You might see an EER (Energy Efficiency Ratio) number for your portable air conditioner, which measures the cooling ...

For example, a 12,000-BTU air conditioner that uses 1,200 watts of electricity has an EER of 10. Generally speaking, window AC units typically have ratings between 8 and 12.

Shopping for a window air conditioner? ... or open plan space of between 350 to 550 feet would be best served with a unit of between 9,800 and 12,500 Btu. The window air conditioners in CR’s ...

It's critical to get the right size when buying a window air conditioner. Consumer Reports explains how to do it. Plus, the best small, midsized, and large window AC units.

Our gear editors tested over a dozen window air conditioners to find the best ones that can quietly cool homes. ... a 300-square-foot room will likely need at least an 8,000-BTU air conditioner.

Using Energy Star’s chart as a guideline, we knew that an 8,000-Btu window AC is supposed to work best for rooms of up to 350 square feet, while a 12,000-Btu model is better suited for larger ...