Updated October 2026. Furnace ignitor replacement is the fix when a gas furnace clicks, tries to start and never lights: the ignitor is the small part that gets hot enough to light the burners, and when it cracks or wears out, the furnace locks itself out and blows cold air or nothing at all. Most hot surface ignitors last about 3 to 7 years (Bryant). At Home Comfort Alliance, an ignitor replacement costs $353 to $821 (prices as of September 2026); see our furnace repair cost guide for how that compares with other repairs.
Below: the signs your ignitor has failed, how to tell it apart from a flame sensor problem, the types of ignitors, why some fail early, and when a new ignitor stops making sense on an older furnace. If your furnace is out now, see furnace repair in Seattle-Tacoma.
What does a furnace ignitor do?
When your thermostat calls for heat, the furnace runs a short start-up sequence: the draft inducer fan clears the burner area, a pressure switch confirms the vent is drawing, the ignitor heats up, and then the gas valve opens so the burners light off the hot ignitor. A flame sensor then proves there is a flame. If any step fails, the control board shuts the gas off and tries again, usually up to three times, before it locks out for a while.
Most gas furnaces made in the last 25 years use a hot surface ignitor: a ceramic element that glows bright orange in a few seconds. Older furnaces may use a spark ignitor or an intermittent pilot instead (Carrier). Electric furnaces and heat pumps have no ignitor at all.
Signs your furnace ignitor has failed
A bad ignitor shows up the same way in almost every home: the furnace tries to start, then gives up. Watch for these signs:
- The furnace clicks and hums but never lights. You hear the inducer fan start, then nothing, then the cycle repeats.
- No orange glow through the sight glass. On most furnaces you can see the ignitor through a small window in the burner door. If it never glows during start-up, it is the prime suspect.
- The furnace locks out after a few tries. A blinking light on the control board, often with a code for “ignition failure”, and no heat for an hour or more.
- Cold air from the vents. On some furnaces the blower runs even though the burners never lit. See why your furnace is blowing cold air for other causes.
- Heat that works some days and not others. A cracked ignitor can still glow when it is warm and fail on a cold start.
If the ignitor glows bright orange but the burners still don’t light, the ignitor is probably fine and the problem is elsewhere, most often the gas valve or the control board. A loud bang when the burners finally do light is delayed ignition, a different problem covered in why your heater is making a loud noise.
Ignitor or flame sensor?
The two parts sit side by side and both stop the heat, so they are easy to mix up. The quickest way to tell them apart is what happens right after the burners light.
| Part | What it does | What you see when it fails |
|---|---|---|
| Ignitor | Heats up to light the gas | No glow, no flame; the furnace never lights |
| Flame sensor | Proves a flame is burning so the gas stays on | Burners light, then shut off after a few seconds, over and over |
| Gas valve or control board | Opens the gas and runs the start-up sequence | Ignitor glows, but the burners never light |
A dirty flame sensor is one of the most common furnace repairs, and it is often confused with an ignitor failure. A technician tests both before replacing either, so you don’t pay for a part you didn’t need.
Types of furnace ignitors
Your furnace’s model decides which ignitor it takes. The main types:
| Type | Where you find it | Notes |
|---|---|---|
| Hot surface, silicon carbide | Many furnaces from the 1990s and 2000s | Brittle; Bryant notes it can crack from repeated heating and cooling |
| Hot surface, silicon nitride | Most newer gas furnaces | Built to resist thermal shock (Bryant); usually longer lived |
| Spark ignitor | Some furnaces and boilers | Clicks rapidly at start-up, like a gas grill |
| Intermittent pilot | Older mid-efficiency furnaces | A spark lights a small pilot, which lights the burners |
Sources: Carrier and Bryant, checked October 2026.
Universal replacement ignitors exist, and they can work, but the fit, mounting and resistance have to match your furnace. A technician will usually fit the manufacturer’s part or a listed equivalent so the furnace keeps lighting the way it was designed to.
How long do furnace ignitors last, and why do some fail early?
Bryant puts the typical life of a hot surface ignitor at around 3 to 7 years. Some last far longer; some fail in a single season. The usual reasons an ignitor dies early:
- Short cycling. Every start heats and cools the element, so a furnace that turns on and off too often wears out its ignitor faster. See furnace short cycling in our marine climate.
- Touching the element. Oil from fingers creates hot spots that crack the ceramic. Manufacturers warn never to touch it.
- High or unstable voltage to the furnace, which runs the element hotter than designed.
- Dust and debris on the element, including drywall dust after a remodel.
- Water on the burner area, for example from a blocked condensate drain on a high-efficiency furnace.
