What do heating and cooling energy efficiency ratings mean?

The HVAC (heating, ventilation, air conditioning) world is full of acronyms! Many of them refer to efficiency ratings for heating and cooling equipment. These numbers are pretty important to consumers, as they tell you a great deal about the unit’s energy consumption and operating costs – but they don’t mean a thing if you don’t understand them. We’ve decoded heating and cooling energy efficiency ratings so you’ll know exactly what the acronyms are trying to tell you.

SEER (Seasonal Energy Efficiency Ratio)

• Measures cooling efficiency of air conditioners and heat pumps.
• SEER = Total cooling output during typical annual usage / total energy input for the same period. Cooling output is represented by Btu (British thermal units) and energy input is measured in watt-hours.
• A unit’s SEER is calculated using a range of conditions to best represent the average U.S. residential usage.
• Higher SEER ratings mean greater energy efficiency, which translates to increased energy savings for users.
• New air conditioners and heat pumps are required by law to have a minimum of 13 SEER.
• The highest SEER central air conditioners on the market now are 20 to 23 SEER.

EER (Energy Efficiency Ratio)

• Measures a cooling system’s efficiency.
• EER = cooling output / electrical input. EER = Btu / watts.
• A unit’s EER is measured using set indoor and outdoor temperatures, as well as 50% relative humidity. This rating more closely represents a peak load rating versus the seasonal rating offered by SEER.
• Higher EER equals higher efficiency.

AFUE (Annual Fuel Utilization Efficiency)

• Measures the efficiency of a gas or oil furnace.
• A furnace’s AFUE is a percentage that describes the amount of fuel consumed and wasted to create heat.
• For example, if the AFUE is 90%, 90% of the fuel consumed by the furnace is converted to heat and 10% is wasted and expelled out the chimney.
• The most energy efficient furnaces in today’s market have 97% to 98.5% AFUE.

HSPF (Heating Seasonal Performance Factor)

• Measures the heating efficiency of a heat pump.
• This is a seasonal measure, sometimes considered an averaged factor representing the total heating season.
• HSPF = all yearly heating requirements (including backup heat provided by a furnace or other heating unit) / total electric power consumed. HSPF = Total Btu / Total watts
• Higher HSPF means higher efficiency, and lower energy expenses.
• New heat pumps are required to have a minimum HSPF of 7.7.
• The highest HSPF heat pumps on the market are 10 to 13 HSPF.

For friendly and professional advice on the sales, service and maintenance of HVAC equipment; contact Parkers Heating and Cooling today or call us at 615-355-9137.