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How To Fix A Furnace That Blows Cold Air

Furnace Blowing Cold Air? These Common Issues May be the Reason
Furnace Blowing Cold Air? These Common Issues May be the Reason from www.thinktankhome.com


If you’re facing a chilly situation where your furnace is blowing cold air instead of the warm and cozy air you expect, don’t panic. This common issue can be resolved with a few troubleshooting steps. In this article, we will guide you through the process of fixing a furnace that is blowing cold air.

Check the Thermostat

The first step is to check your thermostat settings. Make sure it is set to “heat” mode and the temperature is set higher than the current room temperature. It’s also important to check if the thermostat is receiving power. Replace the batteries if necessary or ensure it is properly connected to the power source.

Inspect the Air Filter

A clogged or dirty air filter can restrict airflow and cause the furnace to blow cold air. Check the air filter and clean or replace it if it appears dirty. Regularly changing the air filter is essential to ensure efficient operation of your furnace.

Examine the Pilot Light

If you have a gas furnace, check the pilot light. If it’s not lit, relight it according to the manufacturer’s instructions. A pilot light that keeps going out may indicate a faulty thermocouple, which may need to be replaced by a professional.

Inspect the Ignition System

For furnaces with an electronic ignition system, check if it’s functioning properly. If you hear clicking sounds but the burners don’t ignite, there may be an issue with the ignition system. In this case, it’s best to call a licensed technician to diagnose and fix the problem.

Check the Gas Supply

Ensure that the gas supply to your furnace is turned on. If you suspect a gas leak, leave the area immediately and contact your gas utility provider. Safety should always be a top priority when dealing with gas-related issues.

Inspect the Ductwork

Examine the ductwork for any visible leaks or damage. Leaky ducts can cause cold air to enter the system, resulting in a furnace blowing cold air. Seal any leaks or hire a professional to properly seal and insulate the ductwork.

Check the Pilot Burner or Hot Surface Ignitor

If you have an older furnace with a pilot burner, check if it’s clean and properly adjusted. A dirty or misaligned pilot burner can cause the furnace to blow cold air. Newer furnaces may have a hot surface ignitor, which should be inspected for cracks or damage.

Inspect the Blower Motor

A faulty blower motor can prevent warm air from circulating throughout your home. Check if the blower motor is running smoothly and listen for any unusual noises. If you suspect a problem with the blower motor, it’s best to consult a professional HVAC technician.

Call a Professional

If you have followed the troubleshooting steps and your furnace is still blowing cold air, it’s time to call a professional. An experienced HVAC technician can diagnose the issue accurately and recommend the necessary repairs or replacements.


A furnace that blows cold air can be a frustrating problem, especially during the winter months. By following the troubleshooting steps mentioned in this article, you can identify and resolve common issues that cause furnaces to blow cold air. Remember to prioritize safety and consult a professional if needed. Stay warm and cozy!