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Furnace Won't Turn On

A furnace that won't turn on at all usually has no power, a tripped breaker, a closed gas valve, or a thermostat that isn't calling for heat. Check those basics first; professional diagnosis typically runs $100–$400.

Reviewed July 2026

What does furnace won't turn on mean?

When nothing happens — no hum, no click, no blower — the problem is often outside the furnace itself. Power, the thermostat, or the gas supply are the first places to look. If those check out, the issue may be an internal safety lockout or failed control board.

What usually causes furnace won't turn on?

Tripped breaker or blown fusemost common

Typical repair: $300–$800

Thermostat not calling for heatcommon

Typical repair: $100–$400

Closed gas valve or safety lockoutcommon

Typical repair: $350–$900

Find your exact error code

Select your furnace brand to jump to the code page for this symptom.

Lennox200Rollout circuit hard lockoutCarrier14Ignition lockoutGoodmanE0Excessive retries or recyclesRheem10One-hour ignition lockoutDaikinE0Excessive retries or recycles

What should I check first when furnace won't turn on?

  1. Confirm the thermostat is set to Heat and the temperature is above room temp.
  2. Check the furnace power switch and the breaker in your electrical panel.
  3. Verify the gas supply valve near the furnace is fully open.
  4. Replace thermostat batteries if the display is dim or blank.

What a repair costs

A control board replacement typically costs between $300 and $800 nationally.

Typical repair cost
$300 – $800control board replacement
Where the money goes
Part $100–$350Labor $0–$700Typical labor time: 1–2 hrs

This is general information, not professional advice. Gas, electrical, and combustion repairs can be dangerous — when in doubt, call a licensed technician.