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Furnace Blowing Cold Air

A furnace blowing cold air often means the burners never lit, the system is still in fan-only mode, or a limit switch tripped. Check the filter and thermostat first; ignition repairs typically run $150–$600.

Reviewed July 2026

What does furnace blowing cold air mean?

Cold air from your vents usually means the blower is running but the burners aren't producing heat. Common causes include a dirty filter restricting airflow, a failed ignitor, or a limit switch that shut the burners down. Fan-only mode on the thermostat can also feel like cold air.

What usually causes furnace blowing cold air?

Failed hot-surface ignitormost common

Typical repair: $150–$400

Clogged air filtercommon

Typical repair: $20–$75

Limit switch tripped from overheatingcommon

Typical repair: $150–$600

Find your exact error code

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

Lennox271Pressure-switch retry lockoutGoodmanE0Excessive retries or recyclesGoodmanE3Limit circuit openedCarrier14Ignition lockoutRheem11Failed ignition

What should I check first when furnace blowing cold air?

  1. Replace or clean the air filter.
  2. Confirm the thermostat is set to Heat, not Fan Only or Cool.
  3. Wait five minutes after a limit trip — the furnace may reset on its own.
  4. Listen for ignition clicks; if none, the ignitor may have failed.

What a repair costs

A furnace ignitor replacement typically costs between $150 and $400 nationally.

Typical repair cost
$150 – $400furnace ignitor replacement
Where the money goes
Part $25–$100Labor $50–$375Typical labor time: 0.5–1 hrs

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