5 Reasons Why Your Furnace Is Blowing Cold Air?

The five most common reasons a furnace may be blowing cold air.

With most of these situations, you can probably correct the problems yourself.

In other instances, though, you’ll need to call for help from an HVAC professional.

Furnace Blowing Cold Air

If you get a blast of cool air when you first turn on the furnace, but after a couple of minutes, the air feels warm, that is nothing to be concerned about.

It’s normal for cool air to emerge from the vents at first because the furnace has to warm up.

Think of it in the same way as turning on a hot water faucet; you’re going to get cold water at first.

The same effect happens with your furnace.

It must push out the cold air from the vents before the warm air can come.

If warm air doesn’t follow after a few minutes, something else might be going on, and that’s time to schedule a service call.

Thermostat Setting

If there’s a constant flow of cool air coming from your furnace, check your thermostat to see if the unit’s fan is set to “on” or “auto.”

Chances are, your thermostat’s fan setting is set to “on,” in which case your furnace blower will constantly run even when your furnace isn’t heating the air.

By switching the thermostat to “auto,” the fan will only blow when the furnace is heating the air.

Flame Sensor

Pilotless ignition furnaces use a flame sensor to keep the furnace burning once it starts.

If the flame sensor is dirty, your furnace will turn on and begin heating but turn cold relatively quickly.

If you’re familiar with furnace components, you can clean the flame sensor yourself, which should restore your furnace’s heating function.

Or, you could enlist the services of an HVAC technician to clean the sensor for you.

Pilot Light

If your gas furnace is older and it’s blowing cold air, chances are its pilot light has gone out.

If you’re comfortable doing so, follow the manufacturer’s instructions for how to re-light it safely.

Alternatively, you can call your local utility company or an HVAC technician to make sure it is lit safely.

Once it’s lit, it may need some routine maintenance from an HVAC professional if it doesn’t stay lit.

There could be a problem with the thermocouple.

It may need to be adjusted or replaced, which is something an HVAC technician can take care of for you.

Air Filter

Dirty air filters are a problem because they limit airflow into your furnace.

Restricted airflow can cause your furnace to run longer to heat your home until it overheats.

When your furnace overheats, you will only get cold air.

The solution is to replace your dirty air filter with a clean one.

Once airflow to the furnace is no longer blocked, your furnace will be less likely to overheat and should function normally.

Still, Having Problems?

If your troubleshooting efforts don’t resolve the issue, something more serious may be going on.

That’s when you should call an HVAC furnace professional to help sort things out.

The cold air coming from your furnace could be due to a malfunctioning circuit board, damaged ductwork, a faulty igniter, or any number of more serious problems.

These are issues your HVAC tech can easily address.

Call us today at Guardian Heating & Air Conditioning to schedule an appointment.