Furnace repair costs $150 to $900 for most common problems, with the average repair landing at $350 to $500. The least expensive repairs — a thermocouple, a flame sensor cleaning, a limit switch — cost $150 to $300. The most expensive repairs that are still worth making — a blower motor, an inducer fan, a control board — cost $500 to $1,200. A repair that exceeds $1,500 typically involves the heat exchanger or the gas valve, and at that price point, the repair-versus-replace calculation tilts toward replacement, especially if the furnace is more than 15 years old.
The first cost in any furnace repair is the diagnostic visit. Most HVAC companies charge a service call fee of $75 to $150 to send a technician to the house, diagnose the problem, and provide a repair estimate. Some companies waive the diagnostic fee if you approve the repair. Others do not. Ask when you schedule the appointment. The diagnostic fee is the cost of knowing what is wrong. The repair cost is the cost of fixing it. Together, a $100 diagnostic fee and a $400 repair are a $500 furnace repair.
Furnace Repair Costs by Type of Repair
| Repair | Part Cost | Total Cost (Parts + Labor) | Typical Labor Time |
| Thermocouple replacement | $10-$20 | $150-$250 | 30-45 min |
| Flame sensor cleaning | $0 (cleaning only) | $100-$200 | 15-30 min |
| Flame sensor replacement | $20-$40 | $150-$300 | 20-30 min |
| Hot surface igniter | $30-$80 | $200-$400 | 30-60 min |
| Limit switch | $15-$40 | $150-$300 | 30-45 min |
| Pressure switch | $30-$60 | $200-$350 | 30-60 min |
| Gas valve | $200-$500 | $500-$1,000 | 1-2 hours |
| Inducer fan motor | $150-$400 | $400-$800 | 1-1.5 hours |
| Blower motor (PSC) | $150-$350 | $400-$700 | 1-1.5 hours |
| Blower motor (ECM) | $400-$900 | $800-$1,500 | 1-2 hours |
| Control board | $150-$400 | $400-$800 | 30-60 min |
| Heat exchanger (under warranty) | $0 (part covered) | $500-$1,000 (labor only) | 4-8 hours |
| Heat exchanger (out of warranty) | $500-$1,500 | $1,500-$3,500 | 4-8 hours |
The parts themselves are surprisingly inexpensive. A $20 thermocouple, a $40 flame sensor, or an $80 igniter costs less than a tank of gas. The cost of a furnace repair is overwhelmingly labor — the technician’s time, the truck, the insurance, the training, and the fact that the technician drove to your house instead of working on a $15,000 furnace replacement. The $200 flame sensor replacement is $40 for the part and $160 for the hour of labor, the drive time, and the diagnostic expertise to identify the flame sensor as the failed component.
Emergency vs. Scheduled Repair: Timing Changes the Price
A furnace repair scheduled for a weekday during business hours costs the standard rates in the table above. The same repair at 9 PM on a Saturday night in January costs 50% to 100% more. The emergency surcharge covers the technician’s overtime pay, the hazard of diagnosing a furnace in a freezing house, and the market reality that a homeowner with no heat on a sub-zero night will pay whatever it costs to get the heat back on.
A flame sensor cleaning that costs $150 on a Tuesday morning costs $300 at midnight on a Saturday. A blower motor replacement that costs $600 during a scheduled appointment costs $900 to $1,200 as an emergency call. The emergency surcharge is unavoidable when the furnace fails on a cold night, but if the furnace has been intermittently acting up for weeks — a flame that goes out occasionally, a blower that makes noise — fixing it during business hours before it fails completely saves $200 to $500.
Emergency vs. scheduled cost examples: Thermocouple: $175 scheduled / $300 emergency. Hot surface igniter: $300 scheduled / $500 emergency. Blower motor: $550 scheduled / $900 emergency. The surcharge is highest on weekends, holidays, and overnight calls. A furnace that acts up on a Wednesday and is repaired on Thursday costs half of what it costs when it is ignored until it fails on a Saturday night.
Gas vs. Oil vs. Electric Furnace Repair Costs
| Furnace Type | Typical Repair Range | Most Expensive Common Repair | Annual Maintenance Cost |
| Natural gas | $150-$900 | ECM blower motor ($800-$1,500) | $100-$200 (tune-up) |
| Oil | $200-$1,200 | Fuel pump + nozzle + cad cell ($500-$900) | $150-$250 (tune-up + nozzle) |
| Electric | $150-$800 | Heating element + sequencer ($400-$700) | $75-$150 (inspection) |
Oil furnace repairs cost more than gas furnace repairs because oil burners are more mechanically complex, fewer technicians are trained to service them, and oil-specific parts — fuel pumps, nozzles, ignition transformers — are more expensive than their gas furnace equivalents. Electric furnace repairs cost less than both because an electric furnace has no combustion system: no burners, no gas valve, no heat exchanger, no flue. The heating elements and the sequencer relays are the only parts that fail.
