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Property Damage or an Urgent Repair in MD, DC or VA? Call (240) 695-4415 to Confirm Availability★Property Damage or an Urgent Repair in MD, DC or VA? Call (240) 695-4415 to Confirm Availability★Property Damage or an Urgent Repair in MD, DC or VA? Call (240) 695-4415 to Confirm Availability★Property Damage or an Urgent Repair in MD, DC or VA? Call (240) 695-4415 to Confirm Availability★
HVAC Problem

Furnace Blowing Cold Air

When your furnace runs but the air coming out is cold, it usually means the burners are not staying lit or a safety control has shut down the heat. Some causes are simple; others need a technician. Here is how to tell.

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Common Causes

Thermostat Set to “On”

With the fan set to ON instead of AUTO, it blows even between heating cycles, pushing room-temperature air. A quick setting check rules this out.

Flame Sensor or Ignitor Failure

A dirty flame sensor or cracked ignitor causes the burners to light and then shut off, so the blower pushes cold air.

Overheating / Clogged Filter

A clogged filter or blocked airflow trips the high-limit switch, cutting the burners while the fan keeps running.

Warning Signs

  • !Air from vents is cool or room-temperature
  • !Burners light briefly then go out
  • !Frequent short cycling
  • !A clicking ignition that never catches

How We Fix It

  1. 1Confirm thermostat settings and replace a dirty filter.
  2. 2Clean the flame sensor, inspect the ignitor, and check the high-limit and gas supply.
  3. 3Test a full heating cycle to confirm steady, warm output.

What It Costs

Most cold-air furnace repairs (flame sensor, ignitor, filter, controls) run $120-$600. Heat exchanger or gas valve issues are quoted after diagnosis.

If You Ignore It

A furnace that short cycles wears components fast, and some causes (like a cracked heat exchanger) are safety risks. Get it diagnosed before the cold snap leaves you without heat.

Frequently Asked Questions

Is cold air from the furnace dangerous?+
Not always, but a furnace that short cycles or has a cracked heat exchanger can be. If you smell gas or burning, shut it off and call us immediately.
Can I fix it myself?+
Check the thermostat is on AUTO and swap a dirty filter. If that does not solve it, the next steps involve burners and safety controls best left to a technician.
How fast can you get to a no-heat call?+
In winter we prioritize no-heat calls and respond within 24 to 48 hours. Call (240) 695-4415 for the next available visit.

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