Enter Heating Data
Formula used
The calculator converts useful heating demand into current fuel input, then compares it with heat pump electric input. The central formulas are shown below.
- Current fuel units = Useful heat ÷ Current efficiency ÷ Fuel energy per unit.
- Effective COP = Seasonal COP × (1 − Climate derate).
- Heat pump kWh = Heat pump useful heat in kWh ÷ Effective COP + Auxiliary kWh.
- Annual savings = Current annual cost − Heat pump annual cost + Extra savings.
- Payback = Net project cost ÷ Annual savings.
- NPV = Sum of discounted annual savings − Net project cost.
- Emissions saved = Current emissions − Heat pump emissions.
How to use this calculator
- Enter annual useful heat demand from bills, audits, or load models.
- Select the present fuel type and enter the local fuel price.
- Add current system efficiency and annual maintenance cost.
- Enter the heat pump seasonal COP, electric rate, and backup share.
- Add project cost, incentives, carbon factors, and finance assumptions.
- Press Calculate Savings and read the result above the form.
- Use the CSV and PDF buttons to save the calculation.
Example data table
| Scenario | Heat demand | Old system | Fuel price | COP | Electric rate | Expected result |
|---|---|---|---|---|---|---|
| Gas hybrid | 60 MMBtu | 85% gas furnace | $1.45/therm | 3.2 | $0.16/kWh | Moderate savings |
| Oil replacement | 75 MMBtu | 82% oil boiler | $4.10/gallon | 3.0 | $0.18/kWh | High savings |
| Resistance upgrade | 35 MMBtu | 100% electric heat | $0.20/kWh | 3.4 | $0.20/kWh | Strong savings |
Energy Savings Heat Pump Guide
A heat pump moves heat instead of making heat from a flame. That simple difference changes the energy balance. A furnace burns fuel and loses some heat through exhaust. Resistance heat turns electricity into heat at almost one to one. A heat pump can deliver several units of heat for each unit of electricity. The ratio is called coefficient of performance, or COP. Higher COP means lower purchased energy for the same room comfort.
Why Heat Pumps Save Energy
Savings depend on useful heat demand, local rates, and seasonal efficiency. A cold home may need many million Btu each year. The old system must buy extra fuel because it is not perfectly efficient. The calculator first estimates the fuel input needed to supply that useful heat. It then estimates heat pump electricity from useful heat divided by effective COP. A climate derate can reduce COP for very cold weather. Backup heat share can cover design days or hybrid operation.
Cost Factors That Matter
Energy price is the largest driver. Cheap gas can reduce money savings, even when the heat pump uses less site energy. High oil, propane, or electric resistance costs can make savings large. Fixed service charges are not included unless you add them through maintenance fields. Incentives lower the project cost and improve payback. Annual escalation and discount rate help compare long term cash flow in today's value.
Emissions and Physics
Emissions depend on the fuel carbon factor and grid carbon factor. A heat pump can cut emissions when the grid is cleaner than the displaced fuel. The result is not automatic. A very dirty grid and low gas use can reduce the benefit. The calculator shows both current and proposed kilograms of carbon dioxide. That makes the decision clearer.
How To Read Results
Annual savings shows the first year difference after energy and maintenance inputs. Simple payback divides net project cost by annual savings. Net present value adds discounted savings across the analysis period. Break even electric rate shows how high the power price could rise before savings disappear. Use realistic inputs. Then test best case and worst case values.
Practical Planning Tips
Start with bills from a full heating season. Convert delivered fuel into annual heat demand when possible. Use a seasonal COP, not a laboratory peak value. Ask installers for expected balance point, backup share, and capacity at low outdoor temperature. Include weatherization if it reduces heat demand. Small changes can shift the final answer. This tool is best for planning. Final design still needs local load checks and equipment data.
Use the calculator as a comparison model, not a sales quote. Local duct losses, thermostat habits, and defrost cycles can change real use. Review several scenarios before choosing equipment. A conservative case protects budgets. An optimistic case shows the upside. The range is often more useful than one number.
FAQs
What is useful heat demand?
Useful heat demand is the heat delivered to the building. It is not the fuel purchased. Existing equipment efficiency decides how much purchased fuel is needed to create that delivered heat.
What COP should I enter?
Use seasonal COP when available. It should reflect real winter operation, not only lab peak efficiency. A contractor, product database, or energy audit can provide a better estimate.
Why include a cold climate derate?
Cold weather can reduce heat pump efficiency. The derate lowers the entered COP to create a more conservative seasonal estimate for colder regions or older equipment.
What is backup heat share?
Backup heat share is the portion of annual heating served by the old system or auxiliary heat. Hybrid systems often use backup during very cold hours.
Can this compare oil and propane?
Yes. Choose the correct fuel type and enter the price per gallon. The calculator uses typical energy content values for the selected fuel.
Why can savings be negative?
Savings can be negative when electricity is expensive, fuel is cheap, COP is low, or backup use is high. This means the proposed setup costs more each year.
What does break even electric rate mean?
It is the electric price where annual savings become zero. If your actual rate is lower, the heat pump may save money under the entered assumptions.
How is payback calculated?
Payback divides net project cost by first year annual savings. It is simple and useful, but it does not show cash flow timing or discounting.
What does NPV show?
Net present value estimates the value of future savings in today's money. It subtracts net project cost after discounting future annual savings.
Can I use custom fuel data?
Yes. Select custom fuel unit, enter energy per unit, price per unit, and carbon factor. This supports pellets, district heat, or local data.
Is this a final design tool?
No. It is a planning calculator. Final equipment selection should use local load calculations, equipment performance tables, duct checks, and installer guidance.