Unless you're talking about beers flowing out of your kegerator, drafts in your house are generally considered a bad thing. There are two main reasons why stopping drafts in your house is important:
• They make your living quarters uncomfortable
• They drive up your utility bills.
The most likely source of drafts coming into your home is gaps around windows and doors. Sometimes the area around windows and doors isn't insulated to begin with while other draft causes could include missing siding, gaps that have opened over time, or insulated glass that has that has sprung a leak. In general, as a home wears, the more likely it is to develop drafts and air leaks – which is why older homes fall prey to this more often than newer builds.
Windows and Doors – Not the Only Source of Drafts in Your Home
Diagnosing a window or door draft does not take elaborate troubleshooting. You'll be able to know if your windows or doors have developed drafts just by wetting your hand and putting it in front of them, especially around the perimeter, when it is cold outside. If you feel cold air, install (or replace) weatherstripping where the door and window meet the frame. The door sweep at the bottom may also need to be replaced. If the walls around the windows and doors feel cold to the touch, you can also pop off the surrounding trim to see if the jambs are indeed insulated.
Air leaks can develop in numerous other places in your home, however – some of which aren't always easy to detect. You could be siphoning heated or cooled air out of your home for years without really knowing it. Some of those major areas include:
• Attic hatch / pull-down stairs
• Wherever wiring or piping enters and exits the home
• Flooring above the basement
• Chimney flues
• Wherever two different materials meet on the exterior
The basic principles behind stopping drafts in these areas is covering up or sealing the air-loss area with insulation, caulk, or some other sort of protective barrier. Follow the specific recommendations for each section of the home.
The first thing to check is that your attic is properly insulated with cellulose fiber, cotton or fiberglass batts, or some other source of an insulating barrier. Note that some kneewalls in unfinished attics (side walls that support rafters in the attic) are left uninsulated because they aren't technically going into a living quarters. A cap or covering of insulating foam board should also be placed over the attic hatch, as it is a huge source of energy loss. Something to remember is that your unfinished attic still has outside air flowing through it via vents, normally roof (gable, cap, and/or ridge) and soffit or eave vents. You just want to prevent the household air from entering the attic and costing you energy.
Wiring and Pipe Entrances and Exits
Oftentimes holes for wires, pipes, dryer vents, and the like are cut larger so that these items can be easily affixed into place. This extra gap needs to be filled in, however, with either insulation, caulk, or spray foam.
Flooring above an Unfinished Basement
If your basement is unfinished, it could be creating a cold draft in rooms in your main floor. The good thing about this draft source is that the floor joists are easy to work on from the basement – so you can add insulation if it’s missing without removing flooring.
If you don’t have a basement but a crawlspace, the floor joists are likely insulated. If they’re not, though, you’ll want to do so as soon as possible. While you’re insulating, you'll want to install a vapor barrier and possibly some kind of sheeting to prevent moisture exposure and nesting rodents.
Your firplace chimney has a damper that is designed to keep the cold air out of your house when there’s no fire. These cast-iron dampers may not seal effectively, however, and may be a bit more conducive to a draft than you'd like. You can install glass doors on your fireplace to act as a further air barrier. Another option is to place foam insulation in the chimney opening when it's not in use. For a little more aesthetically pleasing solution, check out a chimney balloon that actually expands up into the flue to stop warm air from escaping but in a “hidden” manner.
Wherever Materials Meet on Your Home's Exterior
A visual inspection of your exterior will also help you identify any draft-causing areas. An example might be where your home's concrete foundation meets the wood framing of the walls. Other areas to check out include where the siding meets your chimney and on exterior corners. These gaps can not only lead to air loss but also allow water in, which could cause costly moisture damage issues.
Stopping drafts in your home is an ongoing process. Stay vigilant and attentive so that you can enjoy the most energy-efficient property possible.
Footnote: the lead illustration depicts air leaks in a typical home: A) kneewalls (in a finished attic); B) attic hatch; C) wiring holes; D) plumbing vent; E) open soffits; F) recessed lights; G) flue or duct chaseways; H) foundation rim joist (where framing meets founation walls); I) windows and doors.