Deciding whether a heating or cooling system should be replaced before a house goes on the market or helping a buyer determine the value of a current system in a home they are looking to purchase can be difficult. While your seller/buyer should always consult an expert before making any decisions, it is important for you to know the basics when it comes to the efficiency of heating and cooling systems so you can guide your client.

The standards for energy efficiency are set by the U.S. Department of Energy and ratings are assigned to every piece of heating and cooling equipment, which must appear on the products. Familiarizing yourself with these ratings will help you to be more knowledgeable about the equipment you may face in homes throughout Fairfield County.

SEER (Seasonal Energy Efficiency Ratio): This is how air conditioners and heat pumps are rated. The higher the SEER number, the greater the energy efficiency. Currently, the approved minimum SEER rating is 13.0, while the highest SEER rating available is 21.0.

HSPF (Heating Seasonal Performance Factor): While a heat pump’s cooling efficiency is measured by SEER, HSPF determines its heating efficiency. The most efficient heat pumps have an HSPF between 8.0 and 10.0.

AFUE (Average Fuel Utilization Efficiency): This is the measurement of efficiency of gas and oil-fired heating equipment. It’s shown in percentages and the number indicates how much fuel is used to heat a house – and how much is wasted. For example, a 79.5% AFUE means that 20.5% is wasted. So, the higher the number, the better the efficiency and the least waste. Currently, the following are the minimum AFUE ratings for heating equipment installed today.

  • Gas-Fired Furnace: 90%
  • Oil-Fired Furnace: 83%
  • Electric Furnace: 78%
  • Gas-Fired Hot Water Boiler: 82%
  • Gas-Fired Steam Boiler: 80%
  • Oil-Fired Hot Water Boiler: 84%
  • Oil-Fired Steam Boiler: 82%


Our Comfort Specialists have years of experience in equipment; rely on them to determine the value of a system or to give advice about replacement.



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