Why Is My Furnace Blowing Cold Air?

Keep It Cool: Why Is My AC Running but Not Cooling?
November 25, 2021
emergency heating repair
5 Warning Signs You Need Emergency Heating Repair
December 27, 2021

Why Is My Furnace Blowing Cold Air?

furnace blowing cold air

When winter starts to set in and the cold weather comes, having a working furnace to stay warm is extremely important. In 2015, the Residential Energy Consumption Survey shows that upwards of 118 million American households use a furnace for warmth. With such a high number of citizens using furnaces, heating repair is a constant necessity.

If you’ve woken up to find your furnace blowing cold air, we’re here to help. Here are some of the most common causes that can cause this issue and how to fix them.

Check Furnace Thermostat Settings

Sometimes, you can get lucky and find the issue to be one of the simplest fixes possible. Nearly every furnace will have some sort of heat or thermostat settings that you can check. One of the most common settings is “fan,” which doesn’t produce warm or cold air and only blows air as a fan would.

Check to see if the furnace was accidentally put into this mode. It’s a common mistake for a furnace in fan mode to seem to be blowing cold air since the ambient temperature is much colder in winter. If this is the issue, switch your furnace back to its heating mode and your problem should be over!

Check and Clean Filters

Another highly common issue is that the filters of your furnace need replacing. This is especially common in areas with high dust, dirt, or debris, or in rooms that are dustier than usual. When winter hits, the first thing you’ll want to do is check these filters, even before turning on your furnace.

An overly dirty filter isn’t just inefficient, but dangerous. The lint that these filters catch can become a massive fire hazard. In extreme cases, this lint can ignite and cause a house fire.

Virtually every furnace that blows air will have a filter, so check it often. It’s a good idea to clean it out frequently or to call a heater repair service to do so if you aren’t sure how. 

Inspect Pilot Light

Many furnaces utilize fire to get their heat rather than an electrical heating system. If this is the case, a lack of fire will make it so that there’s no heat at all. 

This fire usually starts with a pilot light, same as in gas grills or ovens. A pilot light is a small flame that will ignite the fuel that the furnace uses, such as oil or gas. 

Inspect this pilot light to make sure that it’s turning on. Consider turning on only the pilot light and not the fuel system to check this. If the pilot light isn’t turning on, you might need to look into HVAC repair.

Still, it could be as simple as replacing the pilot light itself. When in doubt, always call a professional to look into the issue and make the replacement.

Remove Any Blockage

Filters aren’t the only things that get dirty during the lifespan of a furnace. There are many hoses, valves, and other such mechanisms at work in an average HVAC system. Systems that are fully air conditioning units rather than just a heater are especially susceptible to such an issue.

Check all hoses, intakes, exhausts, and everything else on the system for any sort of blockage. Such blockages could be an excess of moisture, a build-up of lint and dirt, and other such issues.

If you aren’t able to access the hoses of your furnace, contacting a heating repair service is the best way to go about this. Likewise, if the blockage is severe, you should leave the repair up to a professional. Cleaning the system without being certain on how to do so can damage or rupture parts of your furnace, rendering it useless.

Refill Fuel

While inspecting your system, everything may seem as if it’s perfectly fine – and it certainly may be. If this is the case, the first thing you should do is check the fuel of the system.

When a furnace runs out of fuel, it simply can’t produce heat, making it so that cold air is all that leaves the system. Depending on your furnace, the fuel could be a number of sources. Look into the specifics of your system to see where and how fuel is added so that you know where you should check.

This is unlikely to be the problem for electrical furnaces, as their fuel is electricity. If your “fuel” is low for an electrical furnace, there is likely an issue with the heating components. For this, you’re looking at an electrical wiring problem, and you’ll definitely want an HVAC repair company for something that complex.

Leaking Ducts

Speaking of rupturing hoses, you can find that one of the reasons you’re dealing with heat blowing cold air is that the warm air can’t make it through. Most furnaces transport hot air through vents and hoses to disperse the air throughout a home.

If these hoses have ruptures or damage in them, they won’t be able to disperse the heat as well. You may feel that there’s still heat coming from your furnace but that it isn’t leaving as well as it could.

When such a problem arises, the first thing you should check is the ducts, hoses, and vents. If these are leaking out the hot air, your furnace is working but with an extreme lack of efficiency. You can sometimes patch up these holes with duct tape and a love for DIY fixes, but contacting heating repair is always a good idea.

Fixing Your Furnace Blowing Cold Air

It’s never good to find your furnace blowing cold air, but it doesn’t always spell disaster. Consider these easy troubleshooting tips to see what’s causing the issue and how you can fix it. When in doubt, always contact professional heating repair services to diagnose and fix the issue.

For more information on heater repair and HVAC systems, feel free to contact us. You can also browse our site for more information.