The standard home laundry dryer vents outdoors via an exhaust duct. This duct is open to the outdoors, and it may be letting cold air into the home. That's because there is typically a flimsy flapper made of sheet metal on the outside of the vent to help protect against air infiltration. But over time dryer lint can accumulate at the vent opening, causing the metal flapper to stay open when it should close. Homeowners can invest in dryer seals that close the vent when the dryer is not in use. Not only does this prevent cold air from entering the house, but also it keeps out pests, like bugs and rodents.
Check pipes that exit the home, such as those that feed outdoor water spigots, as such pipes can let cold air back into the house. The same can be said for waste pipes. Also, check to see if pipes that connect to garages, basements and crawl spaces are not insulated. Use sealant around these pipes to block drafts into the home. Foam insulation can be sprayed into small crevices, where it will expand and harden, blocking off air access. These damp, cool spots are also great places for insects to enter the home. Sealing drafts also may prevent bugs from entering the home.
Although fireplaces often make for decorative and appealing accents to a home, many are not effective sources of ambient heat. They may draw more warm air out of the flue than they bring into the house. When a fireplace is not in use, air can rise out of the chimney and a draft can be felt in the home. Some studies indicate that an open damper on an unused fireplace, even in a well-insulated home, can increase overall heating and cooling energy consumption by 30 percent.