The benefits of a high efficiency furnace are lower energy consumption, quieter operating noise, more even heating and steadier temperature maintenance. Additionally, companies may offer a substantial rebate when a homeowner purchases a high-efficiency furnace.
High efficiency furnaces use at least 30 percent less fuel than furnaces that are not high efficiency. A high efficiency furnace with a lower BTU rating than a less efficient furnace can work just as well.
Furnaces manufactured in the 1980s could operate at up to about 60 percent efficiency, while further technology has developed furnaces that can operate at close to 100 percent efficiency, as of 2015.