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Annual Heating and Cooling Cost Calculator

Estimate what it costs to heat and cool a home for a year — and per month on average — from the heat it needs, the cooling hours, the equipment’s ratings and your energy prices.

Method reviewed October 25, 2026. Version 1.0.0. How it works

Your inputs

Unit system

Million BTU (MMBtu) per year. From last winter’s gas bills: therms × AFUE ÷ 10.

US residential average: 18.31¢/kWh (EIA, July 2026).

Include cooling?

Equivalent hours at full capacity. Roughly 600 in cool climates to 2,500+ in hot ones.

Result

Total per year
$1,159
Average per month
$97

About $1,159 a year ($97 a month on average): $606 heating, $553 cooling.

  • Fixed monthly charges on your utility bills are not included, only the per-unit energy price.
Heating per year
$606
Cooling per year
$553
Heating cost per million BTU delivered
15.16$/MMBtu
Cooling electricity
3,021kWh
Show the working
  1. Natural gas furnace or boiler: price ÷ (energy content × AFUE) × 10⁶
    $15.16 per MMBtu delivered
  2. Heating cost = cost per MMBtu × annual heat need
    $15.16 × 40 = $606
  3. Cooling energy = capacity × full-load hours ÷ SEER2 ÷ 1,000
    36,000 × 1,200 ÷ 14.3 ÷ 1,000 = 3,021 kWh → $553

How the yearly cost is worked out

Heating: the heat the home needs in a year (in millions of BTU) is divided by the system’s seasonal efficiency and multiplied by the price of the fuel. Furnaces and boilers use AFUE; heat pumps use HSPF2; electric resistance heat delivers every BTU it uses.

Cooling: the air conditioner’s capacity × the equivalent full-load hours in a season ÷ SEER2 gives the electricity it uses, which is multiplied by your electricity price.

Where to get the inputs

  • Annual heat need: a year of heating bills is the most reliable source. Therms of gas used × 0.1 × AFUE gives the delivered heat in MMBtu.
  • Full-load cooling hours: far fewer in cool northern climates than in the hot South, where they can be several times higher. Local utility efficiency programs often publish a figure for your area; the default is a mid-range value to replace.
  • Prices: defaults are recent U.S. residential averages from the EIA. Use the rates on your own bills.

Worked example

These are the example values the calculator opens with, and the result the engine calculates for them.

Inputs

Heating system
Natural gas furnace or boiler
Annual heat needed (delivered)
40
Natural gas price
1.44 $/therm
Furnace or boiler AFUE
95 %
Electricity price
0.183 $/kWh
Include cooling?
Yes
Cooling capacity
36,000 BTU/h
SEER2 rating
14.3
Full-load cooling hours per year
1,200 h

Result

Total per year
$1,159
Average per month
$97
Heating per year
$606
Cooling per year
$553
Heating cost per million BTU delivered
15.16 $/MMBtu
Cooling electricity
3,021 kWh

About $1,159 a year ($97 a month on average): $606 heating, $553 cooling.

Assumptions

  • Heating: delivered heat ÷ seasonal efficiency (AFUE, or HSPF2 for heat pumps) × energy price, using EIA energy contents.
  • Cooling: capacity × equivalent full-load hours ÷ SEER2 gives the season’s electricity.

Limitations

  • Seasonal ratings are standard-test values; real efficiency depends on installation, ducts and weather.
  • Full-load hours are the largest uncertainty in the cooling estimate.

Frequently asked questions

Why is my real bill different?

Bills include fixed monthly charges, taxes, water heating, cooking and other appliances. Rated efficiencies come from standard tests and real systems vary. Thermostat habits and weather change from year to year.

What are equivalent full-load hours?

The number of hours the air conditioner would have to run at full capacity to use the season’s electricity. Real systems cycle and run at part load, so this is a convenient measure, not the clock hours it runs.

How do I compare a heat pump with my furnace?

Run the calculator twice with the same annual heat need: once with your furnace and gas price, once with the heat pump’s HSPF2 and your electricity price. The Heating Cost Calculator also compares fuels side by side per million BTU.

Sources

  1. Energy explained — British thermal units (Btu) — U.S. Energy Information Administration. 100,000 Btu per therm; 1,036 Btu/ft³ natural gas; 91,452 Btu/gal propane; 138,500 Btu/gal heating oil; 3,412 Btu/kWh.
  2. Electric Power Monthly, Table 5.6.A — average price to ultimate customers — U.S. Energy Information Administration. U.S. residential electricity price, 18.31 ¢/kWh in July 2026.
  3. U.S. Price of Natural Gas Delivered to Residential Consumers — U.S. Energy Information Administration. Monthly U.S. residential natural gas prices ($/Mcf).
  4. What is AFUE? — Carrier. AFUE is the share of fuel energy delivered as heat over a season.
  5. 2023 Central Air Conditioner Standards — FAQ — U.S. DOE, Office of Energy Efficiency & Renewable Energy. Regional SEER2 / EER2 / HSPF2 minimum efficiencies effective 2023.

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