Here’s a room-by-room guide to saving money and benefiting the Earth while still enjoying some summertime fun.

By Kimberly Palmer and Maura Judkis of U.S. News & World Report

Throughout the house: “Make sure your house is leak-free,” says Ronnie Kweller, spokeswoman for the Alliance to Save Energy, or else “nice, cold, expensive air is going out the cracks.” You might want to consider assigning this task to a professional. Through the Energy Star online directory, you can find a local auditor who will use diagnostic equipment to test your home for areas where air conditioning might escape. Your auditor will probably do what’s known as a blower door test, which lowers the air pressure in your home and reveals leaks. He or she may also take a photo of your house with a thermographic camera; the red areas of the photo will indicate where better insulation and sealing are needed.

If you don’t want to shell out money for an energy auditor, you can perform a casual energy audit yourself. Efficiency experts recommend feeling around baseboards, windows, doors, light switches and electrical sockets for air leaks. Air can escape or enter anywhere that two different building materials meet. Kweller also recommends walking around your house with incense to see if the smoke blows in when you pass windows. Kweller says old wooden windows are especially prone to this kind of leakage.

If you find problem areas, seal with foam or caulking, which you can find at a hardware store. Insulation that meets certain efficiency criteria is eligible for federal tax credits. Kweller says properly sealing your house can save up to 20% on your utility bill.

Using a programmable thermostat so that the temperature automatically rises when no one is home during the day can yield annual savings of about 30%, Godwin says. While about 25 million households own programmable thermostats, only half of those people take advantage of them.

Replacing older light bulbs with compact fluorescents not only reduces your electricity bill, it can help save energy on air conditioning since fluorescents generate less heat, Kweller says. She estimates that each bulb can save about $50 over its lifetime.

In the living room: There’s nothing wrong with hosting movie nights this summer, but make sure you shut your entertainment center down when the evening’s over. Simply turning off a television set doesn’t put a stop to so-called “vampire power” — the power that devices consume even when they’re not in use. That’s why you should either unplug your electronics or use a Smart Strip, which cuts power when it’s not needed.

If you’re in the market for a new television, check energy-efficiency ratings. The Energy Department bestows its Energy Star rating to sets that use about one-third less energy than regular televisions. In general, LCD televisions use less energy than plasma screens, but both use more than older sets.

Remember to turn the power off or unplug your digital photo frames when you’re not gazing at those illuminated photos. Over a year, leaving one on costs about $9 — not a lot, but when thousands of people are doing the same thing, it adds up.

In the kitchen: Baking a cake or casserole in the summer will force your air conditioner to go into overdrive. Plus, eating hot food will only make you want to turn the thermostat down. But you don’t have to survive on cold pasta salads and gazpacho this summer. Instead of using your oven, consider an outdoor grill or toaster oven for small amounts of food.

If you’re up for a challenge, try baking cookies on your car — yes, your car. Nicole Weston of the “Baking Bites” blog developed a method of baking cookies with the heat that collects inside cars on steamy days. She suggests parking in the sun, using a thermometer to help monitor the temperature, and protecting your dashboard by putting a barrier between it and the baking sheet. (It should be at least 95 degrees outside and the baking takes around 2½ hours.)

In the bathroom: If you don’t want to spend money on a low-flow toilet, you can still make yours more efficient by dropping a soda bottle filled with sand or water into the tank. It will use less water each time it flushes. Ivan Chan of carbonfund.org adds that small steps such as turning the water off while brushing your teeth or shaving can save a substantial amount of water (and money on your water bill) each year. He also recommends installing a water-conserving shower head.

In the bedroom: Stay cool while you sleep with an overhead fan instead of pumping air conditioning throughout the entire house. Shutting the doors and vents of unused rooms can also lighten the load on your air-conditioning unit.

Outside: A way to reduce cooling costs in the longer run is to plant trees or shrubs so that your house is more shaded, especially on the sunnier side, Kweller says. (For a quicker fix, draw the blinds or shades when you’re not home.)