The short answer
$100–$300
Often the sensor only needs cleaning, not replacing. Either way it is a short visit, and it is the first thing we check on a furnace that fires and shuts down.
Typical industry ranges for Western Washington — not a quote. Your exact price comes upfront, before any work starts, and you approve it first.
What moves the price
Clean or replace
A sensor coated in white oxide usually cleans up and works for another season. A cracked or burnt one gets replaced — the part is inexpensive.
Whether it is really the sensor
A furnace that quits after seconds can also be a venting or pressure-switch fault. Confirming which is what the diagnosis buys.
How often it keeps happening
A sensor that fouls again within months is telling you about burner or combustion problems underneath. Fixing that is the real repair.
Access and furnace layout
A sensor behind a tight burner assembly takes longer to reach than one on an open panel.
Fires up, then shuts off?
That is the flame sensor most of the time, and it is the cheapest fix on the list. Exact price upfront.
Get My Upfront Quote60 seconds online · or call (206) 486-6373
Typical ranges at a glance
Typical industry ranges for Western Washington — not a quote. Your exact price comes upfront, before any work starts, and you approve it first.
Why homeowners hand it to us
- You approve the price first. Upfront quote before a single screw turns.
- Same-day service. Book in a minute, hear from a tech within 1 business hour.
- 500+ jobs done by 4.9★ rated, professional technicians.
- Fixed right, guaranteed. If it’s not right, we make it right.
Quick answers
What does a bad flame sensor do?
The burners light, run for a few seconds, then shut off — over and over, often ending in a lockout. The furnace is not faulty; it cannot prove the flame is there, so it shuts the gas off on purpose.
Can I just clean it myself?
People do, with fine abrasive. The risks are scratching the rod, bending it out of the flame path, and working around live gas equipment. It is a low-cost job for us to do properly.
It was cleaned last year and it is doing it again. Why?
A sensor that fouls quickly usually means the burners are not burning cleanly, or there is a venting or condensate issue. That is worth finding rather than cleaning again every winter.
Ranges are for websites. Quotes are for you.
Book in 60 seconds — a tech reaches out within 1 business hour and your exact price comes before any work.
Get My Upfront Quote60 seconds online · or call (206) 486-6373
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