Common Room Air Conditioner Terms You'll Need to Know

Choosing the right room AC for your living space is easy when you know what to look for.  Before you go shopping, make sure you understand what these 3 important terms mean:

BTU: This is an acronym for "British Thermal Units" and a unit of energy used in the power and heating and cooling industries. In terms of air conditioners, this describes a unit's power and cooling capacity. The higher the BTU rating, the stronger the air conditioner.  Matching Btu requirements to room size is important. The room won't cool efficiently if the BTU rating is too low or too high for the size of the room.

EER: This stands for "Energy Efficiency Ratio."  This measures how energy efficient an air conditioner is at a specific level (usually 95° F), and can be calculated as a ratio of BTUs to the power input in watts.  The higher the EER, the more energy efficient the room air conditioner. 

Auto-Evaporative: A type of technology utilized by many portable room air conditioners involves evaporating condensed water and exhausting it through a main venting hose and through a window, drop ceiling, or wall. A room AC with auto-evaporative technology does not need to be frequently emptied (unless used in an extremely humid climate).

For more information on room air conditioners, take a look at our air conditioner buying guide.