Furnace Installation in Great Falls, MT
A new furnace here will run from September through June every year. Tell us about the house, and a licensed contractor who covers Cascade County will get in touch.
Tell us about the job
It takes about a minute.
Ten months of heat, and nights that drop to 16°F
A furnace here works almost year round. Homes in Great Falls need heat from September through June, ten months out of the year, and winter nights average 16°F from December through February. That is a long season with a lot of cold nights in the middle of it.
Most homes here heat with gas, and any non-weatherized gas furnace built since November 2015 has to reach at least 80 percent AFUE under federal rule. Storms are part of the picture too. Cascade County has logged 32 winter storms and 134 damaging wind events over the past ten years, and across Montana, 18 percent of households went at least 24 hours without power in 2024. A furnace installed here needs to handle the cold and come back on its own once the power does.
- 10 months
- September through June, your furnace is on duty
- 16°F
- the average winter night it heats against
- 72%
- of homes here heat with gas, so most furnaces here burn gas
- 80% AFUE
- the federal minimum any new unit must meet
NOAA nClimDiv, 1991–2020 normals
A high-efficiency gas furnace would save about $80 a year to run in Cascade County compared with a gas furnace.
Estimates for a typical Cascade County home, from EIA household energy data, Montana fuel prices and NOAA climate normals. Your home will differ.
Montana requires HVAC contractors to hold a state license.
The license comes from the Montana Department of Labor and Industry. It is tied to the contractor, not to any single job. The state has tested and recorded the person or company, and that record stands behind every job they take on. Montana does set one exception. Work under $2,500 does not require a licensed contractor. A furnace installation runs well above that line, so the license applies here.
That license is what stands behind this job, but it is not the only check. In most cities and counties, a furnace replacement needs a permit from the local building office, along with an inspection once the work is done. That inspection is separate from licensing and catches problems the license alone does not. It matters here because a furnace runs on gas, and a bad connection is the dangerous part of the job. Most homes in Cascade County heat with gas.
Source: Montana Legislature
- What size furnace does my house need?
- A contractor sizes it with a heat loss calculation, not just the square footage of your house. That calculation looks at your insulation, window area, ceiling height, and how much air leaks in and out, because two houses the same size can need very different furnaces. With winter lows here averaging 16°F, undersizing leaves you cold on the coldest nights, and oversizing makes the furnace cycle on and off more than it should. A furnace installer works this out as part of any installation quote.
- How do I know it's time to replace my furnace?
- Look at how often it needs a repair call, not just its age. A furnace that's starting to need a repair every year is usually a candidate for replacement rather than another fix. Uneven heat between rooms, a furnace that runs longer than it used to, or a jump in gas bills without a change in weather are also signs the heat exchanger or other core parts are wearing out. Homes here need heat from September through June, so a furnace that's struggling has a lot of months ahead of it to fail.
- Is a high-efficiency furnace worth it?
- It depends on how many months a year your furnace runs, and here that's ten, September through June. Any furnace made since November 2015 has to hit at least 80 percent AFUE, so the real question is whether to go above that minimum. A furnace that burns less gas to make the same heat matters more in a place that heats most of the year than somewhere with a short winter. A contractor can walk through the options for your house, since higher-efficiency furnaces vent differently than standard ones.