Homeowner planning tool
AFUE furnace savings calculator
Estimate how a different furnace efficiency rating changes fuel cost when heating demand and fuel price stay the same.
Your inputs
Starts with example figures. Replace them with your own values; results update as you type. These examples are not equipment recommendations or current utility prices.
Example calculation
Sample estimate
- Current annual heating fuel cost
- $1,200
- Proposed annual heating fuel cost
- $1,000
- Estimated annual savings
- $200
Check every input and read the assumptions below. Unchanged fields may still contain example figures.
What the result means
Assumptions and limits
This estimate excludes equipment cost, maintenance, electricity use and changes in fuel price or heating demand. It does not calculate payback. Negative savings mean a higher modeled fuel cost.
Furnace servicesHow this calculator works
Proposed annual fuel cost = current annual heating fuel cost × current AFUE ÷ proposed AFUE. Estimated savings = current cost minus proposed cost.
Before you decide
What your results mean
Use the result with its assumptions and limitations.
Does the example show installation payback?
No. It holds heating demand and fuel price constant to compare fuel conversion efficiency. Equipment cost, financing, maintenance, electrical use and future fuel prices are excluded. Change the example’s fuel-spending and AFUE inputs; a modeled fuel saving is not the payback period for a quoted project.
How does the AFUE example work?
For an illustrative annual heating-fuel cost of $1,000, moving from 80% to 96% AFUE at unchanged demand and fuel price gives about $833 in modeled fuel cost. This is arithmetic under stated assumptions, not a service price or a bill forecast.
Does the result calculate replacement payback?
No. Equipment cost, maintenance, electrical use and changes in demand or fuel price are not included. Compare those separately when reviewing furnace replacement.
Your next step
Discuss your home’s equipment
Bring the estimate and your questions. Equipment selection needs more information about your home than a calculator can collect.
