Understanding AFUE Ratings

According to the U.S. Department of Energy (DOE), heating and cooling the average home in the U.S. accounts for about 56% of home energy use, making it the largest energy expense for most households. It is important then to have a way to know just how energy efficient home heating and cooling appliances are when purchasing them for your home. To give consumers an objective measure of how efficient fuel fired heating systems are, the AFUE rating was established.

AFUE stands for "Annual Fuel Utilization Efficiency" and is expressed as a percentage. It is not an absolute rating of the energy efficiency of a piece of equipment per se, but it is intended to indicate what the overall efficiency would be in a typical application over the course of a year. This is what people really want to know when they purchase heating equipment, so they can get an idea of what it is going to cost to operate compared to what they have now.

For instance, if a furnace has an AFUE rating of 50%, what that means is that for the energy value of the fuel to operate that furnace over the course of a typical year, only 50% of the energy went to heat the home. That sounds really dismal, but up until minimums were established for home heating systems, that's what you might have been stuck with. Now the minimum AFUE rating for a furnace is 78% as established by the U.S. government. There may still be some of those old systems out there presently in use, but any new furnaces installed have to meet the minimum AFUE rating. If you had a furnace with a 50% AFUE rating and replaced it with one that has an 80% AFUE rating, you can expect to save about 37% on your home heating bill over the course of a year.

The U.S. government may have set minimum standards, but to promote greater energy efficiency the DOE and the U.S. Environmental Protection Agency (EPA) have developed the ENERGY STAR program. For an equipment manufacturer to earn the ENERGY STAR seal, they have to comply with the standards that ENERGY STAR has established for energy efficiency.

The current standard is ENERGY STAR 2.0 as of October 27, 2006, which is higher than the U.S. government's established minimum standard. For a furnace manufacturer to meet the ENERGY STAR 2.0 standard, a gas-fired furnace would have to have an AFUE of at least 90%, and an oil-fired furnace would have to deliver an AFUE rating of 83%. For instance, if you had a furnace with an AFUE of 80% and you replaced it with a ENERGY STAR Furnace with and AFUE of at least 90%, you could expect to save 11% on your home heating bill over the course of a typical year.

Check to see if your home heating and air conditioning dealer will offer ENERGY STAR equipment. They will be able to help you understand what the energy ratings of the equipment mean, and work with you to determine if it makes sense to upgrade the heating and cooling equipment for your home.

Bardi Heating and Air conditioning is an Atlanta area HVAC contractor specializing in design and installation of air conditioning systems for residential and commercial project of any size. To learn more their services please visit this author's website at http://www.Bardi.com