Furnace Repair St. Louis: $133 to $505 + City Permits (2026)

We found no published St. Louis furnace repair price, so the repair rows are national figures. The permit row is local.

Do this now: furnace out in St. Louis

1. Gas smell or a CO alarm: get everyone out, then call 911 or Spire from outside. CPSC says do not search for the source.
2. Thermostat on heat and above room temperature, fan on AUTO (Carrier); furnace switch on; breaker set. If a breaker trips again, stop resetting it (Bryant).
3. Check the filter; Bryant says a dirty one can trip the high-limit switch.
4. Protect the pipes: open sink cabinets and drip cold water from faucets on outside walls (Red Cross). See frozen pipes.
5. Never heat with the oven or stove, and keep space heaters 3 feet from anything that burns (CDC).

Is it an emergency? St. Louis freeze days

A furnace failure is an emergency in St. Louis when it freezes, and Lambert airport averages 84.9 days a year with a low at or below 32 F, NOAA's 1991 to 2020 normals show. Call now for no heat in a freeze, a gas smell, a CO alarm or a furnace that will not stay lit. A furnace that still heats with a new noise can wait for a weekday, when labor costs less. If an alarm is going off, follow carbon monoxide alarm going off; for vents blowing cool air, see furnace blowing cold air.

St. Louis has the oldest housing of the 33 cities we cover

The Census Bureau's 2020 to 2024 survey puts the City of St. Louis's median year built at 1939 or earlier, the oldest of the 33 cities we track and far older than the U.S. median of 1980. Of the city's 174,111 housing units, 100,811 were built in 1939 or earlier and 150,086 before 1980.

HomeGuide says most technicians replace a cracked heat exchanger rather than repair it because of the carbon monoxide risk, and CPSC asks for a professional inspection of fuel-burning heating systems every year. HomeAdvisor puts furnace life at 15 to 30 years; see how long a furnace lasts and furnace replacement cost.

St. Louis furnace permits and city-licensed contractors

The City of St. Louis requires a mechanical permit to install a furnace, and it issues those permits only to City-licensed mechanical contractors. The application fee is $25 per permit, plus a separate fee schedule. The city's Mechanical Contractors Board licenses mechanical contractors and pipefitters. There is no public contractor search on the board pages, so call the Building Division at (314) 622-3313 to confirm a license, or look up past permits at your address with the city's permit search.

Help with furnace repair costs in St. Louis

• Senior Minor Home Repair Program (St. Louis Area Agency on Aging): heating and cooling repairs plus basic plumbing and electrical for City homeowners 60 or older. Clients may pay part of the cost. (314) 612-5918.
• Healthy Home Repair Program (Community Development Administration, with Mission: St. Louis): health and safety repairs for owner-occupants of at least 2 years at or below 80% of area median income. Expect a significant waitlist. Hotline 314-657-3888.
• LIHEAP and ECIP (Missouri energy assistance): in the City, apply through the Urban League of Metropolitan St. Louis, (314) 615-3632. The Urban League also runs weatherization for City residents, 314-615-3600.

Ameren programs if you replace

Ameren Missouri's HVAC PAYS program offers rebates on high-efficiency HVAC and lets you repay the rest on your electric bill at 3% interest, with no credit check. Its Peak Time Savings thermostat program pays a $50 enrollment bonus plus $25 a year, but it requires a central furnace or central AC. No federal credit applies in 2026, the IRS says.

Local heating rules, programs and climate for St. Louis, from official city, county, state, utility, Census and NOAA pages.

Questions to ask a St. Louis furnace company

1. Are you licensed by the City of St. Louis Mechanical Contractors Board, and what is the license number?
2. If the furnace is replaced, will you pull the mechanical permit?
3. What is your diagnostic or trip fee?
4. Will you check the flue and heat exchanger while you are here?
5. Can I see proof of insurance and a written price before work starts?

More St. Louis heating guides

All heating and cooling: HVAC repair in St. Louis. Frozen pipes and sewer laterals: plumber in St. Louis. Compare furnace repair in Indianapolis and furnace repair in Nashville. National prices: furnace repair. Calls go to an independent company that serves your area and takes this kind of job (how calls work).