A true eco champ would suffer through this summer's sweltering heat in the name of conserving energy. But let's face it, most of us just don't want to suffer the sweat. If you need to cool down, but can't stand to contribute to the earth heating up, consider purchasing a newer, energy efficient unit.

If the past few years are any indication, this summer isn't likely to be a cool one. 2007 tied with 1998 as Earth's second-warmest year in a century, according to NASA, which ranks 2005 as number one. And the eight warmest years have all occurred in the past decade. April's a good time to shop, as it's still before summer's first heat wave, which seems to come earlier each year and causes a run on the air conditioner dealers. By June there are fewer choices—and prices surge.

That said, if you care about the Earth and your budget, you're right to be cautious about air conditioning, which is responsible for 22 percent of the electricity consumed in the average U.S. household, according to the Rocky Mountain Institute. Our electricity still mostly comes from coal-burning power plants, and, lest anyone these days needs to be reminded, "the atmospheric buildup of CO2 and other greenhouse gases is largely the result of human activities, such as the burning of fossil fuels," according to the EPA.

Here's what to do.

Choose Energy-Star-rated models. Air conditioners bearing the EPA's Energy Star label have to be at least 10% more efficient than conventional ones. There’s been a vast improvement in the past ten years, so it’s a good time to replace an older model, according to the American Council for an Energy Efficient Economy, www.aceee.org. For a list of models, go to www.energystar.gov and click on Room ACs in the left-hand toolbar.

Consumer Reports recommends these Energy Star-rated models: Friedrich SS10L10-A ($700, EER: 12; 800-541-6645); GE AGM06LH ($180, EER: 10.7) and AGM08LH ($240, EER: 10.8; 800-626-2005); Frigidaire FAA067P7 ($150, EER: 10.7) and FAA087P7 ($180, EER: 10.8; 800-374-4432).

Turn off the AC when you go out or the weather's cool, and keep your thermostat at 72 degrees or higher in warm weather. For every degree you turn it up, you’ll save 121 pounds of carbon emissions a year as well as reduce your electricity bill.

It’s tax time, and many states and utilities give tax credits of up to $75 for Energy Star rated air conditioners, and $1-3 for CLFs (hang onto those original sales receipts!) Check out what’s available in your state. Some states and utilities offer rebates for trade-ins of older units.

More energy-saving tips:

To ease the burden on your AC and electricity bill, close your blinds or curtains during peak sunlight/heat hours

On a cold night or day with clean air, turn off AC and open your windows. Circulate fresh air into your house using fans.

Choose energy-efficient compact fluorescent lightbulbs (CFLs) and appliances (see list on Energy Star website) to reduce the amount of indoor waste heat produced by these devices.

Seal and caulk walls and windows to prevent cold-air leaks.

Relax! That also burns fewer calories (and generates less heat).

Now you can chill out without the guilt.

This article originally appeared in Plenty in March 2008. The story was added to MNN.com.

Copyright Environ Press 2008

Cool down: Energy efficient AC
When it comes to air conditioning, cool it. Adopting greener habits can lighten the impact on your wallet, and on the planet.