1 · Home & fuel
How much heating you buy per year, and what each fuel costs where you live.
Enter your ZIP and we’ll fill typical equivalent full-load heating hours for your climate, plus your state’s average electricity rate. Every value stays editable. Nameplate input is the BTU/h figure on the furnace’s rating plate; use your bill’s total cost ÷ therms for the delivered gas price.
Add up therms on your winter gas bills, minus a summer month × 12 for water heating & cooking. Rough guide: mild climate ≈ 300, moderate ≈ 600, cold ≈ 900–1,100 therms/yr. Use your bill's total cost ÷ therms for the delivered price.
Winter peak minus your summer month is treated as heating gas. The $/therm converts dollars to energy so furnaces and heat pumps compare fairly.
Used when the replacement is a heat pump. Auto-filled from your ZIP’s state average; your bill’s total ÷ kWh gives the real all-in rate.
2 · Current furnace
From its nameplate AFUE, or estimated from its age.
Shown for context in results; edit if you have quotes or history. Furnaces past ~15–20 years also carry heat-exchanger crack risk — a safety retirement, not just a cost one.
3 · Replacement system
The system you’re considering — type, efficiency, quoted price, and rebates.
Estimated yearly savings with the new system
$0
about $0 per winter month off the fuel bill
—
Payback (yrs)
$0
15-yr savings
0%
Heating cost cut
At today's fuel prices. Actual savings vary with weather, usage, and installation quality.
Environmental impact
0 tons of CO₂ avoided
over 15 years
Annual heating cost — today vs. new system
Yearly fuel cost at the prices entered, with lifetime savings and payback. A heat pump buys electricity; a furnace buys gas.
Keep it vs. replace it
Cumulative cost of ownership over the next 15 years.