Skip navigation

Serving Northern California Since 1946

Serving Northern California Since 1946


DeHart Plumbing, Heating, and Air Inc. Blog

No, Your Furnace Should NOT Be Blowing Cool Air!


When you bought the furnace, you invested in an appliance that could keep your home warm in the winters. What happens if that furnace starts acting like a second air conditioning unit and blows cold air when you need it to keep the indoor temperatures warm and cozy?

You need to call in professionals to take care of the problem as soon as you can if that happens. Before you call someone, we think that it is important to understand why it is happening. There are several reasons why your furnace might be blowing cold air. We have outlined some of the common reasons for you to help you understand. And if you need anyone to come to look at it, do not hesitate to call us for furnace repair in Modesto, CA.

Why Your Furnace Is Blowing Cold Air

Some of the most common reasons why your furnace is blowing cold air can include:

Thermostat problems

Sometimes, the problem is not in your furnace at all. Your thermostat could be causing problems. If your thermostat is not working properly, it will not send the right signals for your furnace to turn on and off on time and be unable to regulate indoor temperatures.

Make sure you have placed your thermostat away from a heat source. If there is no obvious problem with it, we suggest calling a professional to take a look at it to see if it’s malfunctioning.

Dirty or clogged air filter

A dirty or clogged air filter can cause airflow problems. When airflow to your furnace becomes restricted, the furnace can overheat. Modern furnaces are designed to shut down in case of unsafe temperatures to avoid causing damage. However, the fan from your heat exchanger will continue blowing air, and it will circulate cold air throughout the house.

Broken heating elements

The heating elements inside the furnace can get damaged over time. If the heating elements are broken or malfunctioning, it can cause your furnace to blow cool air instead of heating it up properly before blowing it out.

Ductwork leaks

Another reason your furnace might be blowing cold air is a leak or several leaks in your ductwork. When there are breaches in the ductwork, the warm air can escape from the damaged areas and let outside air in. Most of the air it lets in is colder than the air coming from your furnace, causing the temperatures to drop significantly by the time the air handler distributes the air indoors.

Call A Professional!

If your furnace is no longer blowing warm air and keeping the indoor temperature warm and cozy, we highly recommend calling in an HVAC professional for repairs. Many people try to troubleshoot the problems themselves without realizing what the root cause for their furnace blowing cold air is. If you try to fix it yourself without the proper tools and training, you can risk causing significant damage to the system.

A certified professional has the tools, training, experience, and expertise to safely and adequately recognize and fix the problems in your furnace. At DeHart Plumbing Heating & Air Inc., you get the best professionals in Modesto for your furnace repair needs.

Schedule Service with DeHart Plumbing Heating & Air Inc. Today!

Comments are closed.