Furnaces are for heating, so they shouldn’t blow cold air. When the furnace kicks on, air from your vents may briefly feel cool because air already in the ducts reaches the vents before newly heated air does. However, if your furnace is blowing cold air constantly or isn’t keeping up with the desired temperature, you may need a furnace repair.
Why Should You Care if Your Furnace Is Blowing Cold Air?
Cold air doesn’t do anything to warm your home, which is a major issue when Detroit’s average winter low temperatures fall to around 20 to 25 degrees Fahrenheit (and can fall below zero on some winter days and nights).
However, a furnace blowing cold air creates other concerns:
- Safety issues: If a clogged filter or other blockage keeps a furnace from operating effectively, the restricted airflow can create air quality issues. Heat that doesn’t escape into your home may build up in the furnace, leading to a cracked heat exchanger and the potential for a carbon monoxide leak. If your carbon monoxide alarm sounds, leave immediately and call 911 from outside.
- Failed igniter: If you have a gas furnace, cold air could mean the igniter didn’t light or that you have another gas supply problem. Without the flame or gas supply, your unit can’t heat the air to circulate it through your home.
- Wasted energy: If your furnace isn’t heating the air enough, it won’t warm your home effectively. If your furnace runs and then shuts off or seems to run all the time, you could be spending a lot more than necessary on your heating bill.
- Property damage: If your home isn’t warming properly during a serious Detroit cold snap, pipes could freeze or burst, leading to expensive repairs.
Why Is Your Furnace Blowing Cold Air?
If your furnace is running but blowing cold air, it might be due to a small issue that’s an easy DIY fix. In other cases, you may have a bigger issue brewing that calls for professional heating repair.
Problems With Thermostat Settings
If your thermostat is set to a manual “on” position, the fan might be blowing all the time. That’s true even when the furnace isn’t creating warm air. When troubleshooting cool airflow, switch the fan to “auto” so it doesn’t continually circulate unheated air between heating cycles.
Also check that your thermostat hasn’t been accidentally switched to cool and that it’s set to your preferred temperature.
A Dirty or Clogged Air Filter
If your system’s not running efficiently, it may overheat. This can cause safety switches to shut down burners or other functions, which leads to a system blowing only cold air. Check your air filters and replace them as needed. Also check the vents and registers throughout your home to ensure none are blocked by furniture, rugs or other objects.
The Pilot Light Is Out
If the blower runs, but you’re not getting hot air — and you have an older gas furnace with a standing pilot — double-check that the pilot light didn’t go out. Follow your furnace manufacturer’s instructions before attempting to relight it, and never do so if you smell gas. Leave igniter or thermocouple repairs to a professional.
Your Gas Supply Is Low or Off
If you have a gas furnace, make sure you have fuel for it. If your gas service is interrupted, the furnace won’t produce heat, although the blower may continue running. If you suspect a gas leak, leave your home immediately and call 911 and your gas utility from a safe location.
When to Call a Furnace Professional
Many things can go wrong with a furnace that call for professional repair, such as:
- Leaky ductwork. If your ductwork is in disrepair or worn out from age, you may need a professional to inspect and patch it up. Leaky ductwork allows heat to escape your system where you don’t want it, such as unfinished basements or attics.
- Control board or wiring issues. Electrical problems can disrupt ignition or thermostat operation, causing your furnace to blow unheated air.
- Clogged or frozen lines. When condensate lines on certain furnaces don’t drain properly, the safety switch may shut off the furnace burners, leading to cold air.
- An aged or undersized furnace. An older furnace may struggle to maintain the temperature you want as it nears the end of its lifespan, while an undersized system may not have enough heating capacity for your home.
Do You Need Emergency Furnace Repair?
If your furnace goes out when it’s dangerously cold, you can call on Great Dane HVAC for emergency furnace repair. However, if you notice your furnace is blowing cool air before a major cold snap and safety doesn’t seem to be a concern, consider contacting us to schedule a regular furnace repair appointment.
