Skip navigation

We are hiring. Training available. Great benefits. Apply Now

Serving the Greater Lansing & Grand Rapids Areas


A-1 Mechanical Blog

Why is Your Furnace Blowing Cold Air?


When the temperature drops outside, the last thing you want to deal with is a gas furnace that doesn’t work. We understand the frustration homeowners feel when they have to schedule furnace repairs, which is why we always strive to let homeowners know what they can do to prolong the lives of their furnaces.

In this blog post, the Lansing furnace repair contractors at A-1 Mechanical will go over the reasons why your furnace is blowing cold air so you can keep your home comfortable year-round.


If your furnace is blowing cold air, don’t panic. The solution may be simpler than you think. Before calling a heating and cooling company, check to see that your thermostat is set to “AUTO”. This will be the first thing a furnace repair contractor checks.

Your furnace is designed to kick on once the temperature inside your home drops below the programmed temperature setting. When the thermostat is programmed to “AUTO”, this means the furnace blower will only push air through the vents when the burners are on.

If the thermostat is set to “ON”, the furnace blower will constantly push air through the vents, regardless of whether it’s heated or not. Changing this setting yourself is simple and can save you the cost of having a HVAC repair contractor come out to your home.


You’ll know your furnace has overheated if you notice it blowing hot air, then cold air, before stopping completely. As a safety precaution, your furnace will automatically shut off the burners and continue running air to cool down the unit. Your furnace completely shuts off once it has reached a safe temperature.

A common reason why furnaces overheat is dirty air filters, which block airflow and cause your furnace to work harder to produce the same amount of heated air. If you recognize the signs of an overheated furnace, call a furnace repair company as soon as possible. A dirty air filter is easy and inexpensive to replace compared to having to repair the heat exchanger.


The pilot light is responsible for igniting the gas in your furnace and heating air. However, if the pilot light is out, your furnace will only be able to blow cold air. Each furnace is a little bit different for how to light the pilot. Be sure to check with the manufacturer’s instructions before attempting to light a gas furnace. If the pilot light refuses to stay lit, you’ll need to call a furnace contractor to fix any issues with the thermocouple. While minor issues can be handled by experienced homeowners, you should always call a professional for any residential furnace repairs outside your comfort zone.

The HVAC technicians at A-1 Mechanical want to make sure your HVAC system doesn’t surprise you with sudden costly repairs. If your home could benefit from any of our furnace installation and replacement services or furnace repair services, please contact our Lansing heating and cooling contractors at (517) 272-8629.

Comments are closed.