The federal government requires all air conditioning and heating equipment to be rated as to efficiency. The higher the rating, the more efficient the model. For cooling, the rating is SEER (Seasonal Energy Efficiency Rating); heat pump heating is HSPF (Heating Seasonal Performance Factor) and gas furnaces are rated with AFUE (Annual Fuel Utilization Efficiency). The government’s minimum rating as of the year 2015 was raised to a minimum rating of 14. (It is comparable to mpg in a car) All of these ratings can be compared by asking the technician.