Energy prices
What a delivered million BTU costs, in your state
Fuel prices are quoted in units nobody can compare — cents per kilowatthour against dollars per thousand cubic feet. Converting both to the cost of a million BTU actually delivered into the water, after the equipment's efficiency, makes the comparison honest. That single number decides most of the equipment argument.
The conversion chain, in full
Nothing here is hidden, so you can check it:
- Electricity. 3,412 BTU per kilowatthour. A million BTU is 293 kWh at the wall. Divide by the coefficient of performance for a heat pump; do not divide at all for resistance, whose coefficient is exactly 1.
- Natural gas. 1,036 BTU per cubic foot, so an Mcf carries 1,036,000 BTU, which is 10.36 therms. Divide by the heater's thermal efficiency.
- Propane. 91,452 BTU per gallon, then divide by thermal efficiency.
Cost per delivered million BTU, on your numbers
The two prices default to your state's published averages. Replacing them with the marginal rate off your own bill is the single biggest accuracy improvement available on this site.
Heat pump $9.55 / MMBtuelectricity divided by the seasonal COP
Natural gas $21.87 / MMBtugas divided by thermal efficiency
Propane $35.66 / MMBtunational price; replace with your delivered price
Electric resistance $44.64 / MMBtuno efficiency divisor exists
Every state, ranked by heat-pump running cost
| State | Electricity | Natural gas | Heat pump $/MMBtu | Gas $/MMBtu | Resistance $/MMBtu | Cheaper to run |
|---|---|---|---|---|---|---|
| UT | 12.96¢ | $10.19 | $8.12 | $12.00 | $37.98 | heat pump |
| NV | 13.60¢ | $13.14 | $8.53 | $15.47 | $39.86 | heat pump |
| MO | 13.68¢ | $14.94 | $8.58 | $17.59 | $40.09 | heat pump |
| NM | 14.12¢ | $9.83 | $8.85 | $11.57 | $41.38 | heat pump |
| LA | 14.15¢ | $17.38 | $8.87 | $20.46 | $41.47 | heat pump |
| AR | 14.36¢ | $19.25 | $9.00 | $22.66 | $42.09 | heat pump |
| TN | 14.47¢ | $11.84 | $9.07 | $13.94 | $42.41 | heat pump |
| WA | 14.95¢ | $17.62 | $9.37 | $20.74 | $43.82 | heat pump |
| KY | 14.98¢ | $14.23 | $9.39 | $16.75 | $43.90 | heat pump |
| FL | 15.17¢ | $25.48 | $9.51 | $29.99 | $44.46 | heat pump |
| AZ | 15.23¢ | $18.58 | $9.55 | $21.87 | $44.64 | heat pump |
| GA | 15.84¢ | $20.42 | $9.93 | $24.04 | $46.42 | heat pump |
| CO | 16.16¢ | $11.17 | $10.13 | $13.15 | $47.36 | heat pump |
| OR | 16.27¢ | $16.71 | $10.20 | $19.67 | $47.68 | heat pump |
| TX | 16.44¢ | $19.42 | $10.31 | $22.86 | $48.18 | heat pump |
| AL | 16.77¢ | $17.56 | $10.51 | $20.67 | $49.15 | heat pump |
| VA | 17.61¢ | $16.79 | $11.04 | $19.76 | $51.61 | heat pump |
| IN | 18.15¢ | $11.49 | $11.38 | $13.53 | $53.19 | heat pump |
| OH | 19.52¢ | $13.85 | $12.24 | $16.30 | $57.21 | heat pump |
| PA | 21.55¢ | $15.04 | $13.51 | $17.70 | $63.16 | heat pump |
| NJ | 23.27¢ | $14.21 | $14.59 | $16.73 | $68.20 | heat pump |
| IL | 23.85¢ | $11.25 | $14.95 | $13.24 | $69.90 | gas |
| MA | 28.82¢ | $25.06 | $18.07 | $29.50 | $84.47 | heat pump |
| NY | 29.93¢ | $17.58 | $18.76 | $20.69 | $87.72 | heat pump |
| CA | 33.25¢ | $22.01 | $20.84 | $25.91 | $97.45 | heat pump |
Gas is cheaper to run in 1 of 25 states listed: IL. Everywhere else the heat pump wins on running cost. Either way, this compares running cost only.
Where these prices come from, and what is wrong with them
Electricity. U.S. Energy Information Administration, Electric Power Monthly, Table 5.6.A — Average Price of Electricity to Ultimate Customers by End-Use Sector, by State, May 2026. Retrieved 2026-08-06.
Natural gas. U.S. Energy Information Administration, Natural Gas — Price of Natural Gas Delivered to Residential Consumers, annual by state, 2025 (latest complete annual year published). Retrieved 2026-08-06.
The price of gas used in private dwellings, including apartments, for heating, cooking, water heating, and other household uses.
What it settles here That is the whole definition, and it settles what the gas column above is and is not: it is the average price across every residential use of gas in the state — furnace, range, water heater and dryer together — collected under a tariff that includes the fixed monthly customer charge, so it is not the price of the marginal summer therm a pool heater actually burns.
Propane. U.S. Energy Information Administration, Weekly U.S. Propane Residential Price, week ending 2026-03-30. Retrieved 2026-08-06.
Use your marginal rate, not the average
The single most common error in pool energy arithmetic is using an average rate for an incremental load. Pool heating is added on top of everything else your house already uses, so the electricity it consumes is billed at whatever tier or time-of-use period it lands in — which on a tiered residential rate is usually the top one.
Find the rate that applies to the last kilowatthour on your bill, not the total divided by the usage. In some states those two numbers differ by half again, and every cost figure on this site scales linearly with the one you use.
There is a seasonal error stacked on top of the tier error, and it runs the same direction:
Prices are usually highest in the summer when total demand is high because more expensive generation sources are added to meet the increased demand.
What it settles here Pool heating is a summer load almost by definition, so it lands in the months the same agency calls the dearest, while the electricity column in the table above is May 2026 — a shoulder month — which means the published average understates a swimming season rather than overstating it, and a bill from July or August is a better input than anything on this page.
The same applies to gas. The annual state average folds in a fixed monthly customer charge you are already paying whether or not you heat the pool. Summer pool heating is close to pure commodity gas, so your marginal therm is usually cheaper than the published average.