Heat Pump Savings Calculator
Estimate heat pump savings from fuel use, COP or HSPF2, utility rates, incentives, backup heat, and simple payback timing for bids.{{ summaryHeading }}
Review heat pump inputs
| Metric | Value | Calculation note | Copy |
|---|---|---|---|
| {{ row.metric }} | {{ row.value }} | {{ row.note }} |
| Check | Status | Bid note | Copy |
|---|---|---|---|
| {{ row.check }} | {{ row.status }} | {{ row.note }} |
Introduction:
Heating-cost comparisons only make sense after every system is reduced to the same useful heat delivered indoors. A gas furnace, oil boiler, propane furnace, electric baseboard, and heat pump all buy energy in different units. The bill may show therms, gallons, or kilowatt-hours, but the home still needs a certain amount of heat through the season.
A heat pump can lower that operating cost because it moves heat instead of creating all heat through combustion or electric resistance. A seasonal coefficient of performance (COP) of 3.0 means the heat pump delivers about three units of heat for each unit of electricity it uses. That advantage can shrink when electricity is expensive, the climate is cold, backup heat runs often, or the current fuel is cheap.
The starting fuel matters. Electric resistance heat is often the easiest case to improve because the old system and the heat pump both use electricity, but the heat pump uses fewer kilowatt-hours for the same delivered heat. Propane and heating oil cases depend heavily on delivered fuel price. Natural gas can be harder to beat when the gas rate is low and the electric rate is high, even if the heat pump is efficient.
- Delivered heat
- Useful heat after fuel heat content and current system efficiency are applied.
- COP
- Useful heat delivered divided by heat pump electricity consumed.
- HSPF2
- A seasonal heating rating in Btu per watt-hour under the current test method used for many product ratings.
- Break-even price
- The electricity price or heat pump efficiency where the new heating cost matches the current delivered-fuel cost.
- Simple payback
- Net installed cost divided by positive annual savings. It is a rough timing check, not a financing model.
Small assumptions can change the answer. A heating bill may also include cooking or water heating. A fuel delivery price may not match the season being modeled. Electricity should use the all-in marginal kWh price that rises with extra heat pump use. A quoted COP should describe seasonal heating performance for the climate and backup strategy, not only mild-weather laboratory efficiency.
A savings estimate is not an HVAC design. It does not size equipment, prove cold-weather capacity, model hourly weather, verify ducts, or decide whether electrical work is needed. It is a disciplined first pass at the cost question: how much the same delivered heat costs under the current system and under a heat pump scenario.
How to Use This Tool:
Start from the preset that best matches the retrofit, then replace every assumption with bill, rating, and bid values you trust.
- Choose an Upgrade preset. Presets fill common cases such as gas furnace, propane, oil heat, or electric baseboard replacement.
- Set Current heating fuel, Annual fuel use, and Current system efficiency. Use only the annual fuel tied to space heating when the same bill also covers water heating, cooking, or other loads.
- Enter Current fuel price in the unit shown beside the field, such as dollars per therm, dollars per gallon, or dollars per kWh.
- Select Heat pump efficiency basis. Use Seasonal COP when an audit, contractor, or model gives a seasonal value. Use HSPF2 rating when the product rating is the number available.
- Enter Electricity price, Installed project cost, and Confirmed incentives. Incentives are subtracted from installed cost before simple payback is calculated.
- Open Advanced when cooling kWh reduction, annual maintenance or comfort credit, annual backup heat cost, or Planning horizon should affect the estimate.
- Read Savings Ledger first, then check Break-even Check and Payback Timeline. If Check inputs appears, fix the named value before relying on the result.
Interpreting Results:
Total annual savings is the main operating estimate. It starts with current heating cost minus heat pump heating cost, then adds optional cooling savings and maintenance or comfort credit, and subtracts backup heat cost. A cost-increase status means the entered rates and seasonal performance do not beat the current system under those assumptions.
Savings Ledger is the audit trail. Check Delivered useful heat, Heat pump heating electricity, Net install cost, and Simple payback before comparing bids. If delivered heat looks wrong, the annual fuel use, fuel type, or current system efficiency is probably the first place to look.
Break-even Check is the best guard against false confidence. If the entered electricity price is above Break-even electricity price, savings require better COP, lower electricity price, higher current fuel cost, or larger incentives. If entered seasonal performance is below Break-even heat pump efficiency, ask for a clearer cold-weather and backup-heat case.
Payback Timeline shows cumulative net savings across the selected planning horizon. It is useful for seeing whether annual savings recover the net install cost within the years you expect to own or keep the equipment, but it does not include financing, fuel escalation, replacement timing, comfort value, or carbon value.
Technical Details:
The calculation uses delivered heat as the common base. Current fuel use is converted to Btu with the selected fuel's heat content, then multiplied by current system efficiency. The heat pump must deliver that same heat load with electricity at the selected COP or HSPF2-derived COP.
Cost per MMBtu is the comparison unit behind the break-even checks. It lets natural gas, propane, heating oil, electric resistance, and heat pump electricity be compared after unit conversion. The result still depends on seasonal assumptions, because a colder climate or more backup heat can lower the effective heat pump advantage.
Formula Core:
The main formulas convert current fuel to delivered heat, estimate heat pump electricity, and calculate annual savings and payback.
