Tips for Keeping Summertime Electric Bills Down

1. Size it right: Make sure your window air conditioner has the proper cooling power for the space. A good rule of thumb is 20 British thermal units for every square foot of space. A too-large unit will cycle on and off more than it should, and a too-small one will constantly work harder to cool beyond its designed capacity — wasting energy in both cases.

2. Keep cool air in: Make sure your air conditioner isn't working harder than it needs to by sealing any leaks that let cool air escape. Use weatherstripping around window frames and doors and caulk on gaps around vents, pipes and wiring.

3. Clean the air filter: Window units have reusable air filters. Clean air-conditioning unit air filters regularly, as accumulated dust and debris can clog up and restrict airflow, making the system work harder. Find online directions or tutorials for cleaning air filters (examples here and here). It's also a good idea to check the seal around the unit for leaks; if cold air is escaping or warm air is entering, use weather stripping to reseal the space around the unit.

4. Convenient alternative: Portable indoor air-conditioning units are easier to set up and get started than a window unit for a similar retail price and are helpful for spaces where window units can't be installed. While portable traditional units are generally less efficient, portable heat pumps are also available.

5. Mind the hose(s): Portable units can be moved from room to room; however, they need windows or exterior access. The unit's exhaust hose is meant to eject warm air outside; higher-efficiency units have a separate hose for outside air intake. Ensure the unit has a window venting kit (included with purchase or sold separately) that completely seals the gap between the mouth of the hose(s) and the open window space.