Calculator Inputs
Example Data Table
| System | Unit | Price | Energy MMBtu / Unit | Efficiency or COP | Fixed Monthly Cost |
|---|---|---|---|---|---|
| Natural Gas Furnace | therm | $1.40 | 0.100000 | 0.95 | $15 |
| Air Source Heat Pump | kWh | $0.16 | 0.003412 | 3.00 | $10 |
| Heating Oil Boiler | gallon | $4.00 | 0.138500 | 0.86 | $8 |
Formula Used
Useful heat per unit = fuel energy content × efficiency or COP.
Units needed = annual useful heat demand ÷ useful heat per unit.
Variable cost = units needed × fuel price.
Annual fixed cost = fixed monthly cost × heating months.
Total annual cost = variable cost + annual fixed cost.
Cost per useful MMBtu = total annual cost ÷ annual useful heat demand.
Estimated demand = UA × heating degree days × 24 ÷ 1,000,000 × design margin.
How to Use This Calculator
Enter annual heat demand directly, or estimate it from heating degree days and building heat loss. Then adjust each fuel price, energy content, and system efficiency. Select a baseline system for savings comparison. Press calculate to rank systems. Use CSV or PDF buttons to export the same calculation.
Home Heating Cost Comparison Guide
Heating cost is a physics problem and a budget problem. Each fuel stores energy in a different unit. Your heater also wastes some energy before warmth reaches the room. This calculator converts every fuel into useful heat. Then it compares the yearly cost on the same demand basis.
Why Delivered Heat Matters
A gallon, therm, cord, or kilowatt hour cannot be compared alone. The useful value depends on energy content and seasonal performance. A furnace with 90 percent efficiency delivers less heat than the fuel contains. A heat pump can deliver more heat than its electric input because it moves heat from outside air.
Main Cost Factors
The biggest factor is annual heat demand. Large homes, poor insulation, and cold climates need more heat. Fuel price is next. Unit energy content also matters. The final factor is system performance. This includes AFUE, combustion efficiency, electric resistance efficiency, or heat pump COP.
Using Efficiency Correctly
Enter furnace or boiler efficiency as a decimal. For example, 95 percent becomes 0.95. Enter electric resistance as 1. Heat pump performance should use seasonal COP. A COP of 3 means one unit of electricity supplies three units of room heat.
Interpreting Results
The table ranks systems by annual cost. It also shows units used and cost per delivered MMBtu. The cheapest fuel is not always the best choice. Fixed charges, maintenance, equipment cost, safety, and local supply can change the decision.
Physics Behind The Tool
The calculation starts with heat demand in MMBtu. It divides demand by useful heat per purchased unit. Useful heat equals fuel energy content times performance. Units used are then multiplied by price. Monthly fixed fees can be added for a fair annual estimate.
Better Planning Tips
Use recent utility bills when possible. Adjust prices for your location. Keep efficiency values realistic. Compare several heating loads if your insulation may improve. Run one scenario before upgrades and another after air sealing. This shows payback more clearly. For heat pumps, test lower COP values in very cold weather. For wood or pellets, include delivery and storage costs. The best answer is the option with dependable comfort and affordable useful heat. Over the full heating season safely.
FAQs
What does this calculator compare?
It compares annual heating cost for several fuel choices. It uses heat demand, fuel price, energy content, efficiency, fixed costs, and emissions.
What is annual useful heat demand?
It is the heat your home needs after losses are considered. The calculator uses MMBtu as the common comparison unit.
Can I compare heat pumps with furnaces?
Yes. Enter heat pump seasonal COP as performance. Enter furnace AFUE or efficiency as a decimal, such as 0.95.
Why is COP higher than one?
A heat pump moves heat instead of only making heat. That allows delivered heat to exceed the electric energy input.
What is UA in the estimate method?
UA is the building heat loss rate. It means Btu lost per hour for each degree F of indoor outdoor difference.
Should fixed monthly charges be included?
Yes, when they apply only because you use that heating source. They make annual comparisons more realistic.
Why do fuel energy values differ?
Each fuel stores different heat per unit. A therm, gallon, ton, and kWh cannot be compared without conversion.
Are emissions exact?
No. Emissions are estimates. Edit the pounds per unit field if your supplier gives a better local value.