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Why My Heater Is Blowing Cold Air

heating system blowing cold air

Many homeowners are plagued by a heater that blows cold air. Most people do not know how to react when this happens and immediately begin searching for furnace repair services in order to stop their furnace from blowing cold air.

However, there are a few reasons that can lead to a heater blowing cold air instead of hot air. If you’re asking, “Why does my heater blow cold air?” keep reading. This article will explain some possible reasons why your heater might be blowing cool air instead of heated air so you can get back to what matters most keeping your family warm!

How a Heater Works: Gas Furnace and Heat Exchanger

The function of a heater is to heat the room it's in by warming up a heat exchanger before blowing hot air throughout the room. The furnace's heat exchanger is designed with metal coils that absorb, store, and transfer heat from one area to another.

When you flip on your heater, electric current runs through the heater's metal coils. This process heats the coils, which begin to emit hot air into your room. You can feel its warmth on your skin or see it as steam leaving an exhaust vent on cold days.

A heater does not work alone. There are actually two systems involved in this process. One system is the heater itself and its associated hardware such as switches, thermostat, wires, etc.

The other heater system is the furnace which houses a gas-powered fan or blower that circulates air throughout your house while blowing out cold air from the heater's heat exchangers to keep it cool enough not to overheat under prolonged use. This allows you to run your heater without having to worry about overheating the unit... if all goes well over time with proper maintenance and care, of course.

Now that we've covered how a heater works in general let's go over a list of common causes for a heater blowing cold air in your house:

Check Thermostat's Fan Setting

When the thermostat settings are incorrect or have been changed, it may require more energy from the heating system in order to function correctly. Checking these settings periodically is important because they can change due to natural wear and tear, which is normal. If you are unsure about your thermostat setting or believe there could be a thermostat problem, it may be best to contact a heater repair service for assessment.

Check Furnace Air Filter

A second reason that your heater might be blowing cold air instead of warm air is due to a faulty furnace air filter. Furnaces fit with a clogged filter or dirty air filter can cause the heater to work overtime in order to compensate for the lack of indoor airflow and waste energy. To fix this issue, clean or replace your furnace filter regularly so you don't need heater repair services in the winter!

Gas Supply Turned Off

One reason that the heater might blow cold air rather than warm could be because the gas line supply has been turned off. This usually happens when something goes wrong with the heater and it breaks. For example, maybe there was a problem with a gas valve, the gas supply pipe, or something else in your furnace broke down. When this happened, whoever installed your heater would have turned off the gas supply for safety purposes while they fixed or replaced the heater with a new one.

Pilot Light is Out

If your heater's pilot light has gone out, then there will be no way for the heater to function properly because there will not be any ignition within the burners. If your heater is blowing cold air, then a simple thing you can check is looking for your pilot lights and if they are lit or not. It's important to keep an eye on this because a heater without a pilot light will not work and may even be a fire hazard!

Thermostat Not Working

A thermostat not working correctly is another reason for a heater to blow cold air instead of warm air. If your thermostat has any abnormalities or problems, it can stop your heater from coming on when necessary, slowing it down or accelerating it too quickly, or regulating the heater improperly. In order to fix this issue, you should contact a professional heater repair service before winter comes back around!

Check Furnace Control Panel

If none of these simple fixes work for you and your heater is still blowing cold air, then you may need to check and assess your heater control panel. The heater control panel (or furnace control panel) regulates all of the heater's functions and should be checked for any errors or malfunctions that may have occurred from time to time.

Furnace is Overheated

A final reason that your heater might be blowing cold air instead of warm air can be because it has been overheated. When a furnace overheats operating at a higher capacity than normal, then it could have become too hot and triggered an emergency shut down in order to prevent any damage to the furnace blower motor. In this case, it may take a few hours before the heater will function correctly again so you should avoid heater repair services in this case.

Clogged Condensate Drain Lines

If the heater has been running overtime due to any of the issues mentioned above, then it can cause condensation to build up within the heater system. If this condensation is not removed from the heater's pipes, then it will ultimately build up until it reaches an area where air cannot flow through. This buildup of debris is called a clog and may be interfering with your heater's ability to function properly. The best way for you to fix this problem is by contacting a heater repair service since they are familiar with heater systems and how to remove condensate line blockages or drain line clogs safely!

Leaky Air Ducts

Are you still asking yourself, “Why is cool air blowing when the heat is on?” One last reason that your heater might be blowing cold air is because of leaking ducts. If you notice any leaks around your heater, then it may be affecting the heater's ability to circulate warm air. It could also be pulling in cold air from other rooms and mixing with the heater's internal temperature so this should be evaluated by a heater repair service as soon as possible!

Is Your Furnace Blowing Cold Air? Call ARS/Rescue Rooter!

As you can see, if you begin to feel cold air blowing from your vents instead of warm, there are several different possibilities that need to be investigated. Call a heater repair service for assistance!

If your heating system is suffering, it's time to call ARS/Rescue Rooter to schedule heating repair. Our HVAC system experts thoroughly inspect this problem in order to identify the source and correct your heating system as soon as possible. When you don't want to settle for chilly air coming out of your furnace when complete comfort is only a phone call or click away, let us help!

To get started, find your nearest ARS/Rescue Rooter location or call 866-399-2885 to book a furnace repair appointment today. We service equipment from York, Lennox, Carrier, and other major brands.

Frequently Asked Questions

Why is my furnace blowing cold air instead of heat, and how can I fix the unit if the pilot light is damaged?

If your furnace isn’t producing heat, your pilot light may be damaged. When working properly, the pilot light ignites the burners to start the heating process. To try to fix this issue yourself, find the pilot light assembly and reset toggle, which is normally located near the bottom of the furnace. Switch off the toggle, wait a few minutes for the excess gas to dissipate, then set the toggle to the “pilot” position. Hold the reset button and use a match to light the pilot again. Once it’s lit, release the button and your furnace should be working as normal.

I don’t have a pilot light. Why is my central heat blowing cold air?

Some furnaces don’t use pilot lights, but rather flame detectors to start heating. Any carbon buildup or dirt on the flame detector means your furnace won’t ignite. Cleaning the flame detector or calling HVAC experts will resolve this problem.

What should I do if my furnace is blowing cold air because of other issues?

Do you wonder, “Why is my gas heater blowing cold air?” There are many other reasons why a furnace might be blowing cold air. One of these is a clogged air filter; replacing it with a clean one can solve the issue. Another is an inadequate supply of gas, which requires a professional HVAC technician to handle. Cracks or holes in your ductwork could be another cause of trouble, and these can be resolved by sealing your ducts. Another simple fix could be to check your thermostat — if it’s set to “on” instead of “auto,” it may only be running the fan and not the heating element.

Searching for more knowledge to boost your indoor comfort? Sign up for our email newsletter and you'll receive expert tips and advice from our HVAC & plumbing pros. Plus when you sign-up. you'll be entered into a drawing to win a FREE 50 Gallon Gas or Electric Water Heater!

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