Furnace Replacement Cost in Great Falls, Montana
Our 2026 estimate for furnace replacement in Great Falls, MT is $3,600 to $8,700. That puts Great Falls 12% above the national average, mainly because of lower local labor costs and the bigger heating equipment this climate calls for.
Compare Free Quotes in Great Falls
Great Falls Weather and HVAC Load
Great Falls logs 6,942 heating degree days and 421 cooling degree days in a normal year, based on the closest NOAA weather station. Heating is the bigger job here, and furnaces and heat pumps in Great Falls put in far more hours than the air conditioner. Count on roughly 143 nights below 32°F and 25 afternoons past 90°F in a typical year. Snowfall averages about 66 inches. For a 2,000 sq ft house, this climate points to a heating load somewhere near 70,000 BTU/h. Treat that as a starting number. A Manual J calculation will move it up or down based on insulation and windows.
| Heating degree days / year | 6,942 |
|---|---|
| Cooling degree days / year | 421 |
| Nights at or below 32°F | 143 |
| Days above 90°F | 25 |
| Average low / high | 35.1°F / 59°F |
Great Falls Housing Stock
Census figures put the median build year in Great Falls at 1965, so a typical house here has about 61 years on it. A lot of these homes are on their second or third system by now. The ductwork is usually original, and leaky joints are common. Great Falls has roughly 18,000 owner-occupied homes, or 68.4% of households. The median home value is $237,400, and median household income is $63,934. We use both figures to adjust labor and pricing for this page.
NOAA storm reports for Cascade County show 12 hail days and 22 days with damaging thunderstorm winds over the six years from 2020 to 2025. The largest hail reported was 3 inches across. Hail flattens the thin aluminum fins on condenser coils and cuts airflow. After a big storm, take a look at the outdoor unit; homeowners insurance often covers the damage. In Great Falls, 20% of residents are 65 or older. For older adults, a house with no heat in January or no AC during a heat wave is a medical risk. Mention it when you call, since many companies put those calls first.
When Replacement Makes Sense
- The furnace is 15 to 20 years old or more
- A repair quote runs past a third of the cost of a new unit
- A tech found a cracked heat exchanger, or the CO detector has gone off
- Gas or electric bills keep climbing even though usage hasn't changed
What Moves the Price
- BTU size, which should come from a Manual J load calculation
- Condition of the existing ductwork and any changes it needs
- New PVC venting if you move to a condensing model
- Permit and inspection fees, which the local building department sets
- AFUE rating: a basic 80% unit vs. a 96% condensing furnace
- Single-stage, two-stage or modulating gas valve
For Great Falls we raised the national figures about 12%, based on local income, home values and climate-based equipment sizing. Get at least three written quotes; real bids can land outside this range.
What the Quote Should Cover
- The permit and the manufacturer warranty registration
- Removing and hauling away the old furnace
- Gas line and vent connections
- The new furnace, filter rack and thermostat wiring
- Combustion and safety tests
Montana Permits, Efficiency Rules and Rebates
Montana falls in the DOE's North region. New split central air conditioners must meet at least 13.4 SEER2, and heat pumps sold anywhere in the U.S. need 14.3 SEER2 and 7.5 HSPF2. Equipment replacements in Great Falls generally need a mechanical permit, and a reputable contractor will pull it for you. Ask for their Montana license or registration number and a certificate of insurance with the quote. The federal 25C tax credit ended for equipment installed after December 31, 2025, so incentives now come mostly from utilities and state programs. Check your electric and gas utility's rebate page before you pick equipment.
Before You Hire
- Ask for the Manual J load calculation in writing. Oversized furnaces are the most common mistake we see.
- Replace it in early fall if you can. A no-heat emergency in January costs more and leaves you fewer choices.
- Make sure all three quotes are for the same AFUE and staging, or you can't compare them.
Get Free Furnace Replacement Quotes in Great Falls
Tell us where you are and up to three licensed local pros will get in touch. You don't have to hire any of them.
Furnace Replacement Questions from Great Falls Homeowners
How much is furnace replacement in Great Falls?
Plan on $3,600 to $8,700, with most jobs near $6,400. Equipment efficiency, house size and the condition of the ducts and wiring decide where your quote falls.
When is the best time to schedule furnace replacement in Great Falls?
Between late spring and early fall. Great Falls averages 143 freezing nights a year, and heating calls spike from November through February.
How long does a furnace replacement take?
A straight swap is usually done in one day, somewhere between 4 and 10 hours. Moving to a condensing furnace with new PVC venting can add a few more.
Is a high-efficiency furnace worth it?
In cold climates, a 95%+ AFUE furnace usually earns back the price difference in lower gas bills. Where winters are mild, the payback can take a very long time.
Furnace Replacement Near Great Falls
Sources: U.S. Census Bureau ACS 5-year estimates 2019-2023 and 2024 population estimates; NOAA NCEI U.S. Climate Normals 1991-2020, station Great Falls 16st; NOAA Storm Events Database 2020-2025, Cascade County. Prices are our estimates, not contractor quotes. Updated 2026.