February 12, 2021
Furnace Maintenance in Richardson, TX

It’s no fun when your furnace blows cold air, especially if it’s freezing outside. The cause may be simple, or it may need a technician to resolve the situation. There are several possible reasons why your furnace is blowing cold air.

Furnace Just Turned On

When you first turn on your furnace, it will initially blow cool air before it’s warmed up. You should start feeling warm air after a few minutes. It’s the same thing that happens when you turn on a hot water faucet and only get cold water for a bit.

Incorrect Thermostat Settings

People often forget to switch their thermostat from “COOL” to “HEAT” when they use their furnace for the first time that year. Also, make sure the fan is set to “AUTO” and not “ON.” When set to “ON,” the fan will run regardless of whether or not the furnace is on. This results in cold air blowing when the furnace is off.

Clogged Condensate Line

High-efficiency furnaces have a condensate line that removes moisture from them. The line can become blocked with dirt, dust, mold, or ice. Sometimes the cause is the condensate pump broke. Either of these situations causes cool air to blow.

Hammack Service Company, Inc. in Richardson, TX, can clear condensate lines and replace broken pumps. We’ve been helping people in the greater Richardson area for almost 50 years.

Malfunctioning Furnace Control Panel

There’s a control panel in your furnace that controls its operation. If your furnace is blowing cool air, reset it by turning its power off with its ON/OFF switch. Turn the furnace back on after a few minutes and see if this resolved the problem.


If your furnace overheats, its safety system shuts it down. Furnaces usually overheat because the filter is clogged and needs to be replaced.

Hammack Service Company, Inc. repairs, replaces, and maintains heaters and air conditioners. We also offer indoor air quality and mini-split products and services. When you need a heating or cooling service, please call us.

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