Furnace blowing cold air
Air comes from the vents but it isn't warm.
What you're probably seeing
Air comes from the vents but it isn't warm.
Likely causes
- Thermostat fan set to ON instead of AUTO.
- Ignition problems or a dirty flame sensor.
- Overheating trips the limit switch (often a clogged filter).
Safe checks you can do now
- Set the fan to AUTO.
- Replace the filter.
- Check that the gas valve is on.
When to call a pro
It still blows cold after these checks.
General information about common causes, not a diagnosis of your home.
FAQ
Quick answers
Who fixes furnace blowing cold air?
A heating and cooling company. Call (844) 511-3573 to connect with an independent local heating and cooling company.
How much does it typically cost?
Furnace repair: $125–$480 (ignitor $100–$250, flame sensor $80–$250, blower motor $300–$900) (HomeGuide 2026 national ranges). Your pro sets the real number after seeing the job.
When should I call?
It still blows cold after these checks.
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