Furnace Installation in Lewistown, MT
A new furnace here will run from September through June every year. Tell us about the house, and a licensed contractor who covers Fergus County will get in touch.
Tell us about the job
It takes about a minute.
Ten months of heat, out of a furnace that has to earn it
Lewistown asks for heat from September through June. That's ten months a year the furnace runs, with winter nights averaging 14°F. A furnace here isn't idling most of the year and working hard for a few weeks. It's working most of the year.
Any new gas furnace installed today has to hit at least 80 percent AFUE, so that part isn't a choice. What matters more in Fergus County is what happens when a storm takes the power out. The state saw households go a full day or more without power in 2024, and this area has logged 28 winter storms and 147 damaging wind events over the past ten years. A furnace installed here needs to be sized and set up for a season that runs long and doesn't always cooperate.
- 10 months
- September through June, your furnace is on duty
- 14°F
- the average winter night it heats against
- 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 Fergus County compared with a gas furnace.
Estimates for a typical Fergus 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.
Montana's Department of Labor and Industry tests and records HVAC contractors before they can be licensed. That license belongs to the contractor, not to any single job, so it carries over from one furnace install to the next. Work under $2,500 does not need a licensed contractor, but a furnace installation runs well past that.
The license covers who is allowed to do the work. It does not replace the permit and inspection a furnace installation still needs from the local building office in most cities and counties, where someone checks the finished work once it's done. In Fergus County, 47% of homes heat with gas.
Source: Montana Legislature
- What size furnace does my house need?
- The right size comes from a load calculation, not the square footage of your house alone. A contractor measures your insulation, your windows, your ceiling height, and how the place holds heat through a winter where nights average 14°F. A furnace that's too big cycles on and off and wears out early. One that's too small runs constantly and still can't keep up. Ask whoever quotes the job to walk you through the calculation, not just hand you a number.
- How do I know it's time to replace my furnace?
- Watch for uneven heat, a furnace that runs longer than it used to, or repairs that keep coming back. Homes here need heat from September through June, so a furnace that's struggling gets tested for ten months of the year, not just a few weeks in deep winter. Age matters too. If yours is old enough that parts are getting hard to find, or a contractor tells you the repair costs more than a new unit would, that's the point to plan a replacement instead of another fix. Waiting until it fails on a 14°F night gives you no time to choose carefully.
- Is a high-efficiency furnace worth it?
- It depends on how much you run your furnace and what you're paying to run it now. Since 2015, every new non-weatherized gas furnace has to hit at least 80 percent AFUE, so even a standard replacement today burns less fuel than an old one. A high-efficiency model goes further, and that difference matters more in a place that needs heat ten months a year than somewhere with a short winter. A contractor can look at your current unit and your house and tell you whether the jump in efficiency is worth the difference in equipment for your situation.