Why is My Furnace Blowing Cold Air?

As the furnace kicks into action, a blast of cold air may be a big surprise. Before you panic, give the system a few minutes to operate. At times, a system that has been off for a while might move cold air out of the ducts before warmer air follows. If the system continues to move cold air without any temperature change, you will need to do some furnace troubleshooting.

Troubleshooting Steps

Cold air from your ducts could be the result of several possible issues. Check the following:

  • Is cold air coming from the vents when the furnace is off? Leaky ducts could lead to the movement of air when the system isn’t on.
  • Is the thermostat set to call for heat? If your room temperature exceeds the setting, the furnace shouldn’t operate at all. It’s not unusual for children to tamper with controls, and your system may be set for cooling, an issue that can quickly be resolved without calling a professional for heating service.
  • Is your thermostat battery bad? The controls of a system are only as good as their power source, and fresh batteries could resolve the issue.
  • Is your air filter dirty? A dirty filter can lead to a variety of problems, and a replacement is a cheap alternative to a service call.
  • Is your gas supply intact? A utility disruption can prevent your system from heating.
  • Are any fuses off? Interference with the electrical supply to your system can also impact its performance.

Reset Your System

If the most obvious issues aren’t the source of your problem, a final furnace troubleshooting step involves resetting your system. Lower the temperature setting on the thermostat below the room temperature. Disconnect the furnace’s power supply, and wait several minutes before restoring power. Raise the thermostat setting above the recorded temperature. If your system continues to blow cold air, you will need to contact an HVAC professional for furnace repair.

Professional Heating Service for Safety

Heat exchangers, sensors and safety mechanisms can play a part in furnace repair issues. While many homeowners hope for a DIY solution to their system malfunctions, it’s important to keep household safety in mind. A furnace’s combustion activity can pose a serious risk for fire or carbon monoxide poisoning if the unit is not operating correctly. DIY diagnostics of internal components can be inefficient, and costs can mount as parts are purchased without certainty about the source of the issue. An HVAC professional will move through a series of tests based on the symptoms, pinpointing the source of the problem quickly and efficiently. Additionally, your technician will fix the issue while preserving the integrity of safety components.

W A Air Conditioning can assist if you have been unable to resolve your furnace’s cold air problem. We also offer preventive maintenance to fine-tune your system prior to the winter so that you can head off such issues. Contact our Huntsville, TX, office for an appointment today.


January 15, 2014 5:04 pm