1. Inspect the AC, part 1.
For about $75 to $200, a technician will tune up your cooling system to manufacturer-rated efficiency — and you won’t sweat the first hot weekend with an out-of-commission air conditioner. Call your electric utility to see whether it offers incentives. Contractors may offer discounts early in the season for inspections or for annual maintenance contracts.

Look for a heating and air-conditioning contractor that belongs to the Air Conditioning Contractors of America, employs technicians certified by the North American Technician Excellence (NATE) program, and follows the protocol for the ACCA’s “national standard for residential maintenance” (or the “QM,” short for quality maintenance).
Note: Dirty filters make air conditioning work harder, increasing energy costs and possibly damaging your equipment. Contractors will put in new filters during a tune-up, but you should check monthly to see if they need replacing.

2. Inspect the AC, part 2.
Air conditioners draw moisture from interior air, called condensate, which must run off outside. If sediment and algae clog the drains, water may back up, making your home more humid or creating water damage. Technicians will check the drains during a tune-up; if they clean them out, it could cost up to $100. If you live in a humid climate, you may want to check and clean them yourself periodically.

3. Put the temperature on autopilot.
Energy Star says that for an initial investment of $50 to $150 for a programmable thermostat, you can save about $180 annually on cooling and heating bills — if you can live with higher indoor temperatures in summer (and cooler temperatures in winter). In the summer, that means setting your thermostat 7 degrees higher than usual when you’re away from home and 4 degrees higher when you’re asleep (the preprogrammed settings are 78 degrees when you’re at home and awake, 85 degrees when you’re away from home, and 82 degrees when you’re asleep). Set the hold or vacation feature for a constant, efficient temperature when you’re away for the weekend or on vacation.
In summer, you can make those settings more tolerable if you install ceiling fans (you may even be able to switch off the AC more often). Ceiling fans create a slight “wind chill” effect, making you feel cooler. Just remember that a ceiling fan cools people, not a room, so turn it off when you leave the room.

4. Caulk the cracks.
If the gap around a door or window is wider than a nickel, you need to reapply exterior caulk. Check window-glazing putty, too, which seals glass into the window frame. Add weatherstripping around doors, making sure that you can’t see any daylight from inside your home. You’ll save money on air conditioning and avoid having to repeat this task this fall.

5. Clean out the gutters.
Nature’s detritus– decomposed leaves, twigs, and spring petals and seeds — may be worse in spring than in fall. Add extensions to downspouts to carry water at least 3 to 4 feet away from your home’s foundation. You can use 4-inch corrugated plastic pipe.

6. Repair your roof.
An easy way to inspect the roof to find damaged, loose or missing shingles without risking life and limb is to use a pair of binoculars. If the damaged section is more extensive, you’ll need to get a contractor. Check and repair breaks in the flashing seals around vent stacks and chimneys, too. If your home has a flat roof with a parapet (a short wall around the perimeter), check the flashing that seals the joint between them. Heavy snow can split the flashing, resulting in leaks.

7. Keep your basement dry.
If you have a sump pump, make sure it’s operating properly . If water seeps through the foundation walls (does your basement smell musty? are the walls stained?), the best solution is probably to excavate the exterior wall and apply sealant . If groundwater pushes up and into the basement, an interior perimeter drain and sump pump may be called for.

8. Deal with your deck.
Resealing is always a good idea to protect the wood. But more important, before you invite the clan for a reunion, make sure your deck can handle the load. The North American Deck and Railing Association says that deck components inevitably age, but that salt air can hasten deterioration and heavy snow can cause stress damage. At a minimum, test several areas of the deck, especially those that tend to stay damp, for decay. Two signs: The wood is soft and spongy, and if you poke it with an ice pick or screwdriver, it doesn’t splinter.
Check that nails and screws are well-seated and not corroded. (The ledger board that connects the deck to the house should be fastened with screws, not nails.) The deck and stairs shouldn’t sag or sway when you’re walking on them. Railings and banisters shouldn’t give when you push on them.

9. Call a chimney sweep.
Look for chimney sweeps certified by the Chimney Safety Institute of America. The sweep will make sure that the chimney cap is in place and the damper is working properly. With a wood-burning fireplace, you can close the damper whenever the fireplace is not in use. In summer you’ll save energy and reduce unpleasant odors carried by the inflow of air and aggravated by humidity.
For the greatest energy savings, insert a fireplace “draft stopper” in the flue, preferably after you’ve had the chimney cleaned. (Look for one made by Battic Door Energy Conservation Products; $55 on Amazon.com.) For a really cheap alternative, you can make one out of an old foam-rubber seat cushion or a pillow placed in a heavy plastic bag. Stuff the cushion into the flue and tie a long tail to it, so you don’t forget about it the next time you make a fire.

10. Don’t overwater.
If you have an irrigation system, you may be overwatering (and wasting money on water bills) because a controller isn’t properly set for your yard’s needs or because of broken or leaky components.

11. Lose the lint.
Even if you clean your clothes dryer’s lint trap before every use, the vent accumulates lint over time, like plaque in your arteries. That’s especially likely if snow covered the exterior backdraft damper for a while last winter. Also, the longer the connection between the dryer and your home’s exterior, the bigger the build-up is likely to be. A clogged vent can reduce your dryer’s efficiency and create a fire hazard.