How to Replace a Furnace Ignitor
A dead ignitor is a common furnace failure. This guide helps you diagnose the problem, understand replacement costs, and decide whether to tackle it yourself or call a professional.
Replace ignitor if confirmed bad; otherwise troubleshoot further
A cracked ignitor is a definitive sign of failure. If the ignitor looks intact but the furnace won't light, test with a multimeter or have a pro diagnose. Replacing the ignitor yourself is feasible if you understand electrical safety and have the correct part; otherwise, hiring a pro is worth the cost.
What Matters Most
- Visually inspect the ignitor with power off – a white, brittle element with a crack or break means it's dead.
- Use an error code reader or count LED flashes to confirm ignition failure codes.
- A professional ignitor replacement typically costs $170–$380, including the part.
- Hire an HVAC contractor if you're uncomfortable working with 120V electrical components near gas lines.
Strengths
- Clear visual diagnosis: a cracked ignitor is unmistakable.
- Relatively quick and low-cost repair compared to other furnace failures.
- Modern ignitors (silicon nitride) last longer and are less fragile.
Weaknesses
- DIY replacement risks electric shock or ignitor damage from handling.
- Underlying issues like a faulty control board or gas valve can mimic ignitor failure.
- Incorrect installation can lead to unsafe furnace operation.
Ignitor replacement: DIY vs. Pro
| Scenario | Usually do | Why |
|---|---|---|
| Ignitor is visibly cracked | Replace (DIY possible) | Straightforward mechanical swap if you're comfortable with electrical disconnect. Use gloves, avoid touching element. |
| Ignitor looks intact but furnace won't light | Hire a pro | May be a control board, gas valve, or flame sensor issue requiring specialized diagnostics. |
| You have no electrical experience | Hire a pro | 120V shock risk; incorrect wiring can damage the furnace. |
| Furnace is under warranty | Hire a pro | DIY repairs can void the warranty; manufacturer may require certified service. |
Quick Answer
A furnace ignitor glows orange to light the burners. If it's cracked or worn out, the furnace won't produce heat. You can safely inspect the ignitor yourself after turning off power, but replacing it involves 120V electrical work and proximity to gas lines. If you're experienced with electrical repairs and have the exact replacement part, it's a manageable DIY job. For most homeowners, hiring an HVAC technician is the safer, more reliable choice. Typical professional replacement costs $170–$380, including the part and labor.
Diagnosing a Faulty Furnace Ignitor
Before assuming the ignitor is bad, watch for these classic signs. A furnace that tries to start but never lights usually points to the ignitor. Homeowners can perform these safe checks:
- With the thermostat calling for heat, look through the furnace's observation window. Do you see an orange glow near the burners? If not, the ignitor may be dead.
- Listen for a series of clicks followed by the blower running. Many furnaces will attempt ignition three times and then lock out if the ignitor fails. During lockout, an LED light on the control board often blinks a fault code. Refer to our guide on troubleshooting a furnace that won't heat to interpret the code.
- Turn off power to the furnace completely. Remove the access panel and locate the ignitor near the first burner. Visually inspect the grey or metallic element. A hairline crack, white powdery residue, or a break means it must be replaced. Do not touch the element with bare hands.
What Does Ignitor Replacement Involve?
Replacing a furnace ignitor is not routine maintenance—it's a repair. The ignitor is a fragile component that operates at high temperatures. The job requires:
- Sourcing the correct replacement part by matching your furnace model number.
- Turning off electrical power and the gas supply to the furnace.
- Disconnecting the ignitor's wiring harness and removing a mounting screw.
- Installing the new ignitor without touching the heating element (skin oils cause hot spots and premature failure).
- Securing the bracket and reconnecting the wires, then testing the furnace.
Safety Note: Because the ignitor receives 120V power and sits inches from the gas burner, improper installation creates shock and fire hazards. If you are not fully confident performing these steps, do not attempt this repair yourself. Always prioritize safety and hire a licensed HVAC professional.
Ignitor Replacement Costs
| Cost Component | Typical Range | Notes |
|---|---|---|
| Ignitor part (silicon nitride) | $20–$80 | Modern ignitors are more durable and often universal or model‑specific. |
| Professional labor (1 hour) | $150–$300 | Rates vary by region; includes diagnosis, installation, and testing. |
| Total professional repair | $170–$380 | Complex diagnoses or after‑hours service may increase cost. |
These are editorial estimates based on national averages and may not reflect your local market. Use our HVAC Cost Estimator for a personalized range.
Should You Replace the Ignitor or the Whole Furnace?
An ignitor failure alone rarely justifies a new furnace. However, if your furnace is old, inefficient, or has recurring problems, use our Repair or Replace Calculator to weigh the economics. Generally, if the repair cost exceeds 30% of a new furnace's price and the unit is over 15 years old, replacement is the smarter long‑term investment.
