Choosing a Room Air Conditioner
 
DOE Building Technologies Program: Choosing a Room Air Conditioner
EnergyGuide - Room Air Conditioner Information

Rocky Mountain Institute Home Cooling

Calculator for Sizing Your Room Air Conditioner

ACEEE Top-Rated Room Air Conditioners

Two-thirds of all homes in the United States have air conditioners. Air conditioners use about 5% of all the electricity produced in the United States, at a cost to homeowners of over $11 billion. As a result, roughly 100 million tons of carbon dioxide is released into the air each year¡ªan average of about two tons for each home with an air conditioner.

Switching to high-efficiency air conditioners and taking other actions to keep your home cool could reduce this energy use by 20% to 50%. The most efficient air conditioners on the market are up to 70% more efficient than the typical room air conditioners found in U.S. homes today. There are steps you can take to lower your room air conditioner's energy use.

A room air conditioner's efficiency is measured by the energy efficiency ratio (EER). The EER is the ratio of the cooling capacity (in British thermal units [Btu] per hour) to the power input (in watts). The required cooling capacity depends on the size of the room being cooled. The higher the EER rating, the more efficient the air conditioner. Look for units with an EER of 10.0 or above. Check the EnergyGuide label for the unit, and also look for room air conditioners with the E NERGY S TAR? label.

Proper sizing is very important for efficient air conditioning. A bigger unit is not necessarily better because a unit that is too large will not cool an area uniformly. A small unit running for an extended period operates more efficiently and is more effective at dehumidifying than a large unit that cycles on and off too frequently. Based on size alone, an air conditioner generally needs 20 Btu for each square foot of living space. Other important factors to consider when selecting an air conditioner are room height, local climate, shading, and window size. The Energy Savers Web site includes a