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Washington Energy Services has provided home comfort solutions to Puget Sound homeowners since 1957.

EER, SEER, AFUE – Gesundheit! Understanding Energy Efficiency Ratings

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Room Air Conditioners: EER

While we don’t sell single-room air conditioners, you may have seen or heard this term while researching air conditioning. A room air conditioner’s efficiency is measured by the energy efficiency ratio (EER). The EER is the ratio of the cooling capacity (in British thermal units [Btu] per hour) to the power input (in watts). The higher the EER rating, the more efficient the air conditioner.

Heat Pumps & Air Conditioners: SEER

The seasonal energy-efficient ratio, also known as SEER, is typically used for air conditioners and heat pumps. The SEER represents the ratio of cooling output to electrical power used as an input.

The US government requires that residential systems manufactured after 2005 have a minimum seer rating of 13 with the exception of window units. A highly efficient heat pump or air conditioner will have the SEER rating between 14 and 18.

There’s a real benefit to upgrading from older, less efficient models to higher SEER equipment. For example going from a 9 SEER to a 13 SEER unit, electrical power use is reduced by 30%. That can lower your energy bills by hundreds of dollars per year (depending on use).

Furnaces: AFUE

Every furnace is rated on its efficiency; in fact all heating sources can be compared using a measure called annual fuel utilization efficiency – AFUE.

Some examples:

  • Heating with firewood has an efficiency rating of between 45 and 65%, depending on your stove/fireplace. That means 45 to 65% of the wood turns into heat, and the rest is just nice to look at.
  • An 80% a AFUE furnace turns 80% of fuel into a heat and 20% is lost.

The AFUE range for furnaces is very broad. There are gas and propane furnaces that are only 55% efficient at using their fuel, and there are natural gas furnaces that are over 97% efficient in using their fuel. You can imagine the amount you would save on your heating costs using highly efficient new burning furnace. Most older homes in the Northwest have 80% AFUE furnaces and upgrading to a 97% AFUE furnace would reduce heating costs by 15%.

Both the SEER and AFUE fuel utilization measures are used by local utilities in creating their rebate programs. Only the most energy efficient models will qualify for these rebates. Our home energy specialist will know which units will qualify. To speak to a Home Energy Specialist about Furnaces or Heat Pumps please call 800-398-HOME (4663) or schedule your free estimate by clicking here.