By Betty Stephens
High-efficiency furnaces provide exceptional value, and can be used with natural gas or converted to propane. In addition, the furnace also works with your outdoor system to circulate cool air in summer, helping you stay comfortable all year long.
95% AFUE furnaces save home owners cash in the long run, even without the tax credit. "Simply place, with a 95% AFUE furnace, for every dollar you commit on heating power, 95 cents of that dollar is utilized to warm your residence. 95% AFUE furnaces with a variable-speed blower are even a lot more effective. The variable-speed blowers used in the 95% AFUE Variable-Speed Furnace usually need up to 75 % less electricity than a common motor. Due to the fact a furnace's blower also operates with the home's cooling method to circulate air, customers encounter elevated efficiency year-round.
The condensing furnace is so efficient and extracts so much heat from the combustion process that its exhaust vent / flue is just warm to the touch, not “burn your fingers hot” like a conventional furnace. The primary difference between the conventional furnace and the 95% furnace is in the dual heat exchangers.
High-efficiency furnaces feature a second combustion chamber, which captures exhaust gases and moisture before it exits into the flue. This second chamber condenses the gaseous by-products to form a liquid, and then extracts any remaining heat. This heat is then transferred into a second heat exchanger, which supplements the primary heat exchanger and helps to heat the air. The small amount of remaining waste is exhausted from the home through a small flue or even a simple pipe in the wall.
Anatomy of a High Efficiency Condensing Furnace
Furnace Efficiency Ratings
The existing furnace in your home, or maybe one you are considering purchasing, can be organized into these efficiency categories.
• Low Efficiency Furnace: 55% to 72% AFUE
• Low Efficiency Furnace: 78% AFUE
• Standard / Mid Efficiency Gas Furnace: 80% to 83% AFUE
• High Efficiency Gas Furnace: 90% to 98% AFUE
The metric used to measure furnace efficiency is called the AFUE rating. AFUE is an acronym for Annual Fuel Utilization Efficiency and it measures the amount of fuel converted to heat in the space in proportion to the amount of fuel which enters the furnace. The higher the AFUE the more efficient the furnace is.
Homes today are required to have an AFUE rating of at least 78% but furnaces of this low AFUE are typically found in manufactured homes. For a furnace to meet the DOE's Energy Star program, it must be a high efficiency furnace with an AFUE of 90% or higher.