The summer heat wave that's baking the eastern U.S. is keeping air conditioners running non-stop, running up huge electric bills that will come due next month.

The Alliance to Save Energy, a Washington, DC-based conservation group, has projected that the average U.S. household will spend more than $2,000 on home energy this year, so cutting monthly bills by 10 or 20 percent with energy efficiency means significant savings.

The group also notes that certain energy efficiency home improvements qualify for generous federal income tax credits of up to $1,500. The credits expire on December 31, 2010, so it may be a good time to consider taking advantage of them.

The Alliance suggests the following tips to help reduce the cost of beating the heat:

1. Cooling puts the greatest stress on summer energy bills, so make sure your AC equipment is in top running order. A professional "tune-up" could save you the cost and misery of a breakdown on the hottest days.

2. Replacing your 12+ year old central air conditioning system (CAC) with an ENERGY STAR qualified model could cut your cooling costs by 30 percent, according to the Environmental Protection Agency (EPA). And while these products can have a higher purchase price, the cost difference will be paid back over time through lower energy bills, EPA says.

Size matters

3. For optimum performance, make sure CAC systems or window units are properly sized. EPA says a system that's too large will not keep your home comfortable due to frequent "on/off" cycling. Incorrect sizing can also put stress on system components and shorten the equipment's life. A qualified contractor can help you ensure proper sizing.

4. Purchase the AC unit with the highest Seasonal Energy Efficiency Ratio (SEER) that you can afford -- the higher the SEER level, the more energy efficient the equipment. Current federal appliance standards require a SEER rating of at least 13 on CAC systems.

5. Clean or replace CAC system filters monthly -- and window unit filters even more frequently.

Be a fan of fans

6. Using ceiling fans to circulate air will make you feel cooler and possibly allow you to raise the temperature setting on your AC thermostat by a few degrees. But be sure to turn the fan off when you leave the room, because fans cool people, not rooms.

7. A programmable thermostat automatically coordinates indoor temperatures with your daily and weekend patterns, reducing cooling bills by up to 10 percent by raising the indoor temperature while the house is empty -- yet ensuring that when you return home, it's cool and comfortable.

8. Plug energy leaks with weather stripping and caulking and be sure your house is properly insulated to save up to 20 percent on cooling (and winter heating) bills. These and other energy efficiency home improvements can generate a federal tax credit of up to $1,500; Check online for details on qualifying products.

9. Your air conditioner works overtime to cool hot air from sunny windows, so consider investing in energy-efficient windows to save money and increase indoor comfort. Efficient windows, glass doors and skylights are eligible for federal tax credits. If you live in the Sun Belt, look into "low-e" windows, which can cut the cooling load by 10 to 15 percent, according to the U.S. Department of Energy's Energy Savers booklet.

10. Curtains and shades on the sunny sides of your home will provide additional relief.