Furnace System GuideFurnace tool
AFUE Upgrade Savings Calculator
Estimate annual fuel savings from moving to a higher AFUE furnace using your current heating cost and both efficiency ratings.
Screening estimate only.A professional Manual J load calculation is authoritative for final furnace sizing and equipment selection. Confirm every result with a licensed HVAC professional.
Screening result
Fine Print and Sources
Screening estimate only. These tools use only the values you enter and simple planning math. A professional Manual J load calculation is authoritative for equipment sizing, room loads, and final purchase decisions. Confirm with a pro before you buy.
Method: annual savings equal your current heating cost times one minus the ratio of current AFUE to new AFUE. This estimates fuel savings only. Simple payback depends on the installed cost of the new furnace, which is not included here.
- US Department of Energy furnaces and boilers: explains furnace efficiency, AFUE, and why proper sizing and a load calculation matter.
- Energy Star furnaces: describes AFUE tiers and how higher-efficiency condensing furnaces reduce fuel use.