A yearly furnace tune-up ($230, or $180 for Home Comfort Club members) covers the burner assemblies, safety controls, wiring and gas pressures, which is where many early ignitor failures start.
What does ignitor replacement cost?
Home Comfort Alliance charges $353 to $821 to replace a furnace ignitor (prices as of September 2026). The range covers a factory (OEM) ignitor, installed and tested; the high end applies when a second part has also failed, such as the control board. Our dispatch fee ($119) and diagnostic fees ($72 standard, $130 deeper) are listed separately, and you approve an upfront price before any work begins.
Our trucks are fully stocked, so most repairs can be handled on the spot. For every common furnace part side by side, with regional benchmarks, see the furnace repair cost guide. Current offer: $50 off HVAC service or repair (not combined with Club pricing).
Can I replace a furnace ignitor myself?
Some homeowners do, but Carrier calls DIY ignitor replacement risky: the element is extremely fragile, and it sits next to the gas burners. We don’t recommend DIY work on gas appliances. If you are handy and want to check things safely before calling, you can:
- Make sure the thermostat is set to heat and a few degrees above room temperature.
- Check the furnace switch (it looks like a light switch on or near the furnace) and the breaker.
- Replace a dirty filter.
- Look through the sight glass during a start attempt to see whether the ignitor glows, without removing any panels.
Leave the rest to a technician, who tests the ignitor’s resistance and the control board’s output before swapping parts, and checks the rest of the start-up sequence while the furnace is open. If you ever smell gas, stop and leave the home, then call your gas utility or 911 from outside; see what to do if you smell gas near your furnace.
New ignitor or a new furnace?
An ignitor is a small repair, so on most furnaces it is worth doing. The question changes on an old furnace that needs other work too. A common rule of thumb is the $5,000 rule: multiply the furnace’s age by the repair cost, and if the result is over $5,000, get a replacement price as well. ENERGY STAR suggests considering replacement once a furnace is more than 15 years old.
See furnace repair vs. replacement for the full decision, and furnace replacement if you are leaning that way. Replacement estimates are free; repair visits carry the dispatch fee above.
Furnace ignitor FAQ
How do I know if my furnace ignitor is bad?
The furnace clicks and the inducer fan runs, but the ignitor never glows orange and the burners never light. After a few tries the furnace locks out. A technician confirms it by testing the ignitor’s resistance and the voltage the control board sends to it.
How long does a furnace ignitor last?
Bryant puts a hot surface ignitor at around 3 to 7 years. Short cycling, dust, high voltage and touching the element can shorten that.
Is the ignitor the same as the flame sensor?
No. The ignitor lights the gas; the flame sensor proves the flame is there. A bad ignitor means the burners never light. A dirty flame sensor means the burners light and then shut off after a few seconds.
Why does my ignitor glow but the furnace won’t light?
If the ignitor glows bright orange and the burners still don’t light, the gas valve, the control board or the gas supply is the more likely cause. Have a technician test them rather than replacing the ignitor.
Can I use a universal ignitor?
Sometimes. A universal ignitor has to match your furnace’s mounting, element position and electrical rating. Technicians usually fit the manufacturer’s part or a listed equivalent.
Can I replace a furnace ignitor myself?
Carrier calls it risky because the element is fragile and sits next to the gas burners. We recommend a technician, who tests the circuit first so you only replace the part that failed.
Will my furnace run without an ignitor?
No. A gas furnace with a hot surface ignitor cannot light its burners without it. It will try, fail and lock out.
Why do furnace ignitors fail early?
Frequent on-off cycling, oil from fingers on the element, high voltage, dust and moisture in the burner area are the usual causes.
How much does a furnace ignitor replacement cost at Home Comfort Alliance?
$353 to $821 (prices as of September 2026) for a factory (OEM) ignitor, installed and tested, with the dispatch and diagnostic fees listed separately. The high end applies when a second part, such as the control board, has also failed. The furnace repair cost guide compares it with other furnace repairs.
Should I replace the ignitor or the whole furnace?
On most furnaces the ignitor is worth replacing. On an older furnace that needs several repairs, multiply its age by the repair cost; if that is over $5,000, get a free replacement estimate too.
Furnace won’t light?
NATE-certified technicians test the ignitor, flame sensor and controls, and give you an upfront price before any work begins. After-hours emergency heating and cooling service for qualifying emergencies ($330 after-hours fee).
Get an estimate
A local comfort advisor will call you to set up your visit.
Sources: Bryant, furnace ignitor; Carrier, furnace ignitor; ENERGY STAR, when to replace heating and cooling equipment. Checked October 2026.