If you’re furnace shopping or plan to be soon, you may find yourself asking, “What is AFUE?” It’s a term you’ll certainly encounter if the furnace you’re considering utilizes natural gas as its heating fuel.
What Is AFUE?
AFUE stands for Annual Fuel Utilization Efficiency. It’s a percentage that represents the amount of heat produced by a gas furnace versus the amount lost in the process. The higher the AFUE percentage, the more efficient the furnace. Since less gas is consumed to maintain comfortable temperatures, monthly operating costs are lower.
What Is AFUE Average Rating?
The federally mandated minimum standard AFUE rating for a gas furnace is 80%. This means that 80% of generated heat goes into warming your house, while 20% is lost in the heating process. In these average-efficiency gas furnaces, most heat loss occurs in hot combustion gases that are exhausted up the vent and out of the house.
What Is AFUE High-Efficiency Rating?
Units with an AFUE rating of 90% or above are considered high-efficiency furnaces. These two-stage models reduce lost heat by incorporating a secondary heat exchanger that extracts extra heat from exhaust gases before they are vented. This provides more warmth with less gas consumption and lower heating costs.
Factors to Consider
- While a standard-efficiency AFUE 80 furnace costs more to operate due to higher monthly gas bills on a continuing basis, its upfront purchase price is considerably lower than a high-efficiency model.
- A high-efficiency furnace with an AFUE rating above 90% uses gas more efficiently, thus lowering monthly operating costs. However, the high-efficiency unit is more expensive to purchase than a standard furnace.
- To make an informed buying decision, the homeowner must consider the time frame necessary for lower monthly gas bills to compensate for the steeper initial price of the high-efficiency model. A professional HVAC contractor can help evaluate these factors — and other related issues such as insulation and air sealing — to reach the best option for your home.
For more answers to the question “What Is AFUE?”, contact the heating pros at Detmer and Sons.