Caulk now, save money in winter

August 21, 2008

Given the rising costs of everything, what can I do to use less energy this winter? I have a heat pump and my home seems to have plenty of insulation.

Summer is an ideal time to tackle outdoor home maintenance, including weatherizing.

You write that your house has “plenty of insulation.” Even well-insulated homes can waste energy through air leaks. Invisible leaks cost money in winter as warm air escapes and cold air enters. A weatherization professional can perform a blower door analysis to locate the leaks. By depressurizing the home with a giant fan, the test clearly shows where air is entering.

Obvious spots for air leaks are around doors and windows, where the siding meets the foundation, and where two different siding materials meet, such as next to a chimney. Other spots are where utilities enter the home, and around recessed light fixtures, ceiling exhaust fans and furnace flues.

You can seal small leaks with inexpensive caulking that comes in disposable cartridges. When applied with a caulk gun it forms a flexible seal between the two surfaces when the gap is less than one-quarter inch wide. Caulk is available in silicone, rubber, latex and oil-based materials. Read the product label to determine which is correct for your application.

Start by cleaning the area to be caulked, removing old paint and caulk. Follow the instructions on the tube and do not cut too large of an opening in the tube. It’s easy to shoot too much caulk into the gap and create a mess. It’s best to draw a thin bead of caulk in a continuous stream. Push the caulk gun away from you and it will smooth the bead as you go.

Into the gap

Expandable spray foam is also available in aerosol cans. It expands after being sprayed into the gap. Foams are available in polyurethane and, more recently, water-based latex. Polyurethane is good for larger cracks, but be careful not to shoot too much foam into the gap. It can expand up to more than 200 times in volume – way more than you may need. We heard from one customer that the foam expanded so much it bowed the door frame, making the door unusable. Some window manufacturers will void the warranty if you use foam around their windows. The newer latex foams expand less and offer easy soap and water cleanup as well.

Whatever you use, if done correctly your home will be more energy efficient and more comfortable this coming winter since you’ll be eliminating drafts as well as keeping heat inside.