same materials you'd use in an attic: caulk for gaps up to 1/4-inch wide and spray foam for wider ones. Use high-temperature caulk around vent pipes that get hot, such as those for the furnace or water heater. Shoot foam around wider holes for wires, pipes, and ducts that pass through basement walls to the outside.
In many older homes with basements, air seeps in where the house framing sits on the foundation. Spread a bead of caulk between the foundation and the sill plate, and along the top and bottom edges of the rim joist.

8. Tighten Up
In the main living areas of your home, the most significant drafts tend to occur around windows and doors. If you have old windows, caulking and adding new weatherstripping goes a long way toward tightening them up. Bronze weatherstripping lasts for decades but is time-consuming to install, while some self-stick plastic types are easy to put on but don't last very long. Adhesive-backed EPDM rubber is a good compromise. Nifty little gadgets called pulley seals block air from streaming though the holes where cords disappear into the frames. Weatherstripping also works wonders on doors. If a draft comes in at the bottom, install a new door sweep.

1 comment:

  1. great ideal, someone who want to seal air flow should read this.

    chimney pipe