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heat pump cost calculator helps you turn a practical question into a calculation you can inspect. A result is only useful when you understand what went into it: the units, the period covered, the assumptions and the costs or constraints left outside the model. This 2026 guide explains the method behind Heat Pump vs Gas Furnace Seasonal Cost Calculator, walks through the calculator’s own example and shows how to compare a second scenario without confusing an estimate with a guarantee. You can follow the steps even if you have never used this type of tool before. Start with the example, replace the inputs with your own evidence and keep a note of the assumptions that could change the decision.
Try the calculator with your own figures →
Before you enter numbers
Gather the records that describe the situation you are actually comparing. Use one consistent currency and time period for monetary inputs. Keep measured quantities separate from estimates: a recent bill, a supplier quotation or a recorded average is stronger evidence than a number copied from an unrelated project. Where the future is uncertain, use a range rather than quietly treating one guess as a fact. Write down which inputs came from documents and which were assumptions. This makes your comparison easier to update later.
heat pump cost calculator: Formula and assumptions explained
Enter temperature bands using manufacturer COP and capacity data together with an independently assessed home heat load and hours per band. The heat pump supplies the smaller of load and capacity; gas or electric resistance supplies the shortfall. Divide delivered heat by COP for electricity, and by furnace efficiency and 29.300111 kWh per therm for gas. Seasonal COP is heat-weighted through total heat divided by total input. A thermal balance point is interpolated only when capacity crosses load once in your bands. HSPF2 is not treated as a temperature-specific COP. Emissions require user-supplied factors.
heat = load × hours; HP heat = min(load, capacity) × hours; HP electricity = HP heat / COP; gas therms = gas heat / (29.300111 × furnace efficiency)
Worked example: read the results
For a temperature bin with 8 kW demand over 600 hours and heat-pump capacity 6 kW, the pump supplies 3,600 kWh of heat and backup supplies 1,200 kWh. At COP 2 the compressor uses 1,800 kWh of electricity. Repeat for each temperature bin, then sum costs. A seasonal HSPF 2 rating cannot replace the temperature-specific COP. Check the manufacturer’s performance table and a professional heat-load assessment rather than estimating capacity from floor area alone.
Example inputs: check every unit
These are the calculator’s reproducible starting values, not recommended market rates. Replace them before making a real decision. A zero can mean a genuine absence, but it must not stand in for information you have not collected. For a conditional field, first check whether that part of the scenario applies. Keep the same assumptions when checking the example by hand.
- Electricity rate per kWh: 0.2
- Gas rate per therm: 1.5
- Gas furnace efficiency: 90 %
- Backup heat for capacity shortfall: gas
- Include emissions estimates: No
- Electricity emissions factor: 0 kg/kWh
- Gas emissions factor: 0 kg/therm
| Outdoor temperature | Hours in temperature band | Heating load in this band | Heat pump COP in this band | Heat pump capacity in this band |
|---|---|---|---|---|
| -10 | 600 | 8 | 2 | 6 |
| 0 | 1000 | 5 | 3 | 6 |
| 10 | 500 | 2 | 4 | 7 |
Worked example: read the results
The figures below are calculated from the inputs above using the same engine as the interactive tool. Monetary examples use USD as a neutral label; changing the currency selector does not perform exchange-rate conversion. Small differences in the last decimal can come from display rounding. Compare the meaning and units of an output before comparing its size. A larger result is not automatically a better outcome.
- Heat pump plus backup cost: 811.592 USD
- Gas-only heating cost: 614.332 USD
- Seasonal savings: -197.26 USD
- Heat pump seasonal COP: 2.58296
- Cost break-even COP: 3.51601
- Interpolated thermal balance point: -3.33333 °C
How to compare a second scenario
Save the starting calculation, then change one uncertain input while leaving the others unchanged. Record the difference in the main output and explain what caused it. Next, test a realistic unfavorable case rather than only an optimistic case. If your decision reverses after a small change, investigate that input more carefully. Do not combine a low cost from one supplier with a performance claim from a different product unless both can actually occur together. When several assumptions move together, describe the combined scenario clearly rather than presenting it as a precise forecast.
A practical checking routine
Read the field label before copying a number. Check whether the value is per item, per month, per year or a percentage. Keep a copy of your source records. Recalculate one simple part manually to catch a unit error. Review warnings instead of hiding them with a convenient number. Finally, ask whether an important constraint is outside the model. A mathematically correct estimate can still be unsuitable if the inputs describe the wrong situation.
What this 2026 estimate can and cannot tell you
A calculator is most helpful when you have a clear question and comparable inputs. Use this guide to understand the calculation, then use the interactive version to explore your own case. The year in the title identifies this edition of the guide; it does not make an example value an automatically updated 2026 benchmark. Fees, tariffs, contracts, product performance and personal circumstances can change independently of the arithmetic. Where relevant, check the current primary source for your location and the exact product or account involved. Keep any decision based on a forecast provisional until you have checked the main uncertainties. If two scenarios are close, the difference may be less important than an omitted cost, a measurement error or an operational constraint. Record the assumptions behind your preferred option so that a later change can be traced, rather than starting again with an unexplained total.
Frequently asked questions
Are the example rates current market prices?
No. Example inputs demonstrate arithmetic, not live prices, tax rules, salary surveys or sponsor benchmarks. Enter a dated quote, bill, manufacturer specification or verified fee schedule that applies to your situation. Compare a conservative and an optimistic scenario separately.
Why is a result not determined?
Some calculations have no meaningful value when a denominator is zero, savings are non-positive, a target cannot be reached or your data do not bracket an intersection. The tool leaves that result undetermined instead of displaying infinity or inventing a recommendation. Check the method and your inputs.
Does the calculator save my information?
Inputs are calculated in your browser without an account. This calculator does not automatically save inputs. A copied calculation link contains the entered numeric assumptions and rows; anyone with that link can read them. Share only figures you are comfortable making visible. Currency changes relabel amounts without converting them.
Why does changing one input change the answer?
The output depends on the combination of quantities, rates and assumptions described in the method. Recheck the units and compare one change at a time using the worked example as your baseline.
Sources and scope of this guide
Sources explain the underlying concepts, not an endorsement of this website or its results. Method review: 20 October 2026.
Try the calculator with your own figures
Open the calculator, load the example and replace the inputs with your own figures. Compare one alternative before choosing your next step. Use the related tools below when you need to explore a separate part of the same decision.
Heat Pump vs Gas Furnace Seasonal Cost Calculator →