Heating / HVAC Collection editorial
What AFUE tells you about a furnace
Efficiency is one selection factor alongside fuel, capacity, venting and duct performance.
Understanding the label
Annual Fuel Utilization Efficiency estimates the proportion of fuel energy converted into useful heat over a typical season under the applicable test. It does not state the heating capacity or predict an individual household bill.
Equipment and the building
An efficient furnace connected to leaky ducts can still deliver uneven comfort. Ask for a heating load calculation and inspect the duct distribution before assuming a like-for-like size is correct.
Condensing equipment
High-efficiency condensing units recover more heat from exhaust gases. They may require different venting, condensate drainage and site work from older units. The installation quote should identify these items.
Full cost
Compare model, fuel, efficiency, blower controls, installation, annual servicing and energy prices. A higher AFUE can reduce fuel use, but the value depends on usage and local prices.
Sources and further reading
- US Department of Energy: Heat Pump Systems
- US Department of Energy: Central Air Conditioners and Heat Pumps