Furnace Installation in Helena, MT
A new furnace here will run from September through June every year. Tell us about the house, and a licensed contractor who covers Lewis and Clark County will get in touch.
Tell us about the job
It takes about a minute.
Ten months of heat, and winters that don't let up
A furnace in Helena works most of the year. Homes here need heat from September through June, and on winter nights the average low is 15°F. That is a long season and a hard one, and the new furnace you put in has to hold up through both.
56.6 percent of homes in the area heat with gas, and any new gas furnace made today has to reach at least 80 percent AFUE. That is the federal floor, not a feature, so it is worth asking what efficiency the unit you are getting actually hits. The area has also seen 77 winter storms and 151 damaging wind events over the past ten years, and in 2024, 18 percent of Montana households went at least 24 hours without power. A furnace that comes back on by itself when the power returns matters here.
- 10 months
- September through June, your furnace is on duty
- 15°F
- the average winter night it heats against
- 57%
- 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 Lewis and Clark County compared with a gas furnace.
Estimates for a typical Lewis and Clark 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 licenses HVAC contractors through the Department of Labor and Industry. That license is held by the contractor, not issued job by job, so it covers whoever they send out on any project, not just this furnace. Work under $2,500 does not need a licensed contractor, but a furnace installation runs well past that line, so the contractor doing this job is expected to hold that license.
The license means the state has tested and recorded this contractor. It does not mean anyone checks the furnace once it is in. That check comes from the local building office. Most cities and counties require a permit for a furnace replacement and an inspection when the work is finished, and that inspection is what catches a bad gas connection, the part of this job that can actually hurt someone. In Lewis and Clark County, 56.6% of homes heat with gas, so that permit and inspection step matters here.
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. A contractor works through your insulation, your windows, your ceiling height, and how much air leaks in and out, then matches that to a furnace output. A furnace that's too big cycles on and off fast and wears out sooner. One that's too small runs constantly and still can't keep up when it's 15°F outside. Homes here need heat ten months a year, so getting this right matters more than it would somewhere milder.
- How do I know it's time to replace my furnace?
- Watch for rising repair calls, uneven heat between rooms, and a furnace that runs longer to reach the same temperature it used to hit easily. Age matters too. A furnace installed before November 2015 may be running well under the 80 percent AFUE that's now the minimum, so it's burning more gas for the same heat. If yours is old and starting to need attention every winter, replacing it before it fails on a 15°F night is worth planning for ahead of time rather than deciding in an emergency.
- Is a high-efficiency furnace worth it?
- It depends on how much you run your furnace and what you're replacing. Homes here need heat from September through June, so a furnace here runs far more hours a year than one in a milder climate, and that changes the math on efficiency. A furnace built new today already has to hit 80 percent AFUE at minimum, and higher-efficiency models go well past that. A contractor can walk through the actual models and what each one means for your house, since the right choice depends on your furnace's current condition and how your home is set up.