What Does It Mean If a Furnace is Blowing Cold Air?

The furnace in your home should never blow cold air. The purpose of a furnace is to blow hot air throughout your house regardless of the temperature outside. If it is not executing its job correctly, you are encouraged to hire an HVAC professional to take a look at the unit. Here are a few reasons why your furnace might be blowing cold air.

Dirty Filter

Often, the most common reason a furnace blows cold air instead of hot is a dirty filter. Although a heater may seem like old technology, it is actually quite smart. A furnace whose filter is dirty has to work harder. If the unit senses that it is working overtime, the heat exchanger shuts off. If the heat exchanger was to continue running, the entire unit would overheat and stop operating completely, which would require a total replacement.

Thermostat Issues

Whether the thermostat of your furnace is old or the settings are off, it could be causing your furnace to blow cold air. It could even turn out to be that the wrong thermostat was installed on the furnace. An HVAC professional in Kirkland can offer you more guidance.


If the furnace is blowing cold air, you are encouraged to check for leaks in and around the unit. Leaks could mean that the drainage is clogged, causing the rest of the unit to not function as expected.

Gas Oil and Burner

HVAC professionals encourage homeowners to ensure the furnace is receiving regular maintenance. Consistent furnace tune-ups spot potential issues before they become major problems.

Flame Sensor

When cold air is being blown instead of hot, the cause could be a malfunction in the flame sensor. A professional can better diagnose it.

To request more information about a furnace that is blowing cold air, contact Black Lion Heating & Air Conditioning in Kirkland, WA. We provide heating repair, furnace installation, and maintenance, cooling repair and AC maintenance, and electrical services.

Call us today to learn more