Home » Blog » Tips » Why Your Heater Would Blow Cold Air

Why Your Heater Would Blow Cold Air

Furnace blowing cold air

In Dallas, homeowners usually rely on electric or natural gas heating systems. However, a few still use oil furnaces, propane, or the more sustainable option of geothermal heat. Another heating option that’s been gaining popularity is heat pumps. It’s important to note that heat pumps produce mild hot air compared to an oil or gas furnace. Understanding the type of heating system you have is the first step in discovering why your heater or furnace is blowing cold air.

Before you contact Lex Air Conditioning & Heating, there are some simple steps you can take to rectify the problems on your own. These could range from simple thermostat adjustments to checking if your filters need to be replaced. After you’ve tried remedying the problem on your own, but your heater still blows cool air, it’s time for a professional touch.

If you’ve tried fixing your furnace and it still isn’t blowing hot air, the Carrollton heating experts at Lex Air are here to help. To schedule a heating service appointment, call (972) 217-8955 today.

Why is my Furnace Blowing Cold Air?

When the temperatures finally drop in Carrollton, and you turn on your heater, you don’t expect to be greeted with a blast of cold air. In this section, our HVAC techs will explain the various reasons that make a heater blow cold air.

From simple fixes like thermostat issues to more complex problems like a malfunctioning heat pump or a clogged filter, understanding these common problems equips you with knowledge but also helps you determine when it’s time to call a professional.

Thermostat Issues

One common reason your heater blows cold air can be related to problems with the thermostat. Below are some things you can check to see if your thermostat is the source of the heater blowing cold air.

Check your thermostat settings to see if it is set to “on” or “auto” mode. When set to “on,” your furnace fan constantly circulates air that’s about room temperature between each heating cycle, which can result in the furnace blowing cold air. Make sure the thermostat fan is set to “auto” for optimal functioning.

The placement of your thermostat also plays a crucial role in heating and cooling your home. If it’s situated in or near a warmer area of your house, like a room with a fireplace, it might only gauge the temperature of that specific area. This can cause the thermostat to misjudge the overall house temperature, causing other rooms to remain cold. A Carrollton HVAC technician might suggest relocating your thermostat to a more central area, such as a hallway, for a more accurate temperature reading.

Another reason your furnace blows cold air is that the thermostat is outdated or malfunctioning, meaning it might be time for a newer thermostat. At Lex Air, we offer a wide variety of smart and programmable thermostats, so you’ll easily be able to find the right fit for your home.

Why Your Heater Would Blow Cold Air

Dirty Air Filter

A common yet often overlooked reason for a furnace blowing cold air is a clogged or dirty air filter. When the air filter becomes too dirty, it restricts airflow to the furnace, obstructing its ability to heat your home effectively. Dirty air filters not only reduce the efficiency of your heating system but can also cause it to circulate cooler air.

Regularly checking and replacing your furnace filter is a simple yet crucial step in maintaining your furnace’s functionality and ensuring a warm and comfortable home environment.

Dirty Flame Detector

One problem that many homeowners overlook when their furnace is blowing cold is checking the flame sensor or flame detector. This sensor plays a major role in your furnace’s operation, detecting whether a flame is present when the gas valve is open.

If the flame sensor becomes coated with residue or dirt, it may fail to detect the flame accurately, causing the furnace burner to shut off as a safety precaution.

No Pilot Light

Pilot lights are another critical component of the heating process. Modern furnaces often use electronic ignition systems, which can fail and prevent the furnace from igniting properly. If your furnace is older and still uses a traditional pilot light, the malfunctioning pilot light can be due to several factors, like a faulty thermocouple, a clogged pilot opening, or issues with the gas supply.

Identifying the cause requires a careful inspection of these components. Before inspecting, find the pilot light assembly and flip the reset switch off. After waiting 10 to 15 minutes, flip the reset switch to pilot. You’ll want to use a match or lighter to light the outgoing gas during this step. When the pilot light is lit, flip the switch to the on position, then restore power to your furnace.

Since pilot light problems can be potentially dangerous, it’s important to contact Lex Air for professional assistance if you don’t feel comfortable checking or re-lighting the pilot light.

Clogged Condensate Lines

In modern high-efficiency furnaces, clogged condensate lines can be a significant reason for the heater blowing cold air. These types of furnaces produce condensation during the heating process. The condensate drain lines run from the furnace’s heat exchanger to a drain pan, where it releases the excess moisture. If these lines become blocked with debris, algae, or mineral deposits, it can lead to improper furnace functioning.

A blocked condensate line may trigger safety switches that shut down the furnace to prevent water overflow or damage to the system. This shutdown results in the furnace ceasing to produce heated air.

Tripped Breaker

When faced with a furnace blowing cold air, a good initial step is to check for a tripped circuit breaker. This could be the reason behind your heater blowing cold air. When the breaker is tripped, the fan might still operate but circulate air without heating it.

