How to Replace a Furnace Igniter in 6 Steps (DIY or Pro?)

TL;DR: A failed furnace igniter is the #1 reason a gas furnace won't fire. The part costs $15–40 and takes 20 minutes to replace if you're comfortable cutting power and handling screws. If the igniter glows but the burner doesn't light, or if you smell gas, call an HVAC tech—there's a deeper issue with the gas valve or flame sensor.

_Last reviewed: July 2026 · 5 min read_

Your furnace clicks, the blower starts, but no heat comes. Nine times out of ten, the hot-surface igniter has cracked or aged out. These silicon-carbide or silicon-nitride rods glow orange-hot to ignite the gas; after 3–7 years they weaken and break. Replacing one is a straightforward swap if you follow the six steps below and know when to stop.

Okoniq Property Hub lets you log the igniter brand, purchase date, and replacement labor so you can track furnace part lifecycles and catch the next failure before a tenant calls at 2 a.m.

How do I know the igniter is the problem?

Turn the thermostat up and watch the furnace sequence. You should hear the inducer fan start (a whirring sound), then see the igniter glow bright orange through the burner viewport. If it glows for 15–30 seconds but the burners never light, the igniter is weak or the flame sensor is dirty. If the igniter doesn't glow at all, it's cracked or the control board isn't sending voltage. Pull the igniter and inspect it under light—any hairline crack means replace it.

If the igniter glows, the burners light for a second, then shut off, suspect a fouled flame sensor or a pressure-switch issue. That's a different repair. If you smell gas during this test, shut off the furnace breaker and the gas valve at the unit, open windows, and call a licensed HVAC tech immediately.

What tools and parts do I need?

You need a flathead and Phillips screwdriver, a 1/4″ or 5/16″ nut driver (depends on your furnace brand), a flashlight, and the replacement igniter. Match the part number printed on the old igniter or use your furnace model number at an HVAC supply house or Amazon. Generic "universal" igniters work for many Carrier, Trane, Goodman, and Rheem units, but verify the connector type (two-prong or three-prong) and mounting-hole spacing before you buy. Expect $15–25 for an aftermarket part, $40 for OEM.

Wear nitrile gloves when handling the new igniter—skin oils shorten the life of silicon-carbide elements. Do not touch the ceramic rod with bare fingers.

How do I replace the igniter step by step?

1. Cut power. Flip the furnace breaker and the furnace's 120 V switch (usually a red toggle on the side of the unit or at the top of the basement stairs). Wait 60 seconds for capacitors to bleed down.

2. Remove the access panel. One or two sheet-metal screws hold the lower burner-compartment door. Slide or lift it off.

3. Locate the igniter. It sits in front of the burner assembly, a ceramic rod with a metal bracket. The wire harness plugs into the back. Take a photo of the wiring and bracket orientation before you touch anything.

4. Disconnect the wire. Pull the plug—do not yank the wires. Some older igniters have screw terminals; loosen both screws and pull the wires straight off.

5. Unbolt the bracket. Typically two hex screws or nuts secure the igniter bracket to the burner box. Support the igniter with one hand so it doesn't fall and shatter when the second screw comes out.

6. Install the new igniter. Slide the new one into the bracket, bolt it down (snug but not torqued—ceramic cracks under stress), plug in the connector, and replace the access panel. Restore power, set the thermostat 5°F above room temp, and watch the igniter glow and the burners light. Let the furnace run a full cycle (10–15 minutes) and confirm the blower shuts off cleanly.

Log the date, part number, and supplier in Okoniq's maintenance tracker so you know when this igniter is due for its next replacement.

When should I call a pro instead?

If you've never opened the furnace or you're unsure which breaker controls it, hire an HVAC tech for the $150–250 service call. If the new igniter glows but the burners still don't light, the gas valve, flame sensor, or pressure switch needs diagnosis—those require a multimeter and an understanding of the control sequence. If you smell gas at any point, stop and call a licensed technician.

Landlords in jurisdictions with strict habitability timelines (24–48 hours to restore heat in winter) should keep a spare igniter on hand and know a 24-hour HVAC contractor. A $30 part you can swap in 20 minutes beats a $400 emergency call and a code violation. For attic-mounted furnaces, factor in safe access and working space—if the unit is in a crawl attic, pay the pro.

What maintenance extends igniter life?

Change the furnace filter every 30–90 days. A clogged filter starves airflow, forces longer run cycles, and overheats the igniter. Inspect the flame sensor annually and wipe it with fine-grit sandpaper or a dollar bill to remove carbon buildup—dirty sensors cause short-cycling that stresses the igniter. Schedule a fall tune-up every other year; a tech will test igniter amperage draw and catch a weak element before it fails mid-winter.

If you have baseboard heat in some rooms and forced air in others, make sure the furnace zone dampers close properly so the igniter isn't firing unnecessarily. Document every filter change and tune-up in Okoniq so you can prove maintenance history to an insurance adjuster if a failure causes freeze damage.

FAQ

How long does a furnace igniter last?

Hot-surface igniters last 3–7 years depending on furnace run hours and filter maintenance. Units in rentals with poor filter discipline fail closer to 3 years; owner-occupied homes with quarterly filter swaps reach 7. Silicon-nitride igniters (white ceramic) outlast silicon-carbide (orange-gray) by 1–2 years but cost $10 more.

Can I clean and reuse a cracked igniter?

No. Any visible crack means the element is compromised and will fail mid-cycle or fail to glow at all. Cleaning carbon deposits with a soft brush works only if the igniter is intact and merely dirty, which is rare. Replace cracked igniters—they're not worth troubleshooting.

Why does my new igniter glow but the burners don't light?

The flame sensor is dirty or the gas valve isn't opening. Wipe the flame sensor rod with fine sandpaper, reassemble, and retry. If that doesn't work, check that the gas valve handle is parallel to the pipe (open position) and listen for a click when the igniter glows—that's the valve energizing. No click means a failed gas valve or a control-board issue; call a tech.

Is it safe to replace an igniter myself?

Yes, if you cut power at the breaker, don't touch live wires, and don't smell gas. The igniter circuit is low-voltage when the furnace is off. The risk is damaging the new igniter by over-torquing screws or touching the ceramic with bare fingers, not electrical shock. If you're uncomfortable working inside the furnace or your unit uses a standing pilot instead of electronic ignition, hire a pro.

How much does a pro charge to replace a furnace igniter?

HVAC techs charge $150–250 for a service call that includes diagnosis and igniter replacement. The part is marked up to $60–100 in the invoice. Emergency after-hours calls run $300–500. DIY saves $100–200 if you already have the correct part and 20 minutes.

This is educational information, not professional HVAC or safety advice. If you smell gas, suspect a gas-valve failure, or are unsure which breaker controls your furnace, call a licensed HVAC technician before opening the unit.