Furnace Blowing Cold Air

Cold air through the registers is the fan working while the burner has stopped, and it cools the house faster than doing nothing, so it's worth a call.

Tap to CallNumber arriving soon

When this becomes an emergency

The vents are moving plenty of air and none of it is warm.
The furnace makes a clicking sound repeatedly without any whoosh of ignition following it.
Heat comes on strong for a few minutes, then goes cold while the fan keeps running.
The status light on the furnace is flashing a repeating fault code.

What a pro does

A blinking fault code on the control board is where this usually starts. That code narrows the field fast, and from there a tech verifies whether the ignitor is drawing current, whether the pressure switch closed, whether the inducer motor spun up, and whether the flame is actually being proven once it lights. Newer high-efficiency units in the subdivisions fail differently than mid-century equipment does; a blocked condensate drain or a frosted sidewall intake will lock a modern furnace out cold while an older unit in the same weather just keeps running. Reading the code beats swapping parts on a hunch, and it's free.

Frequently asked questions

What is the flashing light on the furnace trying to say?

It's a diagnostic code, and the legend is usually printed on the inside of the access panel. Counting the blinks before calling gives the tech a real head start.

Can a frozen intake pipe outside cause cold air indoors?

On a high-efficiency furnace, absolutely. If the intake or exhaust termination ices over, the pressure switch won't close and the burner never fires.

Why does the heat quit partway through a cycle?

That pattern usually means the burner lit and then something dropped it out, either a flame-proving fault or a safety limit opening once the unit got warm.

Is a condensate drain really enough to stop a furnace?

Yes, and it's a frequent one. When the drain backs up, a float or pressure switch shuts the burner down deliberately to keep water out of the machine.

Furnace Blowing Cold Air?

Get connected with a local pro now.

Tap to CallNumber arriving soon

Keep going

Heating in North Dakota Boiler Leaking Water Emergency Heating Repair Furnace Making Loud Noise Furnace Short Cycling Heat Pump Frozen Outside No Heat Pilot Light Keeps Going Out Radiators Not Heating Thermostat Not Working

disclaimer: 701 Heating is a free service to assist homeowners in connecting with local service providers. All contractors/providers are independent and 701 Heating does not warrant or guarantee any work performed. It is the responsibility of the homeowner to verify that the hired contractor furnishes the necessary license and insurance required for the work being performed. All persons depicted in a photo or video are actors or models and not contractors listed on 701 Heating.

Same-day and 24/7 emergency services are subject to provider participation, location, technician availability, and demand. Availability is not guaranteed and may vary by market and appointment capacity.

We use cookies and session-based analytics, including session replays (with form inputs masked), to improve this site. See our Privacy Policy.

About · Contact · Privacy · Terms · Disclosure · Sitemap