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Furnace Repair Cost in Missouri: What Each Problem Usually Costs to Fix

A symptom-by-symptom guide to furnace repair costs in Missouri, from igniters and flame sensors to blower motors and heat exchangers, plus when to replace.

Furnace Repair Cost in Missouri: What Each Problem Usually Costs to Fix

Missouri weather is hard on furnaces. A December afternoon in Springfield can hit 60 degrees, and two days later an arctic front drops Kansas City below zero. Those swings mean furnaces cycle on and off constantly, and parts wear out faster than they would in a steadier climate.

Most furnace repairs in Missouri cost between $150 and $650. Simple fixes like a flame sensor cleaning or a new thermostat land on the low side, while blower motors, inducer motors, and control boards often run $500 to $1,200. This guide works through the problems homeowners notice first, what usually causes them, and what you can expect to pay.

How Missouri Contractors Price Repairs

The first charge on nearly every bill is the service call. In St. Louis, Kansas City, and Columbia, that diagnostic fee usually runs $80 to $150 during regular hours.

Rural service areas in the Ozarks or northern Missouri sometimes add a mileage charge on top.

Most HVAC companies here use flat rate pricing. The technician diagnoses the problem, then quotes a set price for the repair that includes parts and labor. That makes the bill easier to predict, though it also means the same repair can cost noticeably different amounts from one company to another.

Night, weekend, and holiday calls bring a premium. During a January cold snap, emergency fees of $100 to $250 are common, and the busiest companies may still need a day to reach you. Customers with a maintenance agreement usually move to the front of the line.

When the Furnace Will Not Turn On at All

A furnace that does nothing when the thermostat calls for heat is one of the most common winter calls. The fix is often cheaper than homeowners fear.

Start with the basics before you call anyone. Check that the thermostat has fresh batteries and is set to heat, that the furnace switch near the unit is on, and that the breaker has not tripped. A surprising number of service calls in Missouri end with a flipped switch or a dead battery.

Thermostat Problems

If the thermostat itself has failed, replacing it with a basic programmable model usually costs $150 to $350 installed. Smart thermostats run about $250 to $500 with installation. Ameren Missouri, Evergy, and Spire have offered rebates on qualifying smart thermostats in some years, so check before you buy.

Wiring issues between the thermostat and furnace are another possibility, especially in older St. Louis homes where thermostat wire has been spliced over the years. A technician can usually trace and repair it for $150 to $300.

Control Board Failures

The control board is the furnace's brain. When it fails, the furnace may not respond at all or may run the blower nonstop. Replacing one typically costs $400 to $900 in Missouri, depending on the brand and whether the part is in stock locally.

Power surges from summer thunderstorms are a common cause of board failures here. A whole house surge protector, installed by an electrician for about $300 to $600, can help protect the furnace and other electronics.

When the Furnace Runs but Blows Cold Air

This problem usually points to an ignition issue. The blower comes on, but the burners never light or light and shut off after a few seconds.

A dirty flame sensor is the most frequent cause. The sensor confirms the burners are lit, and a coating of residue can make it think they are not. Cleaning or replacing it often costs $100 to $250.

Hot surface igniters are next on the list, and they crack with age. Replacing one usually runs $175 to $400.

On older furnaces, a failed thermocouple or pilot assembly may be the culprit. Many homes in older parts of Kansas City, Independence, and St. Joseph still have furnaces from the 1990s or earlier, and these parts typically cost $150 to $350 to replace.

When the Furnace Makes Strange Noises

Noises tell a technician a lot. Squealing often means a worn blower belt on an older unit or a failing blower motor bearing on a newer one. Belt replacement is cheap at about $100 to $200, while a new blower motor runs $450 to $1,200.

Loud booms when the furnace starts usually mean delayed ignition. Gas builds up before the burners light, then ignites all at once. That points to dirty burners or a weak igniter, and a cleaning plus parts often costs $150 to $400.

Do not ignore it, because repeated delayed ignition can damage the heat exchanger.

Rattling or humming from the inducer motor area is another common one. Inducer motor replacement typically costs $400 to $900. If the motor is still under the manufacturer's parts warranty, you may only pay labor.

