Furnace Repair Cost Calculator
Get an instant free estimate for furnace repair based on the repair type, fuel type, complexity, and service timing — fixing common furnace problems like a failed igniter, flame sensor, blower motor, control board, or heat exchanger to restore your heat.
Free Furnace Repair Cost Calculator
Use this calculator to calculate the cost of furnace repair near you for free. Enter your ZIP code for a localized estimate.
Number of Repairs
Enter how many repairs are needed. Most service calls address a single issue; pick the main repair type below.
Repair Type:
Fuel Type:
Complexity:
Service Timing:
Additional Services:
Estimates are instant and require no contact information.
Based on inputs, your Furnace Repair project cost is approximately:
Note that the cost above is purely an estimate.
The actual cost may be higher or lower depending on the contractor's quote.
How Much Does Furnace Repair Cost?
Furnace repair runs $150 to $700, with most repairs around $300. A cheap fix like an igniter, flame sensor, or thermostat is at the low end; a heat exchanger runs $1,000 to $2,000+. A diagnostic fee of $75 to $150 is common (often waived with the repair), and small jobs hit a minimum of about $120.
The repair type (failed part) is the biggest lever, then fuel type, complexity/age, and service timing (after-hours and emergency carry premiums) scale it. Add-ons like a tune-up, CO test, and diagnostic fee stack on top. Use the calculator above to localize the estimate, then read on for what drives your quote — and whether to repair or replace.
Furnace Repair Cost by Component & Modifier
Cost by Repair (Component)
| Repair | Typical Cost | Notes |
|---|---|---|
| Thermostat | $150 – $350 | Often a quick swap. |
| Igniter / Flame Sensor | $150 – $400 | Most common no-heat fix. |
| Blower Motor / Capacitor | $300 – $700 | Airflow / fan issues. |
| Control Board / Gas Valve | $400 – $900 | Electronic / gas control. |
| Heat Exchanger | $1,000 – $2,000+ | Major & safety-critical; consider replacing. |
Source: Baseline labor derived from U.S. Bureau of Labor Statistics, HVAC Mechanics & Installers (SOC 49-9021); ranges reflect our aggregated contractor quote data across U.S. markets for a gas furnace at standard timing.
Fuel, Complexity, Timing & Add-On Modifiers
| Modifier | Adjustment | Why |
|---|---|---|
| Electric / Propane / Oil Fuel | −10% / +5% / +20% | Simpler vs. more complex to service. |
| Minor Fix / Old-Unit Complexity | −15% / +25% | Quick fix vs. hard-to-find parts. |
| After-Hours / Emergency | +$120 / +$200 | Off-hours vs. same-day response. |
| Diagnostic / Tune-Up | +$90 / +$120 flat | Find the cause; prevent future issues. |
| Duct Cleaning / CO Test | +$180 / +$60 flat | Airflow; carbon-monoxide safety check. |
| Filter Replace / Warranty | +$30 / +$80 flat | New filter; coverage on the repair. |
Source: U.S. Bureau of Labor Statistics, HVAC Mechanics & Installers (SOC 49-9021) for baseline labor, combined with our aggregated quote ranges from HVAC repair companies; carbon-monoxide guidance per the U.S. CPSC. A minimum job charge (~$120) applies. Regional adjustments applied via the calculator above.
The 6 Factors That Drive Your Quote
1. Repair Type / Component
The main cost driver — which part failed. A thermostat (~$200) or an igniter/flame sensor (~$250) is cheap and the most common no-heat fix; a blower motor or capacitor (~$450) is mid-range; a control board or gas valve (~$650) is higher; and a heat exchanger (~$1,500) is the most, a major safety-critical repair that often signals it's time to replace the furnace. A technician diagnoses which component is at fault.
2. Fuel Type
How complex the furnace is to service. An electric furnace is simplest (about 10% cheaper) with no combustion; natural gas is the baseline and most common; propane is similar (about 5% more); and an oil furnace is the most complex (about 20% more) with its combustion system and fewer specialist technicians. The same part can cost differently by fuel because of the surrounding system.
3. Complexity & Age
How hard the specific repair is. A minor, quick fix is cheaper (about 15% less). A standard repair is the baseline. An old furnace with hard-to-find or discontinued parts adds about 25% for the harder sourcing and labor. Older units are also more likely to have multiple issues, so complexity often correlates with age — and with whether repair still makes sense versus replacement.
4. Service Timing
When you need the technician. Standard business hours is the baseline. An after-hours or weekend call adds about $120 for off-hours labor, and an emergency, same-day, or holiday visit adds about $200 for immediate response. Furnaces tend to fail on the coldest nights — if it's safe to wait until morning, standard timing saves the premium; if it's dangerously cold or you smell gas, don't.
5. Number of Repairs & Diagnostic
Most service calls address a single issue, but sometimes a technician finds more than one problem. Each repair adds its part-and-labor cost, though they share the trip. A service-call/diagnostic fee (~$90) covers finding the cause — often waived if you proceed with the repair. A proper diagnosis avoids throwing parts at the wrong problem, so it's worth the fee even when it isn't credited.
