Air Conditioner Buying Tips
The ability of an air conditioner to cool an area is measured in BTU/hour. The higher the BTU, the more cooling power the unit has. Don't make the mistake of choosing a model with too much cooling capacity; it will cycle on and off too often, not staying on long enough to remove humidity from the air. Have a rough estimate of the sizes of the rooms you want to cool (in square feet) before you start shopping.
Look for high efficiency air conditioners. Efficiency is measured by the EER (energy efficiency rating), which is displayed on all air conditioners sold in the US. The higher the EER the more efficient the model and the lower your energy bill. A model with an EER of 10 should use about 20% less energy than one with an EER of 8.
Make sure that the unit is the right size for the window you plan to mount it in. Protect your back by having enough help to install the air conditioner (most are awkward and very heavy). Some air conditioners require a metal shelf, or special electrical wiring (220 volts).