Net installed cost is installed project cost minus confirmed incentives, floored at zero. Cooling savings equal current cooling kWh multiplied by the selected reduction percentage and electricity price. Payback is shown only when annual savings are positive.
| Quantity | Rule used | Why it matters |
|---|---|---|
| Fuel heat content | Natural gas 100,000 Btu/therm, propane 91,500 Btu/gal, heating oil 138,500 Btu/gal, electricity 3,412.142 Btu/kWh. |
Creates the delivered-heat base for current and heat pump cost comparison. |
| Break-even electricity price | Current cost per MMBtu divided by heat pump kWh per MMBtu. | Shows the highest entered kWh price that would match current heating cost at the selected heat pump performance. |
| Break-even COP | Electricity cost per MMBtu at 1.0 COP divided by current delivered-fuel cost per MMBtu. |
Shows the seasonal performance needed for operating cost parity. |
| Payback status | Cost increase when annual savings are zero or negative, Strong payback through 7 years, Moderate payback through 12 years, and Slow payback above 12 years. |
Frames the timing signal without treating it as a financing recommendation. |
| Validation limits | Annual fuel use and selected heat pump efficiency must be positive; current system efficiency must be 1% to 100%; cooling reduction must be 0% to 100%; planning horizon must be 1 to 30 years. |
Prevents common zero, negative, and out-of-range inputs from producing misleading savings. |
A default electric resistance example shows the scale. 12,000 kWh at $0.16/kWh costs $1,920 and delivers about 40.95 MMBtu. At 3.2 COP, the heat pump needs about 3,750 kWh for the same heat, costing about $600. Heating operating savings are therefore about $1,320 before cooling, maintenance, backup heat, project cost, or incentives are applied.
The HSPF2 conversion is an approximation for this economic worksheet. Product ratings, installed ductwork, control settings, defrost behavior, auxiliary heat, and outdoor temperature distribution can all change seasonal performance in a real home.
Accuracy Notes:
This is an annual economic comparison, not a load calculation, installation approval, or rebate eligibility check. Treat it as a screening estimate before asking a contractor, utility program, or energy advisor for project-specific review.
- Use a full heating season or weather-normalized annual fuel use when possible.
- Use marginal electricity price, including delivery charges that rise with added kWh use.
- Keep backup heat cost separate unless the selected seasonal COP already includes that backup operation.
- Verify incentives outside the calculator before subtracting them from installed cost.
- Do not use simple payback alone to compare comfort, noise, equipment life, maintenance risk, carbon impact, or financing.
Worked Examples:
Electric baseboard replacement
With 12,000 kWh per year of electric resistance heat, 100% current efficiency, 3.2 COP, $0.16/kWh electricity, a $9,000 installed cost, and $1,500 confirmed incentives, Total annual savings is about $1,320/yr. Simple payback is about 5.7 years, and the 12-year net savings estimate is about $8,340.
Propane case with backup heat
A propane case with 650 gal/yr, 88% current efficiency, $2.70/gal fuel, 2.7 COP, $0.18/kWh electricity, $15,000 installed cost, $3,000 incentives, and $250/yr backup heat still lowers annual operating cost. The backup cost and net installed cost stretch simple payback to about 24.9 years, so Break-even heat pump efficiency is a better bid check than the status label alone.
High electric rate against low gas cost
A gas system using 700 therms/yr at 90% efficiency and $1.10/therm is hard to beat when electricity is $0.38/kWh and seasonal COP is 2.2. The result shows an annual cost increase and no payback because the heat pump delivered-heat cost is far above the current fuel cost.
Invalid efficiency value
If Heat pump seasonal COP is set to zero, Check inputs reports that seasonal COP must be greater than zero. Enter a positive COP or switch to HSPF2 rating with a valid rating before reading Savings Ledger.
FAQ:
Should I use COP or HSPF2?
Use Seasonal COP when a contractor, audit, or model gives a seasonal value for your climate and backup strategy. Use HSPF2 rating when the product rating is the number available.
Why can savings be negative?
Negative savings means the entered heat pump heating cost plus selected adjustments, such as backup heat, is higher than the current heating cost under the rates and efficiency values entered.
What fuel price should I enter?
Enter the all-in price that matches the displayed unit, such as delivered dollars per gallon for propane or oil, dollars per therm for gas, or dollars per kWh for electric resistance heat.
Are rebates and tax credits looked up automatically?
No. Confirmed incentives is a manual dollar field. Enter only incentives that apply to the equipment, location, installation date, and household eligibility.
Why does planning horizon matter?
The Planning horizon changes lifetime net savings and the payback timeline. It does not change annual savings or simple payback.
Glossary:
- Btu
- British thermal unit, a measure of heat energy.
- MMBtu
- One million Btu, used here to compare delivered heat costs across fuels and electricity.
- Delivered heat
- Useful heat after fuel heat content and current system efficiency are applied.
- COP
- Coefficient of performance, or useful heat delivered per unit of heat pump electricity consumed.
- HSPF2
- Heating Seasonal Performance Factor 2, a seasonal rating expressed in Btu per watt-hour.
- AFUE
- Annual Fuel Utilization Efficiency, commonly used for furnace and boiler efficiency.
- Break-even electricity price
- The electricity price at which heat pump heating cost would match current delivered fuel cost.
- Simple payback
- Net installed cost divided by positive annual savings.
References:
- Heat Pump Systems, U.S. Department of Energy.
- Air-Source Heat Pumps, U.S. Department of Energy.
- British thermal units (Btu), U.S. Energy Information Administration.
- Air Source Heat Pumps, ENERGY STAR.
- Purchasing Energy-Efficient Residential Air-Source Heat Pumps, U.S. Department of Energy.