Free for all
Saving energy begins with good habits in the house, and a drop in temperature is your cue that it's time to "winterize" your routines. For starters, get the most out of solar energy in its rawest form by opening the curtains and shades on windows that receive direct sunlight. Leave them open so the rays can warm the room, then close them again at night to provide an additional barrier against the cold.

Use ventilation fans sparingly. Fans in the kitchen or bathroom that vent to the outdoors are great for removing odors and humidity, but they also remove heat: Left on, they can draw all the heat from your home in about an hour. Ceiling fans, on the other hand, can help keep you warm. Since heat rises, a room is usually warmest near the ceiling. Circulate that trapped air in winter by reversing the direction of the blades (there's usually a small selector on the fan housing), and keep the fan on its lowest setting.

If you use a fireplace, be sure to close the damper on the flue once the firebox is smokeless and cool. Otherwise, warm air rushes up and out, which can create a wicked draft. Don't forget to knock your thermostat setting way down while you're enjoying the fire. And be sure to abide by burn bans and other air-quality measures in your area: Emissions from fireplaces can be significant contributors to wintertime air pollution.

There's no sense heating your home to room temperature when you're away or tucked comfortably under the covers, so always be sure to reset your thermostat appropriately. The Environmental Protection Agency recommends dropping the temperature by at least eight degrees when you're sleeping or out of the house. As a rule of thumb, lowering a thermostat by 10 to 15 degrees for eight hours a day can save over 10 percent per year in home heating costs, which equates to more than a month of free heating.

Nickels and dimes
Managing that thermostat is a No. 1 priority for saving energy and reducing your carbon footprint. If you're still using a manually adjusted model, consider upgrading to a programmable thermostat. They start at around $25, and you'll certainly see that money come back in energy savings. With a little research to select the right type, and some trial and error once it's installed, you can conserve money and energy without sacrificing comfort.

Locating and sealing air leaks in your home requires only a small investment of time and money. The sealants typically used -- caulk, weather stripping, vinyl strips, adhesive foam -- are inexpensive and available at every hardware store. The only tricky part is figuring out where exactly your house is losing heat. Doors and windows are common culprits. One effective method for locating the precise location is to light a stick of incense, trace it around the frame, and then follow the smoke: Wherever the smoke blows into the room or is drawn outside, you have unwanted airflow.

Big leaks around a door can usually be sealed with weather stripping and/or a door sweep (a plastic or rubber skirt that attaches easily to the door bottom). Around windows, polyurethane caulk is great for sealing gaps around the frame. If you want to caulk inside seams, consider using removable caulk since it pulls right up in the springtime. When windows won't close snugly, a strip of adhesive foam can fill the space where the bottom of the window meets the sill. Adhesive foam is also useful on the inside edge of a trap door to the attic, which is an easy route for escaping heat.Less commonly addressed leaks include those around electrical outlets, gaps where outdoor water lines enter the foundation, small spaces around cable and phone lines, and dryer vents. None are especially difficult to seal, but if you don't have a knack for do-it-yourself repair, ask a friend or contact a reputable handyman. The small investment will pay for itself, and then some, in the months to come.

Invest and save
Small leaks can certainly add up to unnecessary energy expenses, sending your money out the window like so much warm air. To reduce the risk of bigger problems, you'll need to bite the bullet on expenses such as annual maintenance on your heating system.

If your home still won't stay warm, consider having a qualified contractor conduct an energy audit to determine where you're losing heat and money. The price of adding insulation, upgrading a heating system, or replacing windows may initially send a chill down your spine, but the energy savings are usually worth it in the long term (your local power company might even have an incentive offer for the upgrades you're considering). The first day you find yourself cozy and comfortable while the wind whips and the snow stacks up outside, you will know you've made a wise choice.