Snow in Denver. Falling leaves in New England. Oil topping $90 a barrel. Yep, winter's coming, and for many of us it's accompanied by the annual knot of concern over high home heating costs. Global uncertainties and the falling dollar have driven energy prices to new highs in recent days, and given the National Oceanic and Atmospheric Administration's prediction that this winter will be 4% colder than last year's, heating costs are at the forefront of many people's minds.

Fortunately, nearly any home in cold-weather territory can benefit from some thoughtful preparation for winter. Specifically, unless you've got a brand-spanking-new house with special "green" features, such as extra-thick double-insulated walls and triple-paned windows, odds are you'll be losing heat when the cold weather sets in. And while you're unlikely to make an older home as energy-efficient as new "green" construction, there are simple steps you can take to greatly improve your winter comfort -- and lower your energy costs.

Sealing the envelope
Home-insulation experts and architects often use the term "envelope" when talking about a building's level of insulation. It's a useful mental model; clearly, the better-sealed the envelope, the less likely it is that its contents -- warm air -- will leak out.

Improving your home's envelope doesn't have to mean retrofitting expensive blown-in cellulose insulation or multipane windows, though those steps certainly yield significant benefits. There are some simple, temporary, do-it-yourself things you can do that will make a big difference. Here's a plan of attack:

  • Find the leaks. Does your house have an exhaust fan? If so, on the next cold and blustery day, close all the doors and windows and turn the fan on. Then snoop around the edges of your windows and doors. If you have trouble feeling the air moving with your hand, dangle a short length of thread or a burning incense stick near the cracks instead. If you detect airflow, you've got a leak, and you're losing heat. Note all of the leaks -- on paper, or with chalk marks on the window and door frames -- and move to the next step.

  • Replace weatherstripping or apply caulk. The "proper" solution here is to replace worn or ineffective weatherstripping. It's not a hard job -- weatherstripping comes in two basic varieties, tubular and angled, and is generally installed with small nails or with glue. (If in doubt about the correct variety for your window or door, ask at the hardware store.) Alternatively, for a quicker temporary fix on a window, apply caulk or sealing foam around the cracks. General Electric (NYSE:GE), believe it or not, makes an excellent line of silicone household caulks that I've used with success for years. Your local Lowe's (NYSE:LOW) or Home Depot (NYSE:HD) will have several varieties of caulks and sealing foam; ask for help if you're not sure. This can be done in a few minutes and is quite effective, but you'll have to peel or scrape it all off in order to open the window in the spring.

  • Alternatively, apply plastic film. An even quicker solution is to apply plastic film -- a sort of heavy-duty Saran Wrap that is attached to the window's frame and then blown with a hair dryer until it shrinks and becomes smooth. You can buy the film in kits with double-sided tape and instructions -- 3M (NYSE:MMM) makes a great one that is widely available -- and it's very easy to install. It's not the prettiest solution, but it's not awful and it works really well -- consider using it in less-often-used rooms, or in bedrooms. Some sources warn that the double-sided tape can lift the paint on your window frames, but we've used the 3M kits for years and never had a problem. We did, however, find that our cat liked to shred the plastic, so we now save the plastic film for windows she can't easily reach. If you have a cat, caveat.

Note that there's generally no need to worry about sealing up a home too tightly. While it's true that some air circulation is required to maintain good indoor air quality, it's practically impossible to seal up an older home so much that that becomes a problem. If you're concerned about it, though, consult a contractor who does home EnergyStar ratings -- fresh air flow can be tested and assessed, and an energy-efficient ventilation system installed if there's a problem.

In Part 2, we'll look at other simple steps you can take to improve your home's efficiency before winter sets in.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.