Look around your home. Like most of us, you’ve probably got lights blazing, an air conditioner humming, and everything from your cell phone to a coffeemaker plugged in and ready to go.

The convenience of our wired homes, however, comes with a price. U.S. households spend on average $1,000 a year on electricity, accounting for about half of all energy costs.

And it’s costing our planet, too. The majority of the electricity we use is produced at coal-burning plants, which release tons of carbon dioxide emissions into the earth’s atmosphere, trapping the sun’s heat and contributing to global warming.

The good news: If every household in the United States were to cut its energy consumption by 15 percent, about 200 coal-powered plants could be retired. In addition, you would pocket $150 to $250 a year.

Kitchen appliances account for more than a quarter of the electricity consumed by U.S. households.

Refrigerators are the biggest offenders. They and freezers should be equipped with thermometers, keeping the refrigerator at 36 to 40 degrees Fahrenheit, and the freezer at zero to five degrees Fahrenheit. Any colder, and you are using more energy than necessary.

Check that the seal on each door is tight by closing it on a dollar bill. If you can slide it out easily, replace the seal.

If you’ve had your fridge for more than a decade, consider buying a new Energy Star model. That upgrade can save you $75 to $100 per year on electricity. (Energy Star is run by the Environmental Protection Agency in connection with the U.S. Department of Energy; it recognizes consumer goods that meet its standards for efficiency. It also rates home electronics, heating and cooling equipment, office equipment and lighting. Look for its logo when you’re in the market for other items, such as a new television, air conditioner, computer monitor or lamp.)

When cooking, use a toaster oven or microwave for single dishes and reheating instead of a full-size oven.

Run your dishwasher only when it’s full. Turn its heat-dry function off and you’ll save even more.

Run your washer and dryer only when you have a full load of laundry. If you have to wash a small amount, use the small-capacity setting, which cuts water use by as much as 50 percent.

Any appliance with a clock, a light or a remote uses energy continuously, as does any sort of charger when plugged in. These phantom power losses account for 5 percent to 15 percent of your electricity usage.

If you need a clock in the kitchen, hang one on the wall and unplug your coffeemaker, microwave and other countertop appliances between uses.

For rechargeable items, set up a station to plug all cell phones, MP3 players and personal digital assistants into one power strip. Charge them when you get home and turn off the strip when you go to bed.

Plug your TV and other home-entertainment equipment into one strip and flick off all the electronics at once. If you have a cable box or a digital video recorder, choose strips that let you keep some of the outlets electrified even when others are turned off, so you don’t miss your shows. (It’s a popular misconception that you’ll damage your electronics by turning them on and off frequently.)

To keep your electricity bill from spiking dramatically when the weather’s warm, use less air-conditioning whenever possible. Stay cool with fans instead, and turn them off when you’re not in the room.

If nights are cooler where you live, keep windows open as you sleep, and then close them and pull down the blinds in the morning to keep the cool air inside.

Have your air conditioner serviced regularly so that it runs efficiently. Lighting may account for 5 percent to 10 percent of your annual home-energy expenditure.

When working, use a desk lamp instead of overhead lights, especially if you’re in a large room.

For other tasks, try to work by a window during the day so you can turn off overhead lights.

Reduce lighting expenses by replacing incandescent bulbs with compact fluorescent lightbulbs (CFLs). They cost more but last up to 13 times longer and use just 25 percent of the electricity. You’ll save more if you replace the bulbs you use the most, such as garage and outdoor lights.

Questions should be addressed to Ask Martha, care of Letters Department, Martha Stewart Living, 11 W. 42nd St., New York, NY 10036. E-mail to mslletters@marthastewart.com.

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