6. Tune-Up, Safety & Extras
Several add-ons round out a service visit: a full tune-up/maintenance (~$120) to prevent future breakdowns, duct cleaning (~$180) for airflow, a carbon-monoxide test (~$60) for safety on combustion furnaces, a filter replacement (~$30), and a repair warranty (~$80). A tune-up and CO test in particular are worth bundling with a repair, since the technician is already there.
Repair or Replace? The Honest Math
Before you sink money into an old furnace, run the numbers — sometimes the smart repair is a new furnace. Here's the framework technicians use.
Repair it when
- The furnace is newer (under ~10–12 years, well within its 15–20-year life).
- The fix is cheap: an igniter, flame sensor, thermostat, or capacitor — the common, affordable repairs.
- It's been reliable and this is a one-off issue, not a pattern.
Replace it when
- The 50% rule trips: the repair tops half the cost of a new furnace on an aging unit.
- It's 15–20+ years old and will likely need more repairs soon.
- The heat exchanger is cracked: a costly repair and a carbon-monoxide risk — usually replace.
- It's nickel-and-diming you with frequent repairs or running inefficiently with rising bills.
Ask the technician for both a repair and a replacement quote — and if you're leaning toward a new unit, our furnace installation calculator prices that.
How to Vet and Hire a Furnace Repair Company
A furnace is a combustion appliance, so hire for licensing and honest diagnosis — not just the lowest service-call fee. Before you book:
- Ask how the diagnostic fee works. Whether it's waived or credited toward the repair should be clear before they arrive.
- Confirm licensing and CO safety. For gas, propane, or oil, they should check for combustion and carbon-monoxide issues, especially the heat exchanger.
- Get the diagnosis in writing. A reputable tech explains which part failed and why, and quotes the specific repair — not a vague bundle.
What a complete quote should spell out
- The diagnosed component and the part-plus-labor cost for that repair.
- How the diagnostic fee and any after-hours/emergency premium are handled.
- Whether a tune-up, CO test, or filter is bundled while the tech is on site.
- The repair warranty and, for an aging furnace, a repair-vs-replace recommendation.
Methodology & Sources
This calculator prices furnace repair per repair, starting from a base cost set by the repair type (failed component, from thermostat to heat exchanger), multiplying by a fuel-type factor and a complexity/age factor, then multiplying by the number of repairs, adding a flat service-timingpremium (after-hours or emergency), applying a minimum job charge, and adding flat add-ons(diagnostic fee, tune-up, duct cleaning, carbon-monoxide test, filter replacement, and a repair warranty). The result is adjusted to your ZIP code's regional price level. In short: Repairs × (Repair Rate × Fuel × Complexity) + Timing + Add-ons, localized by region. Baseline labor is anchored to federal wage data for HVAC technicians and calibrated against our aggregated repair quotes, with carbon-monoxide safety guidance from the U.S. CPSC.
Data sources:
- U.S. Bureau of Labor Statistics — HVAC Mechanics & Installers (SOC 49-9021)
- U.S. Consumer Product Safety Commission — Carbon Monoxide Safety
- ENERGY STAR — Furnace Maintenance
For a full explanation of how every calculator on this site is built and localized, see our methodology page.
About the Reviewer
Licensed Mechanical (HVAC) Contractor
Mechanical contractor specializing in residential HVAC system sizing, replacement, and indoor air quality.
View full profile & credentials →Frequently Asked Questions
Furnace repair typically costs $150 to $700, with most repairs averaging around $300, though a major repair like a heat exchanger can run $1,000 to $2,000+. What's broken drives it: a thermostat is $150 to $350, an igniter or flame sensor $150 to $400 (the most common no-heat fixes), a blower motor or capacitor $300 to $700, a control board or gas valve $400 to $900, and a heat exchanger the most. A service-call/diagnostic fee of $75 to $150 is common (often waived if you proceed with the repair). Fuel type, the furnace's age and parts availability, and after-hours or emergency timing also adjust the cost. Enter the repair, fuel, complexity, and timing in the calculator above for a localized estimate.
The frequent ones are no heat, the furnace not turning on, short-cycling (rapid on-off), a blower not running, strange noises, and weak or uneven heat. The usual culprits are cheap and fixable: a failed hot-surface igniter or a dirty flame sensor (the top no-heat causes), a bad thermostat, a worn blower motor or capacitor, and — surprisingly often — just a clogged air filter, which restricts airflow and triggers overheating shutdowns or short-cycling. More costly failures include the control board, gas valve, and heat exchanger. Noises point to specific parts: banging on startup suggests delayed ignition, squealing a blower belt or bearings, rattling a loose part. A technician diagnoses the exact cause, but many repairs are routine and affordable.
