Low price and high efficiency make room air conditioners an inexpensive alternative to central air for cooling one or two rooms. By choosing an energy star qualified air conditioner, it would prevent 1.2 billion pounds of greenhouse gas emissions, the equivalent emissions from 100,000 cars. Energy star qualified room air conditioners often include timers for better temperature control, allowing you to use the minimum amount of energy you need to cool the room.

Many people buy an air conditioner that is too large thinking it will provide better cooling. However, an oversized air conditioner is actually less effective and wastes energy. A properly sized unit will remove humidity effectively as it cools.

Using the square footage and the chart below, determine the correct cooling capacity. Cooling capacity is measured in British thermal units (BTUs) per hour.

Make any adjustments for the following circumstances:

• If the room is heavily shaded, reduce capacity by 10 percent.
• If the room is very sunny, increase capacity by 10 percent.
• If more than two people regularly occupy the room, add 600 BTUs for each additional person.
• If the unit is used in a kitchen, increase capacity by 4,000 BTUs.