Weatherize Your Home to Lower Your Bills

DOE suggests checking around walls, ceilings, windows, doors, lighting and plumbing fixtures, switches and electrical outlets for gaps, worn caulk and weatherstripping, and doors and windows that don't close tightly. On a windy day, carefully hold a lit incense stick near likely leaks and watch for the smoke to waver.

DOE explains that caulk is for cracks between parts that don't move (like window and door frames), and weatherstripping is for parts that move (like doors and operable windows).

• Caulk gaps around window and door frames and where pipes, wires and ducts pass through walls, floors and ceilings.
• Weatherstrip doors and windows; add a door sweep to the bottom of exterior doors.
• Install foam gaskets behind outlet and switch plates on exterior walls.
• Use foam sealant on larger gaps around window trim and baseboards.
• Check that fireplace dampers close properly.
• Leave flues, furnaces and gas water heater vents to a professional.

ENERGY STAR's Seal and Insulate guidance lists simple fixes like weatherstripping and caulking and bigger jobs like sealing attic leaks and adding attic insulation, and it publishes recommended insulation R-values by climate. It's usually easiest to seal attic air leaks before adding insulation on top. Wear protective gear, watch your footing on joists, or hire a pro.

• In cold weather, DOE suggests tight-fitting, insulating window shades and opening curtains on sunny south-facing windows during the day.
• In hot climates, DOE suggests window films on east- and west-facing windows to reduce solar heat gain.
• Low-e storm windows are a lower-cost alternative to replacing windows.
• Caulk and weatherstrip existing windows before considering replacements.

DOE recommends setting your water heater to 120°F, a temperature it calls safe for most people. If your dishwasher has a booster heater, 120°F generally works; check its manual. DOE also suggests insulating hot water pipes and, if your tank is warm to the touch, insulating the tank per the manufacturer's instructions.

ENERGY STAR says that in a typical house with forced-air heating and cooling, about 20 to 30 percent of the air moving through the ducts is lost to leaks, holes and poorly connected ducts. For DIY, ENERGY STAR suggests sealing leaks with mastic sealant or metal tape (never duct tape, which it says isn't long-lasting) and insulating the ducts you can reach in attics, crawlspaces, basements and garages. A contractor can test and seal ducts you can't reach.

ENERGY STAR says you can save as much as 10% a year on heating and cooling by turning your thermostat down 7°–10°F for 8 hours a day in fall and winter, and up in spring and summer. A programmable or smart thermostat does it for you. If you'll be away in cold weather, the Red Cross advises not going below 55°F to protect pipes.

• DOE says a ceiling fan lets you raise the thermostat about 4°F without losing comfort. Run it counterclockwise in summer, and turn it off when you leave the room.
• Close blinds and shades on sunny windows during the day.
• Keep the AC filter clean and the outdoor unit clear of debris.
• Keep AC drain lines and drip pans clear (EPA) to avoid moisture problems.

Many utilities offer free or discounted home energy audits (also called energy assessments). A professional audit can find hidden leaks, especially in the attic, that DIY checks miss. Call your utility and ask what it offers, along with any rebates for insulation, air sealing or efficient equipment. ENERGY STAR's rebate finder can also help.

The U.S. Department of Energy's Weatherization Assistance Program helps income-qualified households make energy-efficiency upgrades at no cost to them. It's run through states and local agencies, so eligibility and wait times vary. If you're struggling with bills right now, see our winter utility shutoff help and behind on utility bills guides.