For window air conditioners adjust the thermostat control upward to reduce cooling costs. For each degree the cooling setting is raised a savings of about 9 percent is achieved, up to about an 80 degree setting. Above 80 degrees the savings percentage is smaller.

For window units with heating by electric elements or by a heat pump adjust the thermostat heating control downward to reduce heating costs. For each degree the heating setting is lowered a savings of about 3 percent is reached, down to a setting of 70 degrees. Below 70 degrees the savings percentage is smaller.

Inspect, clean or replace the filter located in the front grill every month on window units. For air conditioning a dirty filter can cause a 10 percent reduction in air flow and that can increase the operating cost by up to 11 percent.

The inside evaporator coil on window units should be keep clean and the outside condenser coils should be clean and free of leaves and other objects that can be sucked in.

On window or room air conditioning units make sure there are no leaks around the window and the unit is securely mounted. Caulk or seal any place air could leak out or water might enter at the mounting window.

For window units the available EER rating will vary depending on the cooling capacity size and the voltage. For most 115 volt models the EER range is from around a high EER of 11.0 down to a low EER of 9.5. Units in the cooling capacity size range of 10,000 to 13,000 Btuhs have a EERs as high as 12.0, with models down to a low EER 9.5 and in between. For 230 volts units the EER will range from a high of 11.5 to a low of 8.5, again depending on the cooling size. For window units, typically the higher the EER the more the model costs. Our recommendation is to buy the highest EER model as practical