Sizing is important for room air-conditioning units. In fact, a room air conditioner that's too big for the area it is supposed to cool will perform less efficiently and less effectively than a smaller, properly sized unit.
If your air conditioner is old, consider purchasing a new, energy efficient model. ENERGY STAR qualified room air conditioners use at least 10 percent less energy than conventional models.
Look for the ENERGY STAR and EnergyGuide labels.
Buy a qualified ENERGY STAR Room Air Conditioner and get $15 off your purchase from your participating municipal utility through a mail-in rebate.
Provide shade around your air conditioner, and it could reduce your cooling costs by nearly 3 percent.