Natural Gas Heating Cost Calculator
See what heating your home with natural gas costs in a winter month and over the whole season, from its size, your climate, furnace and gas price.
Your winter gas bill comes down to how much house you heat, how cold it gets, and how old the furnace is. An older furnace burns about a quarter more gas than a standard one for the same heat.
Your house
The part of the house the furnace heats; most homes are 1,200 to 2,500 sq ft.
Heated square feet
Your winters
Your furnace
If you're not sure, a furnace with white plastic vent pipes is high-efficiency.
What you pay per therm
Your bill's total divided by the therms used. The winter average is about $1.31; if your bill shows Ccf, a Ccf is about the same as a therm.
Gas heating in a winter month
About $152 a month
For 2,000 sq ft in a cold climate
This is the gas for heat only. A gas water heater, stove or dryer, and your gas company's monthly service charge, are on the bill too. January usually runs above this and March below. 2026 figures.
💡About this calculator▼
The first cold-month gas bill of the year always seems to come as a surprise. It doesn't have to. What your house costs to heat with gas comes down to a few things you know: how much space the furnace heats, how cold your winters are, how efficient the furnace is, and what you pay for gas.
This works out the bill. You get the gas heating cost for a typical winter month and for the whole heating season. If your furnace isn't a high-efficiency model, it also shows what a new one would save you each year.
Your price matters. Gas costs about twice as much in New England as in the Mountain states, so put in the price per therm from your own bill if you can.
How much gas a house like yours burns for heat. The government's survey of home energy use measured how much natural gas gas-heated homes burn for heating in each climate. Divided by those homes' heated area, that's about 34,000 BTU per square foot a year in cold climates, 27,100 in moderate ones and 14,500 in mild ones. A therm is 100,000 BTU, so a 2,000-square-foot house in a cold climate uses about 680 therms a year for heat.
Your furnace moves it up or down. The survey's homes are taken as having a typical furnace of about 80 percent efficiency. An older furnace, around 65 percent, burns about 23 percent more gas for the same heat; a high-efficiency model at 95 percent burns about 16 percent less.
A winter month. January, February and March carry about half of a year's heating between them, so a typical winter month is about 17 percent of the year's gas for heat.
Worked example. 2,000 square feet in a cold climate with a standard furnace: 2,000 × 34,000 = 68 million BTU = 680 therms a year; a winter month is 17 percent of that, 116 therms; at $1.31 a therm that's about $152 a month and about $891 for the season. A 95 percent furnace would use about 107 fewer therms, saving about $141 a year.
📐How it's calculated▼
Therms a year = square feet × gas BTU per square foot × (0.80 ÷ your furnace efficiency) ÷ 100,000.
Gas BTU per square foot: cold 34,000, moderate 27,100, mild 14,500. Furnace efficiency: high-efficiency 95%, standard 80%, older 65%.
Winter month = 17.06% of the year. Cost = therms × your price per therm.
Default (2,000 sq ft, cold, standard, $1.31): 680 therms a year, 116 in a winter month → $152 a month, $891 a season; a 95% furnace saves about $141 a year. Older furnace: 837 therms → $187 a month, $1,096 a season, and $346 a year to save.
📎Sources:U.S. Energy Information Administration — 2020 Residential Energy Consumption Survey, natural gas use by end use and climate (Table CE4.1),U.S. Energy Information Administration — Short-Term Energy Outlook, regional natural gas prices (Table 5b),U.S. Energy Information Administration — Short-Term Energy Outlook, heating degree days (Table 9c),U.S. Energy Information Administration — converting natural gas prices between Mcf, Ccf and therms
🔍Finding your inputs▼
Heated square feet: The part of the house the furnace heats, usually the living area on your listing or appraisal, not counting an unheated basement or garage.
Your winters: Cold for the Northeast, Midwest and mountain states; moderate for the Mid-Atlantic and Upper South; mild for the Deep South, Southwest and California.
Your furnace: High-efficiency if it vents through white plastic pipes; standard if it has a metal flue and no pilot light; older if it's past about 20 years or has a standing pilot light.
What you pay per therm: Take the total on a winter gas bill and divide by the therms used. If your bill shows Ccf instead, a Ccf is about 1.04 therms, close enough to use as-is. The winter national average is about $1.31.
⚠️Special situations▼
How much does it cost to heat a 2,000 sq ft house with natural gas?
In a cold climate with a standard furnace at the winter average of $1.31 a therm, about $150 a month in the heart of winter and about $890 for the season. In a moderate climate it's about $120 a month; in a mild one about $65. An older furnace adds about a quarter to those figures, and gas in New England costs nearly twice the national average.
My bill is much higher than this.
Three things usually explain it. The bill includes more than heat: a gas water heater alone uses a meaningful share of a winter bill, and the monthly service charge is there even when you use nothing. Your price may be higher than the default, so use the total divided by the therms on your own bill. And an older or leaky house, or ducts in an unheated attic, can burn well above the average.
Is a new high-efficiency furnace worth it?
For heating cost alone, it depends on how much you burn. Going from an older 65 percent furnace to a 95 percent one cuts the gas for heat by almost a third, about $350 a year for a 2,000-square-foot house in a cold climate. From a standard 80 percent furnace the saving is closer to $140 a year, which takes a long time to repay a new furnace, so the upgrade usually makes the most sense when the old one needs replacing anyway.
Therms, Ccf, Mcf: which is my bill in?
A therm is 100,000 BTU of heat. A Ccf is 100 cubic feet of gas, which holds about 1.04 therms, so the two are nearly interchangeable. An Mcf is 1,000 cubic feet, about 10.4 therms. If your bill lists Ccf, divide the total by the Ccf and use that as your price per therm; the difference is under 4 percent.
❓Common questions▼
How much does natural gas heating cost per month?
For a typical 2,000-square-foot house, about $150 a month in a cold climate, $120 in a moderate one and $65 in a mild one during the heart of winter, at the winter national average of about $1.31 a therm and a standard furnace. That's the gas for heat alone; water heating and the monthly service charge come on top.
How many therms does a house use in winter?
A gas-heated home in a cold climate burns about 34,000 BTU of gas per square foot a year for heat, so about 680 therms for 2,000 square feet, and about 116 therms in a typical winter month. In a moderate climate that's about 540 therms a year; in a mild one about 290.
How much can a high-efficiency furnace save?
Compared with a standard 80 percent furnace, a 95 percent model uses about 16 percent less gas for the same heat; compared with an older 65 percent furnace, about 32 percent less. For a 2,000-square-foot house in a cold climate at $1.31 a therm, that's about $140 or $350 a year.
What is AFUE?
Annual fuel utilization efficiency, the share of the gas a furnace turns into heat for the house over a typical year. A 95 percent AFUE furnace sends 95 percent into the house and 5 percent up the vent. Older furnaces run about 56 to 70 percent, standard ones about 80 to 83 percent, and high-efficiency condensing furnaces 90 to 98.5 percent.
Why does gas cost so much more in some states?
Delivery. The gas itself is the smaller part of a home's price: this winter's wholesale forecast is about $3.25 per thousand cubic feet against about $14 at the house. The rest is pipelines and local distribution, which cost much more in some regions. This winter's forecast puts New England at about $23 per thousand cubic feet, around $2.29 a therm, against about $10.60 in the Mountain states, around $1.02.
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