Furnace pilot light out? How to relight it safely
First, check whether you even have one: most furnaces built since about 2010 have no standing pilot — they use electronic ignition. If yours does have a pilot, relighting it is straightforward — turn the gas off, wait five minutes, then light — and here's the safe sequence, plus why it won't stay lit.
Don't light anything. Leave the house and call your gas utility or 911 from outside. Then call (888) 810-2291 for a licensed local pro.
Do you even have a pilot light?
Before you try to relight anything, confirm your furnace actually has a standing pilot. A standing pilot is a small flame that burns continuously to light the main burner — common on furnaces built before about 2010. Newer furnaces use electronic ignition, a hot-surface igniter or spark that fires only on demand, with no standing flame to go out.
If that's you, skip the relight — a furnace that won't ignite is a repair, covered on furnace not turning on.
How do you relight a furnace pilot light?
If you do have a standing pilot, relighting follows three steps. Treat the printed instructions on your furnace's label as the authority — they override any general guide — but the sequence is nearly always this:
Turn the gas off and waitStep 1
Turn the gas control knob to OFF and wait a full five minutes so any gas that built up can clear. If you smell gas at any point — a rotten-egg odor — stop here, leave the house, and call your gas utility or 911 from outside. Never relight in the presence of gas.
Set to PILOT and light itStep 2
Turn the knob to PILOT, press and hold the reset button down, and hold a long lighter or match to the pilot orifice until the small flame catches. Keep the button held down for 30–60 seconds after it lights so the thermocouple heats up.
Release and restore powerStep 3
Slowly release the button — the pilot flame should stay lit. If it does, turn the knob to ON, and the main burner should fire on the next call for heat. If the flame goes out when you release, that points to the thermocouple.
Get a licensed HVAC tech on the phone
If the pilot won't light or won't stay lit, one call routes you to a licensed local contractor — 24/7, nationwide. The call is free.
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Why won't my pilot light stay lit?
If the pilot lights while you hold the button but goes out the moment you release it, the usual culprit is a failed thermocouple — the safety sensor that proves the flame is present. When it can't sense the flame, it tells the gas valve to shut off within seconds. A dirty pilot orifice or a strong draft can also snuff a pilot. A one-off outage from a draft is fine to relight; a pilot that keeps going out, burns weak or yellow instead of blue, or won't stay lit at all is telling you something needs a repair.
What does it cost to fix?
Relighting a pilot yourself costs nothing. If the pilot won't stay lit, the common repair is replacing the thermocouple — a small, inexpensive part — which typically runs $75–$250 with labor. A dirty pilot orifice that needs cleaning is in the same range. Anything involving the gas valve itself costs more; the visit fee is on HVAC service call cost.
Pilot won't stay lit?
Enter your ZIP — we'll connect you to a licensed local contractor to replace the thermocouple and check the gas valve. The call is free, 24/7.
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When should you call a pro?
Call when the pilot won't stay lit after a proper relight, when it keeps going out, when the flame looks weak or yellow rather than a crisp blue, or any time you smell gas. A pilot that repeatedly fails, or a burner that lights with a delayed "whoomp," can also point to a combustion or venting problem worth a professional's eyes — and a cracked heat exchanger is the serious version of that, covered on carbon monoxide & cracked heat exchangers. If your furnace has electronic ignition and won't fire at all, start with furnace troubleshooting.
Frequently asked questions
Does my furnace even have a pilot light?
Probably not, if it was made in the last 10–15 years. Furnaces since roughly the 2010s use electronic ignition — a hot-surface igniter or spark — with no standing flame. If there's no little flame and no PILOT setting on the gas valve, you have electronic ignition, and there's nothing to relight.
How do you relight a furnace pilot light?
Turn the gas knob to OFF and wait five minutes to clear any gas, then turn it to PILOT, hold the reset button, and light the pilot with a long lighter, holding for 30–60 seconds. Release the button; if the flame stays, turn the knob to ON. Always follow the exact steps printed on your furnace.
Why won't my furnace pilot light stay lit?
The most common reason is a failed thermocouple — the safety sensor that proves the flame is present. When it can't sense the flame, it shuts the gas off within seconds of you releasing the button. A dirty pilot orifice or a strong draft can also be to blame.
What is a thermocouple and what does it cost to replace?
A thermocouple is a small metal probe in the pilot flame that generates a tiny voltage to tell the gas valve the pilot is lit. When it fails, the pilot won't stay on. Replacing one is a common, inexpensive repair — usually about $75–$250 with labor.
Should I relight the pilot myself?
For a one-off outage — a draft blew it out and it relights and stays lit — yes, following your furnace's printed steps. If it won't stay lit, keeps going out, the flame is weak or yellow, or you smell gas, stop and call a professional instead of forcing it.
Is it safe to relight a pilot light?
It's a routine task when done correctly, but gas demands respect: turn the valve off and wait five minutes first, and if you ever smell gas, leave and call from outside rather than lighting anything. If you're not comfortable, a technician can do it and check why it went out.
My furnace has no pilot and won't ignite — what now?
That's an electronic-ignition furnace, and no ignition is a repair rather than a relight — often a failed igniter or flame sensor. Work through our furnace-not-turning-on guide, and if the igniter or sensor is the culprit, that's a job for a technician.