Heating Run Cost Estimator

This private worksheet helps you estimate your furnace's run cost based on your own fuel rate, furnace efficiency, and estimated run hours. It does not use averages or predict your bill. Your inputs stay on your device. For an accurate assessment, have a professional evaluate your system's actual efficiency and runtime.

Minneapolis–St. Paul, MinnesotaResearch checked July 31, 2026Source-linked educational guide — verify current details and obtain a professional assessment when needed

Quick, low-risk steps

Gather your latest utility bill to find your fuel rate per unit (e.g., per therm or kWh).

Check your furnace's AFUE rating on its nameplate or manual.

Estimate daily run hours based on your thermostat settings and weather.

Enter your numbers into the worksheet below to see a rough cost scenario.

Compare different efficiency ratings or fuel rates to understand potential savings.

How to Use This Worksheet

This tool is a simple calculator that multiplies your fuel rate by estimated consumption. It does not account for duct losses, variable-speed motors, or thermostat setbacks unless you adjust the inputs.

All calculations happen in your browser. We do not see, store, or share your numbers. The results are only as accurate as the information you provide.

Enter your fuel cost per unit from your bill.
Input your furnace's AFUE (e.g., 80 for 80%).
Estimate how many hours per day your furnace runs.
The worksheet shows a daily and monthly cost estimate.
Adjust inputs to see how changes affect cost.

Understanding Your Inputs

Fuel rate: This is the price you pay per unit of fuel. For natural gas, it's often in therms; for electricity, kilowatt-hours. Check the supply or generation charge on your bill, not the total divided by usage.

AFUE (Annual Fuel Utilization Efficiency): This percentage tells you how much fuel becomes heat. An 80 AFUE furnace turns 80% of fuel into heat; the rest is lost. Higher AFUE means lower fuel use for the same heat.

Find your fuel rate on your utility bill under 'supply charge' or similar.
AFUE is on the furnace nameplate or in the manual.
If you can't find AFUE, use 80% for older furnaces, 90%+ for newer condensing models.
Runtime is tricky—a professional can measure it, or you can estimate from thermostat cycles.
Remember: this is a rough estimate, not a bill prediction.

Limitations of This Estimator

This worksheet does not replace a professional energy audit or Manual J load calculation. It cannot account for your home's insulation, air leaks, duct condition, or thermostat programming.

Actual costs vary with weather, fuel price changes, and system maintenance. A dirty filter or failing part can increase runtime and cost without being reflected here.

Does not include fixed monthly charges from your utility.
Assumes steady-state efficiency; real furnaces cycle on and off.
Cannot model two-stage or modulating furnaces accurately without detailed runtime data.
Ignores heat pump backup or dual-fuel systems.
For a precise cost analysis, ask a professional to perform a combustion efficiency test and inspect your ductwork.

Next Steps After Estimating

If your estimated cost seems high, consider having a professional tune-up. A clean burner and proper airflow can improve efficiency. Also, check your filter and seal obvious duct leaks.

When comparing quotes for a new furnace, use this tool with the AFUE of proposed models to see potential fuel savings. Remember that installation quality and sizing matter as much as efficiency.

Schedule a professional maintenance visit if your furnace hasn't been serviced in over a year.
Ask your technician to measure actual runtime or install a runtime meter.
Get multiple quotes and compare not just price, but efficiency and warranty.
Check for utility rebates on high-efficiency furnaces in your area.
Consider a programmable thermostat to reduce runtime when you're asleep or away.

What homeowners ask next

How accurate is this cost estimator?

It's a rough estimate based on your inputs. Actual costs vary with weather, fuel price changes, and your furnace's condition. For a precise analysis, consult a professional.

Where do I find my fuel rate?

Look at your utility bill for the supply or generation charge per unit (e.g., per therm for gas, per kWh for electricity). Do not use the total bill divided by usage, as that includes fixed charges.

What if I don't know my furnace's AFUE?

Check the nameplate on your furnace or the owner's manual. If you can't find it, use 80% for older non-condensing furnaces or 90%+ for newer condensing models as a rough guess.

Need an on-site professional?

Use the guide and worksheet first so you can describe the situation and compare the full scope. A referral is optional; you can also contact a licensed local provider directly.

Referral matching is not enabled yet.

We have not enabled a provider route for this site. Use the checklist to contact and verify local providers yourself; urgent hazards should go to the appropriate emergency or public service.