Heating and air conditioning systems have improved their energy efficiency vastly over the past 20 years. Today, the US Department of Energy’s ENERGY STAR program certifies the most efficient of these systems, which sometimes perform at 40% greater efficiency than older models.
The high-efficiency furnace is one of the big success stories in energy-friendly comfort. For many years, the standard efficiency of most furnaces was between 70 to 80% AFUE, meaning that 70 to 80% of the furnaces’ fuel source was converted to heat, the rest lost to exhaust. Today, there are high-efficiency furnaces that score higher than 95% AFUE.