With summer vacations behind us and cold weather not expected for a while, September is a great month for investing energy in home-repair and maintenance projects.

Clean the house’s exterior

Take housecleaning literally by washing down the siding. Use a soft rag or a soft-bristle brush and a hose, not a power washer. While you work, look for places where the paint needs a touch up and follow through after the siding dries.

Even if you saved some of the paint used when your house was last recoated, the touched-up spots might not match other areas that may have faded. Blend new with old by feathering out the edges of the fresh paint.

You might need to completely repaint the windowsills, which typically suffer the most rain and snow damage because the moisture collects on horizontal surfaces.

If your siding is mud-splattered, watch during a rainstorm to see whether water is overflowing a gutter or whether the splashes are coming from rain that falls close to the house. (Lucian Perkins/THE WASHINGTON POST)

Stop splashes

While you wash down the house, keep an eye out for areas where mud has splashed onto the bottom few feet of siding. It makes a house look dirty and can lead to having to pay someone to redo the paint more frequently. Also, wood siding can rot if it stays damp for long periods.

If your siding is mud-splattered, watch during a rainstorm to see whether water is overflowing a gutter or whether the splashes are coming from rain that falls close to the house.

If gutters are the culprit and they don’t just need cleaning, call a gutter-installation company and discuss whether you should install deeper gutters or an additional downspout. If the splashes are caused directly by rain droplets, spread pea gravel a couple of inches deep alongside the foundation. The gravel will change the angle at which the droplets bounce, which will keep the siding drier. And the splashes that do occur won’t be as likely to carry mud.

Replace weatherstripping

You probably won’t notice a drafty door until the weather becomes cold. But if you wait until then to replace mangled weatherstripping, your fingers are likely to become numb in the process. So set aside a pleasant September day to do the job.

Felt or foam weatherstripping is inexpensive and easy to apply, but it doesn’t last long. You’re better off going with vinyl, silicone or metal. The U.S. Department of Energy has an online chart that compares the options.

Tune up your heating system

Don’t wait until you need to turn up the heat to schedule routine maintenance. The good pros will all be too busy then. Now’s the time to arrange for a yearly tuneup of an oil or gas furnace. If you burn wood, schedule a chimney cleaning. If you have electric baseboard or wall heaters, vacuum out any lint and wipe down the grills.

De-clutter the basement

No one wants to spend a glorious fall day holed up underground, especially if the task there is cleaning up a mess. But you can take advantage of the shortening days by devoting some after-dinner time to cleaning out the basement. First, tackle the empty cardboard boxes that tend to pile up. Set aside a few to use while you’re sorting; flatten the rest and set them out for recycling.

Then cull items you no longer want or need. If you haven’t used something in a year, it might be time to part with it. Once you see how much stuff you no longer want, decide whether to give it away or sell it at a garage sale. A beautiful September day is a great time for that.

Get inspired

There are plenty of reasons not to spend every September weekend working on the house. One of them is the Capital Home Show, from Sept. 21 to 23 at the Dulles Expo Center in Chantilly. For a $10 ticket, or $7 if you buy online, you’ll get remodeling tips, cooking demonstrations, an extreme pumpkin carving demonstration and free, one-on-one consultations with designers. Call 703-378-0910 for information.