To remedy this, unplug any devices or system units on the same circuit and reset the breaker. Then, reactivate your heating system and check if it now blows warm air. If the problem continues, a Carrollton HVAC technician from Lex Air will be happy to help!

Overheated Furnace

When a furnace becomes overheated, it can shut down as a safety precaution, which may result in it blowing cold air. Overheating in furnaces is often caused by restricted airflow due to a clogged air filter, blocked vents, or issues with the internal components like the blower motor.

When the furnace overheats, the built-in safety mechanisms trigger an automatic shutdown to prevent damage or a potential fire hazard. This shutdown can leave you with a furnace that starts up but then quickly blows cold air as the heating element is turned off.

Duct Issues

Warm air produced by your furnace travels through air ducts to reach rooms and areas throughout your home. However, these ducts can suffer from wear and tear, just like any other part of your house, due to the constant changes in air temperature and frequent usage. This wear can lead to leaking ducts, where warm air might escape or become cooler, significantly reducing heating efficiency. Leaky air ducts can also allow cold air from spaces like attics and crawlspaces to seep in through gaps, cracks, or insufficient seals.

Dirty ducts can also lead to heating problems. To ensure optimal function and efficiency of your heating system, it’s important to have a Lex Air technician inspect your ductwork. If we find any issues like leaking or dirty ducts, we can recommend the appropriate services, like air duct cleaning or duct repairs.

Why is my heater blowing cold air

Gas Supply Line Issues

Issues with the gas supply line can be another reason your gas furnace blows cold air. If the gas supply to the furnace is interrupted or inconsistent, it directly impacts its ability to produce heat. If the gas flow to your furnace is obstructed or inconsistent due to issues within the gas supply pipe, this can affect the furnace’s ability to generate heat.

Handling gas supply issues carefully is crucial, as they pose safety risks. For any related concerns, it’s highly recommended to seek assistance from the qualified professionals at Lex Air Conditioning and Heating, who can safely diagnose and repair these problems.

Control Panel Malfunction

A malfunctioning control panel in your furnace can be another reason for blowing cold air. The control panel is the central hub, coordinating the furnace’s operations, including igniting the burners and regulating airflow.

A fault in this furnace control board can lead to improper functioning, such as the furnace not heating correctly or only circulating cold air. Control panel issues can range from electrical problems to faulty wiring or a damaged circuit board.

Heater blowing cold air

Other Reasons Your Heater Would Blow Cold Air

In addition to the more common culprits like dirty filters or gas supply issues, several other factors might cause your heater to blow cold air. These can range from a cracked heat exchanger to a worn-out blower motor or a compromised heating element to a faulty high-limit switch.

Sometimes, the heater might not be properly sized for the space, leading to inefficient heating. External factors like blocked ventilation, poor insulation, or even drastic temperature fluctuations can also impact the heater’s performance.

While many heating issues can be resolved by simply checking the furnace air filter or thermostat, some problems are more complex or hazardous and require the expertise of a professional HVAC technician. No matter what’s behind your heater blowing cold air, the HVAC system experts at Lex Air can handle it.

What To Do If Your Heater is Blowing Cold Air

Cold air coming from your heater can be unsettling, but there are several steps you can take to troubleshoot and potentially resolve the problem.

  • Verify the thermostat is set to heat and not cool or fan.
  • Check furnace air filter.
  • Inspect the pilot light or ignition system in your furnace.
  • Examine any visible ductwork for leaks or blockages.
  • Make sure all vents are open and unobstructed.

If the above steps don’t resolve the problem, it may be time to call an HVAC professional from Lex Air. Issues like a malfunctioning control panel, gas problems, or a faulty blower motor can be dangerous and require the expertise of a qualified HVAC technician.

Remember, regular maintenance can prevent many of these issues, so schedule routine check-ups with a service provider like Lex Air Conditioning and Heating to keep your heating system in top condition.

Carrollton furnace repair

Heating Issues? Call the Carrollton HVAC Pros at Lex Air Conditioning and Heating Today!

If your heater feels more like an air conditioner, it’s time to contact Lex Air Conditioning and Heating. Our experienced HVAC technicians are equipped to handle all your HVAC needs, ensuring your system runs smoothly and efficiently. From routine maintenance to complex repairs, we’re here to provide top-notch service and solutions.

Call Lex Air today at (972) 217-8955, and let us bring the warmth back into your home!

Garage Air Conditioners

Best AC Unit for Garage

In Carrollton, TX, where scorching summer temperatures are the norm and a box fan just doesn’t cut it, keeping your garage comfortable can be challenging.

washing machine leaks

Why is My Washer Leaking?

If you’ve noticed your washing machine leaking, it is incredibly important that you act quickly to prevent potential damage. Leaks can lead to significant water