Furnace efficiency is defined by the Annual Fuel Utilization Efficiency (AFUE) rating. This rating represents the percentage of energy in the fuel that is converted to usable heat for warming your home or business. AFUE ratings apply to both electric furnaces and units that use fossil fuels such as oil or natural gas. They are a direct indication of how efficiently your furnace will operate and how much money you are likely to spend, or save, on your heating bills.In a gas furnace with an AFUE rating of 85, for example, 85 percent of the available energy in the gas fuel is converted to heat. However, 15 percent of the energy in the fuel will be wasted. This lost 15 percent will escape out the flue, unused, or will seep out elsewhere in the furnace system.Furnaces with higher AFUE ratings are more efficient, meaning they make better use of the fuel they consume to generate heat. Less fuel is wasted as the furnace operates, and less fuel is needed to attain the desired heating levels than with a lower-AFUE unit. Reduced energy waste and less fuel consumption translates to measurable savings on your winter heating bills.According to the U.S. Department of Energy, if you replace an existing AFUE 50 furnace with an AFUE 80 unit, you could save almost 25 percent on your heating fuel costs. Replacing an AFUE 50 unit with an AFUE 95 amounts to almost 50 percent savings.Government standards mandate that new fossil-fuel warm-air furnaces carry a minimum AFUE 78 rating. Electric furnaces generally have an AFUE rating of 95 or higher.High-efficiency, high-AFUE furnaces generally cost more than lower-AFUE models, but the substantial savings on heating bills can offset the expense of a better furnace relatively quickly.Air Assurance has more than 30 years of experience serving heating and air conditioning customers in the Tulsa and Broken Arrow areas. We carry a full line of high-efficiency furnaces and can help you decide which model at which AFUE rating is best for your needs. Contact us today.Our goal is to help educate our customers about energy and home comfort issues (specific to HVAC systems). Air Assurance services Tulsa, Broken Arrow and the surrounding areas. Visit our websiteto see our current promotionsand get started today! Photo courtesy ofShutterstock.