How often should you replace a furnace igniter?
Updated July 2026
Plan to replace a hot-surface furnace igniter every 3 to 7 years, and many HVAC techs swap it proactively during the annual tune-up rather than wait for it to crack. The element is a thin ceramic bar (silicon carbide on older furnaces, tougher silicon nitride on newer ones) that glows to well over 1,800°F to light the gas, and every heat cycle leaves it more brittle. The part is $15 to $50 to fit yourself or $150 to $350 installed, cheap insurance against a no-heat call in January.
What changes the interval
| Your situation | Interval | Why |
|---|---|---|
| Silicon carbide igniter (older furnaces) | Every 3–5 years | The brittle flat-bar type cracks readily from thermal cycling |
| Silicon nitride igniter (newer furnaces) | Every 5–7 years | A tougher element that tolerates more on-off cycles |
| Furnace that short-cycles | Sooner | Every extra ignition cycle ages the element faster |
| Any time the burner cover is off | Inspect for hairline cracks | A fracture that ends the glow does not always show |
| Proactive swap at the 5-year tune-up | Replace now | A $30 part beats a midnight no-heat call |
| Glows but the gas never lights | Replace now | Resistance has drifted and the surface runs too cool |
The cost of skipping it
What skipping it costs: a hot-surface igniter almost always cracks on a cold night when the furnace cycles hardest, and it dies with no warning glow. An after-hours no-heat call runs $150 to $350 for a part that costs $15 to $50 on the shelf, and emergency rates climb higher on holidays and weekends. In a hard freeze, a furnace down overnight also puts pipes at risk. A labeled spare igniter turns that crisis into a ten-minute fix.
How to do it (20 minutes · DIY, or $150–350 installed)
- Kill the power at the furnace switch or breaker, and shut off the gas.
- Open the burner compartment and find the igniter: a small ceramic element mounted at the edge of the burner assembly on two wires.
- Note the part: photograph the terminal plug, or buy a universal hot-surface igniter kit and match the mounting bracket.
- Unplug the old igniter and remove its screw. Handle the new one by the ceramic base only, since skin oil creates hot spots that shorten its life.
- Mount the new igniter, reconnect the plug, close the compartment, and restore gas and power.
- Run a heat cycle and confirm the igniter glows, the burners light, and the flame holds. See the full igniter how-to for model specifics.
Knowing the interval is the easy half. OnOtto reminds you at the right interval, and it won't let you snooze it into next year. Tasks persist until they're done, and completing furnace igniter swaps schedules the next one automatically.
Put this on autopilot, free for 30 daysFrequently asked questions
How do I know it is the igniter and not the flame sensor?
Watch a start cycle. If the igniter never glows orange, the igniter, its wiring, or the board is the suspect. If it glows, the burners light, then the flame dies a few seconds later, that is usually a dirty flame sensor rather than the igniter. A cracked igniter often reads open on a multimeter (no continuity) while a healthy one shows resistance. See why a furnace igniter won’t glow for the full diagnostic path.
Can I use a universal igniter or do I need the exact OEM part?
A universal hot-surface igniter kit fits most furnaces and costs less than the OEM part, but you have to match the mounting bracket and terminal plug and follow the kit’s orientation. Silicon nitride universal igniters are sturdier than the flat silicon carbide bars they often replace. For a warranty-age furnace or an unusual mount, the exact OEM igniter removes the guesswork. Either way, touch it only by the ceramic base.
Why do furnace igniters keep failing so fast?
Three usual culprits: bare-finger handling that leaves oil hot spots, constant short-cycling from a dirty flame sensor or an oversized furnace, and plain thermal fatigue after thousands of cycles. Line-voltage igniters also take a beating from voltage spikes. If you are replacing igniters every year or two, fix the underlying short-cycling instead of just swapping the part; the igniter is the symptom, not the disease.
Is it worth keeping a spare igniter on hand?
Yes, and it is the smartest $15 to $50 a furnace owner can spend. Igniters fail on the coldest nights, exactly when technicians are booked out and charging emergency rates. A labeled spare that matches your furnace turns a two-day no-heat wait into a ten-minute swap. Store it in its original packaging so the ceramic stays clean and oil-free, and replace the spare the moment you use it.