It comes down to age, repair cost, and reliability. Repair makes sense for a newer furnace (under ~10–12 years, well within its 15–20-year life) with an affordable, one-off fix like an igniter, flame sensor, thermostat, or capacitor. Replacement makes more sense when the furnace is 15–20+ years old, when a repair tops roughly 50% of a new furnace's cost (the '50% rule' — a $1,500+ heat exchanger or control board on an old unit is a classic trigger), when it needs frequent repairs, when energy bills are climbing from lost efficiency, or when there's a safety issue. A cracked heat exchanger on an older furnace is both a costly repair and a carbon-monoxide risk, so it usually points to replacement. A good technician will give you both a repair and a replacement quote so you can decide.
Start with the simple stuff, which fixes many cases: the thermostat fan set to 'ON' instead of 'AUTO' blows cold air when the burner isn't firing; make sure it's on 'heat,' 'AUTO,' and set above room temperature. Then check for a clogged air filter (a top cause — it overheats the furnace and shuts off the burner), a tripped breaker or an 'off' furnace switch, and a properly closed access panel (a safety switch stops the furnace if it's open). If those don't do it, the likely causes are component failures — a failed igniter, a dirty flame sensor (ignites then quickly shuts off), a pilot issue on older units, a gas-supply or valve problem, or a control-board fault — which need a technician. The igniter and flame sensor are the most common and most affordable culprits. If you smell gas, leave and call the gas company.
You can safely handle basic troubleshooting and simple fixes — checking the thermostat and its batteries, replacing the air filter, resetting a tripped breaker, making sure the access panel is closed, gently cleaning the flame sensor, and relighting a standing pilot. These resolve a lot of no-heat calls and are worth checking first. But most actual repairs should go to a qualified HVAC technician, because furnaces involve gas (leak, explosion, and carbon-monoxide risk), electrical components (shock), and combustion (safety). Anything touching the gas valve or line, the control board, the blower motor, or especially the heat exchanger is a professional job. And if you smell gas or suspect carbon monoxide, leave the house and call for help immediately — safety comes first with a furnace.
It's the charge for the technician to come out and diagnose the problem — typically $75 to $150 — and it covers the trip and the time to find what's wrong before any repair. Many companies waive or credit it toward the repair if you proceed with the work, so ask up front how they handle it. The diagnosis is genuinely valuable: furnace symptoms often have several possible causes, and a proper diagnosis avoids throwing parts (and money) at the wrong thing. After-hours, weekend, and emergency visits usually add a premium on top of the standard fee. The calculator includes a diagnostic-fee add-on and lets you select standard, after-hours, or emergency timing so the estimate reflects when you need the technician.
Yes. A repair during standard business hours is the baseline; an after-hours or weekend call adds a premium (about $120 here) for the off-hours labor, and an emergency, same-day, or holiday visit adds more (about $200) for the immediate response. Furnaces have a habit of failing on the coldest nights, so it's a common trade-off — if you can safely stay warm with space heaters and layers until morning, scheduling standard-hours service saves the premium. If it's dangerously cold, there are vulnerable occupants, or you smell gas or suspect carbon monoxide, don't wait. The calculator lets you pick standard, after-hours, or emergency timing so your estimate reflects the urgency.
The fuel affects how complex the furnace is and therefore the repair labor. An electric furnace is the simplest — no combustion, gas valve, or flue — so repairs run a bit cheaper (about 10% less here). Natural gas is the baseline and the most common. Propane is very similar to gas (about 5% more). An oil furnace is the most complex to service (about 20% more) because of its combustion system, fuel pump, nozzle, and additional components, plus fewer technicians specialize in oil. The same failed part can cost differently across fuel types because of that surrounding complexity. Select your fuel in the calculator so the estimate reflects your furnace, and note that safety concerns like carbon monoxide apply to all combustion (gas, propane, oil) systems.
Most costly repairs are preventable with cheap, regular maintenance. The two biggest levers are an annual professional tune-up before heating season (often $100–$150), where a technician cleans and tests the burners, igniter, flame sensor, heat exchanger, blower, gas pressure, venting, and safety controls and catches small problems before they cascade — and changing the air filter every 1–3 months, since a dirty filter is behind a huge share of furnace failures (overheating, short-cycling, blower strain). Beyond that, keep the furnace area and vents clear, address odd noises or weak heat promptly instead of ignoring them, and keep carbon-monoxide detectors working. The modest cost of maintenance is far less than a mid-winter emergency repair — the calculator includes tune-up and filter-replacement add-ons.
Yes — it's the most safety-critical furnace failure. The heat exchanger is the metal component that separates the combustion gases from the air blown into your home; a crack can let carbon monoxide, an odorless, colorless, deadly gas, leak into the living space. Signs can include a yellow (instead of blue) burner flame, soot, unusual odors, or a carbon-monoxide detector alarm — but often there are no obvious signs, which is why working CO detectors and annual inspections matter. Replacing a heat exchanger is expensive, so on an older furnace it usually tips the decision toward replacing the whole unit rather than repairing. If you suspect a cracked heat exchanger or a CO detector goes off, shut the furnace off, ventilate, leave, and call a professional. The calculator includes a carbon-monoxide test add-on.