Why Is My Furnace Not Turning On but Getting Power?
What this costs
| Option | Job | Low | High |
|---|---|---|---|
| Replace | Furnace Replacement | $2,950 | $8,350 |
What to check yourself
We'd stop at these checks. Don't open the burner area, and don't touch the gas valve.
- Thermostat: Carrier lists dead batteries and loose wiring. Make sure it's set to heat and above room temperature.
- Filter: ENERGY STAR says to check it monthly. A clogged one can cause problems, and Carrier lists it among the causes.
- Vents: make sure they aren't blocked, as Carrier also lists.
What a technician looks at
Carrier's list of causes includes a broken igniter, a dirty flame sensor, a pressure switch, a tripped limit switch, or a failed motor, control board or capacitor. On older models, the pilot may have gone out. ENERGY STAR says a pro's check-up includes gas connections, gas pressure, burner combustion and the heat exchanger. We recommend a licensed HVAC technician for all of these.
When it may not be the furnace
Carrier says to contact your utility if other gas appliances stopped working too, since the problem may be gas supply.
Safety first
If you smell gas, leave right away and call your utility or 911 from outside. If a CO alarm sounds, leave and call emergency services. CPSC says early carbon monoxide signs resemble the flu without a fever, such as headache and nausea.
Furnace Won't Turn On? Safe Checks Before You Call
Common questions
Why does the blower run but no heat comes on?
What does a lockout mean?
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Last verified 2026-11-04
- Carrier: Furnace not turning on — Ignition failure, flame sensor, pressure switch, thermostat, filter, limit switch, gas supply; lockout; when to call; safety.
- U.S. Consumer Product Safety Commission: Carbon monoxide fact sheet — Furnaces can malfunction and produce CO; symptoms; leave and call.
- ENERGY STAR: Maintenance checklist — Check filters monthly; pros check gas connections, burner combustion and heat exchanger.
- Public Service Commission of Wisconsin: Natural gas consumer safety — If you smell gas, leave immediately and call the gas utility's emergency number or 911 from a safe distance outdoors; odor described as rotten eggs, sulfur or garlic.
General information, not professional advice. Conditions, codes and prices vary. Turn off power, gas or water before any work, and hire a licensed professional when in doubt. Cost figures are our estimates, not quotes.