What to Look For

If your current air conditioner is more than eight years old, it's time for a new one. Over the life of the product, the amount you'll save in energy bills will more than likely exceed the cost of the new unit.

The following are basic criteria to use when choosing a new system:

BTUs

The cooling capacity of an air conditioner is measured in British thermal units per hour (Btu/hr). To find the best BTUs needed to cool your room, multiply the square footage of the space by 10 and then add 4,000.

Energy Star Rating

The Environmental Protection Agency's "Energy Star" ratings indicate that an appliance is at least 10 percent more energy-efficient than the minimum federal standards.

EER

A room air conditioner's EER, or Energy-Efficiency Ratio, is the ratio of the cooling output divided by the unit's power consumption. The higher the EER, the more efficient the model.

Anti-Microbial Filter?

Most room air conditioners come with reusable electrostatic filters, which may be treated with triclosan. If purchasing a unit with an antimicrobial filter, ask the retailer to replace it with an untreated electrostatic filter.

Shopping Tips

• Check if your state energy office or local utility offer rebates and trade-ins of older models to encourage the purchase of energy-efficient units. You could end up saving $75 or more on your purchase.

• If you live in a very humid climate, look for models that are good at removing moisture; ask about the rate of water removal (in pints per hour).

• At the store, compare the energy consumption and usage costs of one model to another using the yellow "EnergyGuide" label on the product

Usage Tips

• If your unit has a thermostat, set it to 78 degrees F.

• At night, use your air conditioner's fan-only mode

• Use the recirculate option instead of constantly cooling hot air from outdoors.

• Turn the air conditioner off when you're out.

• Clean the filter often (biweekly or as needed), and where possible, hose down the back of the unit to remove debris that can clog cooling coils.

• Make sure window models are installed as tightly as possible to prevent hot air from seeping in around the unit's edges.