Efficiency standards for all heating and cooling units manufactured in the U.S. are governed by the Department of Energy. Since as much as half of the energy used in your home goes to heating and cooling,* it helps to consider products with high efficiency ratings.
Furnaces are rated by the Annual Fuel Utilization Efficiency (AFUE) ratio, which is the percent of heat produced for every dollar of fuel consumed. Like the miles-per-gallon rating on your automobile, the higher the AFUE rating, the lower your fuel costs.
A furnace with an AFUE of 80 will turn 80% of its fuel into useable heat, while wasting about 20% of its fuel through either air leaks, inefficient burners or a less-advanced design. On the other hand, a furnace with an AFUE of 95 will convert 95% of the gas or oil it consumes into useable warmth. Any furnace with an efficiency of 90% or higher is considered high-efficiency.
Lennox offers residential furnaces with AFUE ratings ranging from the federal minimum of 80% all the way up to an industry-leading 98.7%**. The most efficient models can save you hundreds of dollars a year, compared to an older or less-efficient furnace.
*U.S. Department of Energy statistics
**Based on sound pressure levels during steady-state, high-fire and low-fire operation of Lennox SLP98UH070XV36B and leading competitive units as of July 2013 at mid-point temperature rise and minimum external static pressure when set up per Section 4.4.4 of AHRI 260-2012. Based on AFUE efficiency rating of Lennox SLP98UH090XV60C and leading competitive units listed in AHRI directory as of March 2015. Efficiency ratings established per test standard ANSI/ASHRAE 103-1993.