You can fill gaps between a window frame and a house frame with Great Stuff Window & Door Insulating Foam Sealant. Weatherstripping, right, will also protect your home — and your pocketbook — once winter arrives.

AP / Great Stuff

Winter brings cleansing rains, billowing snow, crystal clear star-filled evening skies — and energy bills that can choke a horse.

So, as beautiful as the season might be, it’s a good idea to spend the rest of the summer and fall getting ready for it.

Heating: Changing your furnace filter isn’t difficult or expensive, and it makes good sense. However, there are furnace service and maintenance issues that, if left unchecked, can prove far more costly. Yes, change the filter, but be aware that the biggest single energy culprit in a central heating system could be something as simple as a duct leak. Leaky ducting can spew hundreds of dollars worth of heat (or air conditioning) into your attic or crawl space. Is your basement overheating? It could be a leaking duct. You can hire a heating contractor to test your system, but first search out leaks yourself. If ducting is insulated, and it should be, then pull back the insulation at locations that appear to be junctions, or where ducting is bent or dented. Once you have done all you can to ensure that you have no leaks, have a heating contractor come in and perform a pressure test.

Insulating heat ducts: Duct insulation is actually a pretty recent code requirement. You may well have ducting that is well sealed, but if it isn’t properly insulated, you will pay more for your heating than does your neighbor who has taken the time to insulate. One-inch-thick duct insulation is sold in 1-foot-wide rolls, and is easy to install. All you need to do is wrap and overlap: While wrapping the insulation around your ducting, just make sure it overlaps an inch or two. When you get to the end, lace a nail through the last overlap to hold the insulation in place. Any medium-size nail will work. While insulating duct work in itself is easy, a lack of working space — say, a crowded attic or crawl space — can make the chore difficult. Still, it beats struggling to pay your utility bill.

Pruning trees: A deciduous tree is the most energy-efficient type. In the winter, it loses its leaves and lets the sun’s warmth help heat your home. During the summer, its leaves shade and cool your home. All you have to do to ensure years of protection is keep your trees fed, watered and pruned. Feeding and watering is pretty easy, but pruning can be a back breaker and, if improperly performed, can damage or even kill a tree. Pruning in the winter is a no-no. Pruning creates open wounds. Don’t expose your tree to frost damage by cutting and hacking when chilly weather is expected. Also, pruning cuts should be made at a 90-degree angle to the branch. Cutting at other than 90 degrees exposes more of the “wound” than necessary. No, it doesn’t matter which pruning tool you use as long as cuts are clean and square. Yes, a ladder is needed, and a safety rope is even more important.

Leaks of all kinds: Home maintenance Web sites abound with tips on sealing and caulking, the use of expandable foam, and how to check and replace weather stripping at doors and windows. Unfortunately, the list of items is so long that most of us don’t take the time to get half of it done. Also, some people think caulking and sealing lasts for years (“Hey, the caulking is guaranteed for 50 years!”). Not! The caulking may be guaranteed, but your home isn’t. Homes shift as the ground expands and contracts from changes in moisture season to season. So, here’s the list one more time, and just for this season:

•Caulk all exterior doors and windows where the exterior siding meets the trim and where the trim meets the window frame.

•Caulk all joints and gaps in exterior siding and trim, and where the siding meets the foundation.

•Weather strip all windows and doors. For windows, be sure to remove the moving section first, so that the weather stripping is fully accessible. For doors, be sure to check the bottom. Hold a flashlight at the bottom of the door at night. If you can see the light from the inside, the weather stripping needs adjustment or replacement.

•Seal plug and switch covers at all walls, both exterior and interior. For about 25 cents a piece, you can radically reduce air infiltration.

•If you have an older home, remove interior door and window trim and fill the gap between the window or door frame and the house frame with expanding foam sealant. Caulking alone on the outside will not do the trick.

•Use expanding foam sealant to fill penetrations in:

1. Exterior siding

2. The crawlspace

3. The basement

4. The attic

5. Inside kitchen and bath cabinets

Sealing the outside of your home will not only reduce energy costs, it will protect the siding and trim from water damage.