Safety Boundaries for Homeowners
HVACDatabase emphasizes safety over savings. Here’s what you can safely do, and what you must leave to professionals.
Homeowner‑Safe Actions
- Visually inspect the ignitor (with power off and panel removed) for cracks or wear.
- Read furnace error codes from the LED light.
- Verify the thermostat is set correctly and the circuit breaker is on.
- Check the air filter—a severely clogged filter can cause overheating and trigger shutdowns that mimic ignitor failure. See our guide on replacing an AC/furnace air filter.
Professional‑Only Work
- Replacing the ignitor if you are unsure about electrical safety or lack the proper tools.
- Diagnosing or repairing gas valves, burners, or heat exchangers.
- Testing or replacing control boards, capacitors, or high‑voltage wiring.
- Any work involving refrigerant or combustion adjustments.
Decision Rules for Homeowners
When to attempt DIY ignitor replacement
- You have prior electrical repair experience and are comfortable working with 120V circuits.
- The ignitor is visibly cracked and the furnace is otherwise in good working order.
- You can source the exact OEM replacement part and follow the manufacturer's instructions.
- You are willing to wear nitrile gloves to avoid contaminating the new ignitor.
When to call an HVAC professional
- You are at all uncertain about turning off gas or disconnecting electrical components.
- The ignitor appears intact but the furnace won't light—the problem may lie deeper.
- Your furnace is more than 15 years old and has needed multiple repairs recently.
- The unit is under warranty; DIY work can void coverage.
Contractor Checklist: Questions to Ask Before Hiring
If you decide to hire a pro, use this checklist to ensure you get a fair deal and quality work:
- Are you licensed, insured, and experienced with my furnace brand?
- Will you provide a written estimate that itemizes parts and labor?
- Do you have replacement ignitors in stock, or will you need to order one (and how long will that take)?
- Can you confirm whether my furnace has a silicon carbide or silicon nitride ignitor, and which you recommend?
- Does the repair come with a warranty on parts and labor? For how long?
- Will you inspect the flame sensor and burners while on site? (Often included in a diagnostic visit.)
- Is there a diagnostic fee, and is it waived if I proceed with the repair?
For help finding and comparing contractors, use our Contractor Comparison Tool and read reviews on HVACDatabase.
Local Climate and Home Considerations
In regions with harsh winters—like the Northeast, Midwest, or mountain states—a failed ignitor means a no‑heat emergency. Keep the number of a reliable HVAC contractor handy, and consider an annual maintenance plan that includes ignitor inspection. In older homes with vintage furnaces, the original silicon carbide ignitor is brittle; if yours cracks, ask the technician about upgrading to a silicon nitride model that’s far more durable.
For coastal or high‑humidity areas, excessive moisture can corrode electrical connections, making ignitor failure more common. Regular seasonal maintenance can catch corrosion early.
Methodology
HVACDatabase cost estimates are editorial figures grounded in multi‑source research, including contractor surveys, service dispatch data, and industry pricing models. We do not guarantee the price a specific contractor will charge. Our recommendations prioritize safety and adhere to ASHRAE and manufacturer guidelines. When considering DIY, we assume a baseline of electrical competence and access to proper tools; if you lack either, we strongly advise hiring a licensed professional.
Frequently Asked Questions
Can I test the ignitor with a multimeter?
Yes, if you are experienced with electrical testing. With power off and the ignitor disconnected, measure resistance across its terminals. A healthy ignitor typically reads between 10 and 150 ohms, depending on the model. Infinite resistance means it’s burned out. But even a passed resistance test doesn't guarantee the ignitor glows correctly under load, so visual inspection is also key.
How long does a furnace ignitor last?
Silicon carbide ignitors often last 3–5 years of regular use. Silicon nitride ignitors, now common in newer furnaces, can last 10 years or more. Frequent cycling, contamination, or voltage spikes shorten lifespan.
Why does my new ignitor keep failing?
Rapid failures suggest dirty air (dust cooking onto the element), a supply voltage problem, or a furnace that short‑cycles. Have a technician verify voltage and check the burner alignment. Also ensure you’re using the correct replacement part—universal ignitors may not match the original specifications exactly.
Will the furnace work if I bypass the ignitor?
Absolutely not. The ignitor is a critical safety component. Bypassing it would allow raw gas to flow without ignition, creating a severe explosion hazard. Never attempt to bypass any safety device.
Does homeowners insurance cover furnace ignitor repair?
Typically no. Ignitor failure is considered normal wear and tear, which is excluded by home insurance. Service contracts or furnace warranties may cover it if the unit is within the warranty period.
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