Furnace Installation in St. Louis, MO
A new furnace here will run from October through April every year. Tell us about the house, and a licensed contractor who covers St. Louis will get in touch.
Tell us about the job
It takes about a minute.
Seven months of heat, and winters that test the grid
St. Louis asks a furnace to run from October through April, seven months a year. Winter nights average 26°F, and most homes here heat with gas. A new furnace has to hold up through that whole stretch, not just the coldest week.
The area has seen 9 winter storms and 28 damaging wind events over the past ten years, and in 2024, 19 percent of Missouri households went at least 24 hours without power. A furnace installed today needs to handle both the season and the storms that come with it. It also has to meet the federal minimum for new gas furnaces, 80 percent AFUE, so it isn't wasting the fuel it burns to keep the house warm.
- 7 months
- October through April, your furnace is on duty
- 26°F
- the average winter night it heats against
- 67%
- 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 $160 a year to run in St. Louis compared with a gas furnace.
Estimates for a typical St. Louis home, from EIA household energy data, Missouri fuel prices and NOAA climate normals. Your home will differ.
- What size furnace does my house need?
- The right size comes from a load calculation, not the square footage of your house. A contractor measures your walls, windows, insulation, and ceiling height, then works out how much heat your house loses on a cold night to size the furnace to match. Too big and it short cycles, heating the air fast and shutting off before the house feels warm. Too small and it runs constantly and still can't keep up. With winter nights here averaging 26°F, getting this number right matters more than it would somewhere milder.
- How do I know it's time to replace my furnace?
- Age is the first thing to look at. An older furnace that needs a repair tech out more than once in the same season for the same problem is telling you something. Watch also for uneven heat between rooms, a furnace that runs longer than it used to, or a gas bill that climbs without a reason. Houses here need heat from October through April, so a furnace that's struggling won't get much of a break to prove itself.
- Is a high-efficiency furnace worth it?
- It depends on how much you heat your home and what furnace you have now. Every new non-weatherized gas furnace sold today has to reach at least 80 percent AFUE, but high-efficiency models go higher, meaning less of the gas you burn is lost up the vent. With about two thirds of homes in the county heating with gas and a heating season that runs October through April, the fuel savings have more months to add up than they would in a place with a short winter. A contractor can walk through the actual models and pricing for your house.