Independent guide
Furnace blowing cold air
The furnace runs, but the air from the vents is cold. Start here.
Check these first
- Thermostat is set to Heat and the target is above room temperature.
- Replace the thermostat batteries if it has any.
- Check the air filter.
- Make sure vents and returns are not blocked.
Still not working? That's a job for a pro.
When to call a pro
The problem is still there after these checks. Anything inside the unit is a job for a pro.
Questions
Why is my furnace blowing cold air?
A dirty air filter slows airflow and makes the system work harder. Check the filter and make sure vents are open. If the air stays cold, have a technician look at the system rather than working inside the furnace.
Source: energystar.gov
Is cool air from a heat pump in winter normal?
If your system is a heat pump, brief cool air can be normal during its defrost cycle. In ductless systems the indoor unit may put off some cooling to warm the outdoor coil. If cool air persists or coils stay frozen, call an HVAC professional.
Source: bsesc.energy.gov
Why are some rooms too cold while others are warm?
ENERGY STAR says rooms that are too hot or too cold can come from improper equipment operation, duct problems or too little insulation. Check that vents are not blocked by furniture, then ask an HVAC professional to look at the system and ducts.
Source: energystar.gov
Can a technician fix cold-air problems during a tune-up?
A professional check-up includes inspecting the controls so the system starts, runs and shuts off properly. If your furnace blows cold air, scheduling a technician is safer than trying repairs on gas or electrical parts yourself.
Source: energystar.gov
Describe the problem
What kind of system is it?
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