The Heat Exchanger Question

A cracked heat exchanger is the repair every homeowner dreads. The heat exchanger separates combustion gases from the air that moves through your home, and a crack can allow carbon monoxide to leak into the airflow.

Replacing a heat exchanger can cost $1,500 to $3,500 or more. On a furnace older than about 15 years, most technicians will recommend replacing the whole furnace instead. Many manufacturers offer 20 year or lifetime warranties on heat exchangers, so check your paperwork before you pay out of pocket.

Ask the technician to show you the crack, either in person or on a camera. A legitimate diagnosis should come with photos or a visual check. If you feel unsure, a second opinion for $100 or so is worth it before you spend thousands.

After an Ice Storm or Power Outage

Ice storms hit Missouri more often than many people expect, and the outages that follow can last for days in places like Joplin, Rolla, and the rural counties north of Columbia. Furnaces need electricity to run the igniter, inducer, and blower, so a gas furnace will not heat the house without power.

When the power comes back, surges can damage control boards and motors. If your furnace will not restart after an outage, reset the breaker once and wait a few minutes. If it still does nothing, call for service instead of cycling the power over and over, which can make a board problem worse.

Some homeowners in outage prone areas add a generator transfer switch so the furnace can run on a portable generator. An electrician typically charges $500 to $1,500 for that work. It is a smaller expense than a whole house generator and keeps the heat on through a multi day outage.

Repair Costs at a Glance

Here is a quick reference for common furnace repairs in Missouri. These are rough installed ranges that include parts and labor:

• Flame sensor cleaning or replacement: $100 to $250
• Hot surface igniter: $175 to $400
• Thermostat replacement: $150 to $500
• Blower motor: $450 to $1,200
• Inducer motor: $400 to $900
• Control board: $400 to $900
• Gas valve: $350 to $800
• Heat exchanger: $1,500 to $3,500

Propane furnaces in rural Missouri usually cost about the same to repair as natural gas models. The difference is fuel. If the propane tank runs empty, the supplier may need to perform a leak check before relighting the system, which can add a fee.

Repair or Replace in Missouri

Many technicians in Missouri use a simple guideline. If the furnace is older than about 15 years and the repair costs more than a third of a new system, replacement deserves a hard look. A new gas furnace here typically costs $3,500 to $7,500 installed, with high efficiency models at the upper end.

Missouri's low natural gas rates compared to many states make the efficiency payback slower than it is in the Northeast. A 96 percent furnace still saves money over an old 80 percent unit, though it may take longer to earn back the higher price. In milder southern parts of the state, a heat pump with a gas backup is an increasingly common choice.

Licensing and Hiring

Missouri does not have a statewide HVAC license. Licensing is handled locally.

Requirements in St. Louis County, Kansas City, Springfield, and Columbia are different from those in smaller towns.

Ask whether the technician holds a local mechanical license and whether the company carries liability insurance.

For gas work, many cities require a permit for major repairs or replacements. A reputable contractor will handle that for you. You can compare local options through our listings of Missouri HVAC companies near you.

Get a written estimate for any repair over a few hundred dollars. It should list the part, the labor, and any warranty. For more home cost guides from around the state, you can browse our Missouri home service articles.

Frequently Asked Questions

How much is a furnace tune-up in Missouri?

Most companies in St. Louis and Kansas City charge about $90 to $180 for a standard tune-up. Maintenance plans that include a fall furnace check and a spring AC check often run $150 to $250 a year.

Why does my furnace keep shutting off after a few minutes?

Short cycling often comes from a dirty filter, a faulty flame sensor, or an oversized furnace. A clogged filter costs a few dollars to fix, while a flame sensor cleaning usually runs $100 to $250 with the service call.

Is it safe to run my furnace if I smell gas?

No. Leave the house, then call Spire, Ameren Missouri, or your local gas or propane provider from outside. Utilities respond to gas leak reports at no charge.

How long do furnaces last in Missouri?

Most gas furnaces here last about 15 to 20 years with regular maintenance. The heavy cycling caused by Missouri's temperature swings can shorten that if the system never gets a yearly check.