Seal gaps larger than ⅛ inch around windows and doors to cut your winter heating bill by up to 15 percent. On windows, press adhesive-backed closed-cell foam onto the bottom of the sash. Secure a loose sash by applying a strip of plastic V-channel weather­stripping in the groove the sash slides in, securing it with finish nails. Use foam strips on the sides and tops of doors, and install a door sweep on the bottom.

When gutters aren’t pitched at the right angle, they overflow—and can threaten your once dry . Properly pitched gutters slope between 1/16 inch and ⅛ inch per foot, directing water to the leader and out the downspout. Check the pitch by holding a level even with the gutter; on longer runs, pour in water from a hose and check the flow’s direction. Get instructions for keeping your gutters in good working order.

Cracks in your driveway, walkway, or steps are a big-time trip hazard, and they’ll only get worse if water seeps in and freezes. Luckily, if you can caulk, you can fix concrete—just make sure it’s clean and dry to start. For cracks less than a half-inch wide, squeeze a bead of acrylic latex concrete repair compound deep into the crack, smoothing excess with a putty knife. For larger cracks, trowel on a vinyl concrete patching compound, and let it cure one day before walking on it, three days before driving over it.

If you have ceiling fans, change their rotation to clockwise to push warm air down (usually accomplished by flicking a switch on the base), and while you’re at it, wipe down the blades with a microfiber cloth that traps dust. At month’s end or when the temps drop, remove window AC units. Vacuum the coils and filters, and store them in a cool, dry place, preferably covered to keep out dust and bugs.

During the brightest part of the day or a steady rain, look for streams of light or water entering the attic through the roof or sheathing, which can lead to more serious damage (and critter invasions) if left unfixed. (Another sign of holes is black staining on insulation.) From inside, fill sheathing gaps with closed-cell polyurethane foam. Fix small roof leaks by caulking with tripolymer elastomeric sealant, which is compatible with asphalt shingles and resists UV rays. But don’t caulk large leaks, which tend to develop around chimneys or vent stacks. For now, place a bucket underneath to catch drips and stuff an old towel in the crevices to absorb moisture. Then do a more serious repair before the first winter storm hits.

How do you know if your attic is properly protected? It’s simple: If you can see the tops of the joists, you’ve got a problem. If the existing insulation is roughly even with the tops of the joists, add a new layer of unfaced batt insulation perpendicular to the old one, pushing the pieces together so they fit snugly side by side. On the other hand, if the existing layers are more than an inch above (or below) the joists, blown-in cellulose or fiberglass does a better job of filling the crevices. To find out how much you need, depending on where you live, type your ZIP code into the ZIP-Code Insulation Program at the Oak Ridge National Laboratory. And give yourself a pat on the back for keeping up with fall upkeep.