acquainted with primary air conditioners you'll be already acquainted with the seer or seasonal energy performance ratio. Room air conditioners are rated now not on in seer however alternatively in eer or strength efficiency ratio. The eer of a given room air conditioner is calculated through dividing the cooling capability in british thermal gadgets (btu) in keeping with hour by means of the power ente r in watts. You can locate room air conditioners providing a range of cooling powers from five,500 btu in keeping with hour to fourteen,000 btu according to hour. Even as the countrywide equipment widespread requires that any room air conditioner built after 1990 to have an eer of 8. 0 or greater, and .