A furnace efficiency rating can help tell you a great deal about what to expect from a new unit you’re considering installing in your home. This metric, known as the Annual Fuel Utilization Efficiency (AFUE), is a percentage that represents the amount of useable heat generated by the furnace versus the heat that is lost in the process of combustion and venting. A higher furnace efficiency rating generally means more heat at lower monthly costs compared to a lower furnace efficiency rating.
Standard Vs. High
Today’s gas-fired home furnaces are available in basically two efficiency levels: standard and high efficiency.
- Standard efficiency units are those with AFUE ratings of at least 80%, which is the current minimum as required by the Department of Energy. This rating means that 80% of the gas is converted to heat the home, while the remainder is lost in the combustion process or vented to the outdoors along with combustion gases.
- High-efficiency furnaces have AFUE ratings of 90% and above. The percentage of available heat in these units is greater than in units with standard efficiency, as less heat is lost in the process of combustion and venting. Most high-efficiency units are two-stage furnaces that incorporate an extra heat exchanger, which recovers additional heat.
Short Term Vs. Long Term
If high-efficiency furnaces deliver more heat and lower monthly bills, why doesn’t every home have a furnace with a 90% AFUE? Here are two opposing factors that should be considered side by side to help you make an informed choice.
- The upfront purchase price of a high-efficiency unit is notably more expensive than that of a standard-efficiency furnace. In addition, installation costs of units with 90% AFUE are also generally higher than installation costs for standard-efficiency units.
- Over time, the lower monthly operating costs of a high-efficiency furnace will compensate for the higher upfront expense. In addition, higher-efficiency units generally have a longer expected service life than standard units.
For experienced professional advice to select the unit with the right furnace efficiency for your needs and budget, contact Hansberger Refrigeration and Electric Company.