When to Repair vs. Replace a Furnace
| Scenario | Action | Reasoning |
| Repair < $500, furnace < 10 years old | Repair | Furnace has 10+ years of life; repair is a fraction of replacement cost |
| Repair < $500, furnace 10-15 years old | Repair | Furnace has 5-10 years left; repair is cost-effective |
| Repair $500-$1,000, furnace 15+ years old | Get quotes for both | Repair cost approaches 15-25% of replacement; do the math |
| Repair > $1,000, furnace 15+ years old | Replace | Repair exceeds 25% of replacement cost and furnace is near end of life |
| Cracked heat exchanger, any age | Replace (unless under warranty) | Heat exchanger replacement under warranty costs $500-$1,000 labor; out of warranty costs $1,500-$3,500 |
The financial threshold for repair vs. replacement is roughly $1,000 on a furnace over 15 years old. Spending $800 to repair a 16-year-old furnace that will likely need another $500 repair within two years is throwing money at a dying appliance. A $5,000 replacement furnace spread over 20 years costs $250 per year. An $800 repair on a furnace that lasts two more years costs $400 per year — more than the annualized cost of a new furnace. The replacement is the better financial decision even though the upfront cost is higher.
How Warranty Affects Repair Costs
Every furnace comes with a manufacturer’s warranty that covers the cost of defective parts for a specified period. The standard warranty on most residential gas furnaces is: 10 years on parts, 20 years to lifetime on the heat exchanger. The warranty covers the part, not the labor to install it. A heat exchanger replacement under warranty still costs $500 to $1,000 in labor. A control board replacement under warranty costs $150 to $300 in labor for the part that would have cost $400 to $800 if the part were not covered.
The warranty is tied to the original purchaser. If you bought a house with a furnace that was installed by the previous owner, the warranty may not have transferred. Some manufacturers — Carrier, Trane, Lennox — reduce the parts warranty from 10 years to 5 years for subsequent owners. Check the warranty status with the manufacturer before approving a repair. The furnace’s serial number, located on the rating plate inside the front panel, is all you need to check warranty coverage on the manufacturer’s website or by phone.
Understanding the Diagnostic Fee and Repair Estimate
The diagnostic fee — also called a service call fee or a trip charge — is $75 to $150 and covers the technician’s time to drive to your house, diagnose the problem, and provide a written estimate for the repair. The fee is not a deposit toward the repair. It is payment for the diagnosis, regardless of whether you approve the repair. Some companies apply the diagnostic fee toward the repair cost if you approve the work. Ask when scheduling.
When the technician provides the estimate, it should include: the specific part that has failed, the part cost, the labor hours, the labor rate, and the total. A vague estimate — “your furnace needs a repair, it will be $500” — without specifying which part is being replaced is not acceptable. Ask: “Which part has failed? What is the part number? How many hours of labor?” A reputable technician answers these questions without hesitation. A technician who cannot or will not specify the failed part is selling a repair they have not diagnosed.
FAQ: Common Questions About Furnace Repair Costs
Is an annual furnace tune-up worth the cost?
Yes, for gas and oil furnaces. A $100 to $200 annual tune-up catches a failing thermocouple, a dirty flame sensor, or a cracked heat exchanger before it becomes a $500 emergency repair on a cold night. The tune-up pays for itself if it prevents one emergency service call. Oil furnaces in particular require annual tune-ups — the nozzle must be replaced, the electrodes adjusted, and the combustion efficiency tested with instruments that measure smoke, draft, and CO2. Skipping an oil furnace tune-up guarantees a clogged nozzle and a no-heat call within 18 to 24 months.
What is the cheapest furnace to repair for a rental property?
A single-stage 80% AFUE natural gas furnace with a standard PSC blower motor. The parts are universally available, every HVAC technician knows how to repair it, and the most expensive common repair — a PSC blower motor — costs $400 to $550. High-efficiency condensing furnaces with ECM blower motors, modulating gas valves, and communicating control boards cost two to three times as much to repair, and the proprietary parts must be ordered from the manufacturer rather than picked up at the local HVAC supply house. For a rental property where repair cost matters more than efficiency, an 80% single-stage furnace is the correct choice.
The Diagnostic Fee Buys Certainty; the Repair Buys Heat
A furnace repair costs $150 to $900 for most common problems, with the median around $400. The $100 service call fee tells you what is wrong. The $300 to $500 repair fixes it. Together, a $500 furnace repair is one of the most common expenses in homeownership and one of the few where spending the money immediately — during business hours, before the furnace fails completely — saves $200 to $500 over the emergency version of the same repair.
When the technician hands you the estimate, ask three questions: what part failed, what does the part cost, and how many hours of labor. Multiply the labor hours by the company’s hourly rate and add the part cost to verify the total. If the repair exceeds $1,000 and the furnace is over 15 years old, ask for a replacement quote as well. The technician is already at your house. The second quote takes 15 minutes and tells you whether repairing or replacing is the better financial decision.
