Not ready for a new fridge? Make your old one more efficient.

RODALE NEWS, EMMAUS, PA—Refrigerators are notorious energy hogs: Some can add up to $250 to $300 a year to your household electricity bill. But it doesn’t have to be that way. “Ideally, running your fridge should only cost about $70 a year,” says Pascale Maslin, founder of Energy Efficiency Experts, a Washington, DC–based energy audit firm. Using less energy to keep your cold stuff cold also translates to fewer emissions of greenhouse gases and pollutants.

Upgrading to a newer, more efficient refrigerator is one way to save: Units on the market today are 70 percent more efficient, on average, than those sold 10 years ago, she says. But if you're not looking to buy at the moment, an older fridge can be made significantly more energy efficient—saving you money and reducing associated fossil fuel emissions—with a few simple steps:

• Clean the condenser coils. Brushing or vacuuming off the accumulated dust and animal hair can improve a refrigerator’s efficiency by as much as 30 percent. Those coils let heat escape from the fridge, so you don't want anything blocking them. It's worth the effort to pull the appliance back from the wall now and then for cleaning. And here's good news: Most models built in the last decade place coils underneath instead of in back, so they’re easy to reach by pulling or unscrewing the grille off the lower front. Just unplug the fridge and gently brush or vacuum anything that's collected on the coils.

• Stock your shelves. Believe it or not, an empty fridge is a less efficient refrigerator than an almost-full one. Solid objects inside a fridge retain their coolness better than air (that spills out when you open the door), so keep your fridge packed so it doesn’t have to work as hard to restore its set temperature. If you don’t have much food to chill, put empty milk jugs on the shelves to fill space. Aim to keep both fridge and freezer filled to 60 to 80 percent of their capacity. Packing them fuller than that reduces efficiency by preventing air from circulating, so food chills unevenly.

•  Clean around the door. The insulating gasket—the rubber strip that keeps the door sealed when it's closed—won’t seal properly if it's caked with grime. That lets cold air escape. To check the seal, close the fridge door on a dollar bill: If you can pull it out, your door may not be airtight. Try wiping away the glop with some warm water or a gentle natural cleaner.

• Set the right temperature. Keeping food colder than necessary wastes energy. Government-recommended temperatures are 37 to 40 degrees for fridges and 5 degrees for freezers. Buy a fridge thermometer so you can tell what settings keep your icebox in the cold comfort zone.