Why is my furnace blowing cold air? Issues & Solutions

Finding yourself shivering in your own home because the furnace is blowing cold air is more than just an inconvenience; it’s a puzzle that needs solving. As a seasoned HVAC Technician at AireEnergy, serving the Greater Vancouver Area, I’m here to guide you through it. Knowing the ‘why’ behind this chilly dilemma is the cornerstone to finding a solution. In this guide, we’ll dissect the inner workings of your furnace, explore common culprits, and arm you with troubleshooting strategies.

The Anatomy of Your Furnace

Your furnace is a complex machine with various components working in harmony to keep your home warm. When one part malfunctions, it can lead to your furnace blowing cold air. Understanding these components—like the thermostat, air filter, and pilot light—can provide valuable insights into what might be going wrong.

Top Reasons Why a Furnace Blows Cold Air

The Usual Suspects

There are several reasons why you might find your furnace blowing cold air, and each comes with its own set of challenges.

Thermostat Settings

Incorrect thermostat settings are often the simplest explanation. Ensure it’s set to “heat” and the fan setting is on “auto,” not “on,” which can cause the furnace to blow cold air when it’s not heating.

Dirty Air Filters

Clogged air filters restrict airflow, causing the furnace to overheat and blow cold air as a safety measure. Regular replacement is crucial.

Pilot Light Outages

If your pilot light goes out, your furnace can’t produce heat. This is a common issue, especially in older models.

Fan Limit Switch Issues

A malfunctioning fan limit switch can cause your furnace to blow cold air by turning on the fan even when the furnace isn’t hot.

Fuel Supply Problems

Insufficient gas supply will prevent the furnace from heating up, leading to your furnace blowing cold air.

How To Troubleshoot A Furnace Blowing Cold Air

DIY Fixes

Before you call in the professionals, there are a few things you can do yourself to resolve the issue of your furnace blowing cold air.

Thermostat Check

Start with the basics. Ensure your thermostat is set correctly. It’s a simple step but often overlooked.

Air Filter Inspection

A dirty air filter can be the culprit. Replace it if it looks clogged or worn out.

Pilot Light

If the pilot light is out, carefully follow the manufacturer’s instructions to relight it.

Fan Limit Switch Test

This is a bit more complicated and may require professional assistance. If you’re comfortable, you can test the fan limit switch using a multimeter.

How To Prevent Your Furnace From Blowing Cold Air

Proactive Measures

Prevention is always better than cure. Here are some tips to prevent your furnace from blowing cold air in the future.

Regular Maintenance

At AireEnergy, we offer annual maintenance packages that include a thorough inspection and cleaning of your furnace. This can prevent many issues, including your furnace blowing cold air.

Air Filter Replacement

We recommend changing your air filter every 3-6 months, depending on usage and air quality.

Annual Inspections

A professional inspection can catch issues before they become major problems, saving you time and money in the long run.

Furnace Blowing Cold Air: Issues and Solutions

In-Depth Look

Let’s delve deeper into some specific issues that could result in your furnace blowing cold air and their corresponding solutions.

Clogged Condensate Lines

Blocked condensate lines can cause your furnace to shut down as a safety measure. Regular cleaning can prevent this issue.

Leaky Air Ducts

Holes or leaks in the ductwork can result in loss of warm air, causing your furnace to blow cold air. Sealing these leaks can improve efficiency.

Damaged Pilot Light

A faulty pilot light can be both inefficient and dangerous. If you suspect this issue, it’s best to call a professional immediately.

Reliable Furnace Repair & Installation Services by AireEnergy

If you’ve tried all the DIY fixes and your furnace is still blowing cold air, it’s time to call in the experts. At AireEnergy, we’re available 24/7, even on holidays, for both installations and repairs. We offer competitive prices and top-notch services, and we even handle rebate filing for our customers in the Greater Vancouver Area.


Understanding why your furnace is blowing cold air is the first step in finding a solution. With this guide, you’re well-equipped to tackle the issue head-on or know when it’s time to call in the professionals. Remember, AireEnergy is always here to help you with your furnace needs.


In this section, we’ll answer all your burning questions about why your furnace might be blowing cold air, from thermostat settings to malfunctioning fan limit switches.

1. Why is my furnace blowing cold air instead of warm air during winter?

This is the most common question we get at AireEnergy. There are multiple reasons why your furnace might be blowing cold air, ranging from incorrect thermostat settings to a malfunctioning flame sensor. It’s essential to diagnose the issue correctly for a proper solution.

2. How can incorrect thermostat settings lead to my furnace blowing cold air?

Believe it or not, the thermostat is often the culprit when your furnace is blowing cold air. Make sure it’s set to “heat” and not “cool,” and double-check the fan settings as well. Sometimes, a simple adjustment is all it takes to resolve the issue.

3. What should I do if my furnace is blowing cold air due to a pilot light outage?

A pilot light outage is a common reason for a furnace blowing cold air, especially in older models. If you’re comfortable doing so, you can try relighting it yourself. Otherwise, it’s best to call professionals like us at AireEnergy for a quick and safe resolution.

4. Can a dirty air filter be the reason my furnace is blowing cold air?

Yes, a dirty or clogged air filter can restrict airflow, causing your furnace to overheat and blow cold air as a safety measure. Regular replacement of the air filter can prevent this issue.

5. How do safety switches contribute to my furnace blowing cold air?

Modern furnaces come equipped with a variety of safety switches designed to shut down the system if something goes wrong. If any of these switches are tripped, your furnace may go into lockout mode, leading to it blowing cold air. It’s best to consult with an expert to diagnose and resolve the issue.

Why Choose AireEnergy for Your Furnace Blowing Cold Air Issues

If you’re tired of dealing with a furnace blowing cold air, especially during those chilly Greater Vancouver winters, AireEnergy is your go-to solution. Why? Because we bring a trifecta of reliability, experience, and affordability to the table.

24/7 Availability

That’s right, we’re available around the clock, even on holidays. So, if your furnace starts blowing cold air in the middle of the night, we’ve got you covered.

Expert Troubleshooting

Our seasoned HVAC technicians are trained to get to the root cause of your furnace blowing cold air. We don’t just fix the problem; we explain it to you, so you’re empowered for the future.

Rebate Handling

Worried about costs? We offer competitive pricing and even handle the rebate filing for you. That means you can avail yourself of substantial rebates without the paperwork headache.

Top-Notch Services

From the moment you call us to the time we complete the job, you’ll experience top-notch service aimed at exceeding your expectations.

So, if you’re in the Greater Vancouver Area and find yourself grappling with a furnace blowing cold air, remember that AireEnergy is just a call away. We’re here to make sure you stay warm, informed, and satisfied.