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Why is My Furnace Not Blowing Hot Air in North York?

reasons why furnace isn't working

HVAC systems are installed in North York homes and commercial buildings to keep people comfortable and ensure the building stays at a constant temperature. But, even with all their technology, sometimes the system will malfunction and start blowing out cold air instead of hot. For most homeowners, this is an inconvenience rather than a dangerous situation. But for people who are in apartments, commercial buildings, or nursing homes, it can be a matter of life and death. So, if you’re asking the question “Why is my furnace not blowing hot air?”, it might be time to call for furnace repair in North York.

While the problem itself varies from system to system, there are a few big warning signs that your furnace is starting to malfunction. For example, if you notice that your energy bills have been steadily increasing, even though you haven’t been using the heat more than usual, it’s a sign that something is wrong. 

Why is My Furnace Not Blowing Hot Air in North York?

The furnace is likely working overtime to compensate for a loss of efficiency, which means higher energy bills for you. A furnace not blowing hot air can also be a fire hazard, so if you notice any strange smells coming from the vents, it’s important to call an HVAC professional right away. If you’re in Richmond Hill, Markham or any of the surrounding areas, let City Energy take a look at your unit. You can book an appointment online here.

In the meantime, here are some of the most common reasons why furnaces stop blowing hot air:

1. Thermostat Issues

A thermostat is a critical component of a heating and cooling system. Without a thermostat, the furnace would not know when to turn it on and off. It plays a big role in regulating the temperature in your home, so if it’s not working properly, neither will your furnace. Some common issues with thermostats include:

The battery is too low or dead: If the battery in your thermostat is low or dead, it won’t be able to send the correct signals to the furnace. As a result, the furnace won’t turn on or off when it should.

The thermostat is not calibrated properly: This seems like a small issue, but it can have a big impact on the furnace. If the thermostat is set too low, the furnace will run continuously to reach the desired temperature. Conversely, the furnace will never turn on if the thermostat is set too high.

The thermostat is damaged: A cracked or broken thermostat can cause many problems. It may not register the temperature correctly, or it may not turn the furnace on at all.

The thermostat is in the wrong location: The thermostat should be placed in a spot where it can get an accurate reading of the temperature in the room. If it’s placed in a too-cold or too-hot spot, it will give the furnace inaccurate information.

thermostats can be the reason your furnace blows cool air


If you suspect that your furnace isn’t working because of a problem with the thermostat, the first thing you should do is check the battery. If it’s dead, replace it and see if that solves the problem. If the battery is fine, try calibrating the thermostat. If that doesn’t work, you may need to call a professional to look at it.

2. Pilot Light Issues

Most furnaces have a pilot light that ignites the gas when the furnace is turned on. The pilot light is usually located near the bottom of the furnace. If it goes out, the furnace won’t be able to turn on. Some common reasons why pilot lights go out are:

The pilot light tube is dirty: Over time, the pilot light tube can become clogged with dirt and debris. When this happens, the pilot light can’t get enough oxygen and will go out.

The thermocouple is damaged: The thermocouple is a sensor that detects whether the pilot light is lit. If it’s damaged, it won’t be able to do its job properly, and the furnace won’t turn on.

There’s a draft: A draft can blow the pilot light out. If you think this might be the problem, try relighting the pilot light and holding a piece of paper near it. If the paper moves, there’s a draft.

pilot light can cause temperature issues with furnace


If your pilot light goes out, you should first clean the pilot light tube. If that doesn’t work, you may need to replace the thermocouple. If there’s a draft, try to find the source and block it off. You may have to call the HVCA technician to take a look at it.

3. Dirty Air Filter

Your furnace has an air filter that catches all the dirt, dust, and other particles that circulate through your home. This helps to keep the furnace clean and running smoothly. But, over time, the air filter can become clogged with all the debris it has caught. When this happens, the furnace has to work harder to draw in air, and that can lead to a loss of efficiency. In some cases, the furnace will overheat and shut down completely.

dirty air filters could cause furnace to malfunction


It’s important to check your furnace’s air filter regularly and replace it when it starts to look dirty. Depending on the type of filter you have, you may need to replace it every few months or so.

4. Problems with the Blower Motor

The blower motor is responsible for circulating air through the furnace and into your home. It’s usually located near the top of the furnace. The main problem with blower motors is that they can overheat and shut down. This usually happens because the motor is overloaded or something is blocking the airflow.


When your blower motor overheats, you should try to clean the furnace and remove any debris that may be blocking the airflow. If that doesn’t work, you may need to replace the motor.

5. Ignition Issues

The ignitor is what starts the furnace when you turn it on. It’s usually located near the bottom of the furnace. It lights the pilot light and allows the gas to flow into the furnace. Some common problems with ignitions include:

  • The ignitor is too weak to light the pilot light
  • The ignitor is dirty and needs to be cleaned
  • The gas valve is defective and needs to be replaced
  • There’s a problem with the electrical connection


If your ignitor is too weak to light the pilot light, you may need to replace it. You can clean it with a soft brush if it’s just dirty, or you can try to fix the electrical connection if that’s the problem. If the gas valve is defective, you’ll need to call a professional to replace it.

6. Burner Issues

The burners produce the flame that heats and circulates the air through your furnace. A typical gas furnace has two burners, but some larger models can have three or four. The most common problems with burners are:

  • The burner is dirty and needs to be cleaned
  • The gas valve is defective and needs to be replaced
  • The ignitor is too weak to light the pilot light
  • There’s a problem with the electrical connection or wiring


Fault burner is a common and easy problem to fix. You can simply clean the burner with a brush or by vacuuming it. You may need to replace the gas valve or ignitor if they are defective. Always consult a professional if you’re unsure how to fix the problem.

7. Leaking Ducts

Ducts are pipes that carry air from the furnace to the different rooms in your home. Over time, these ducts can develop leaks. When that happens, the heated air escapes before it has a chance to reach its destination. As a result, your home will feel colder than usual, and the furnace will have to work harder to heat the home, leading to higher energy bills. 


Check your ductwork for any signs of leaks or damage. If you find any, have them repaired as soon as possible. A professional HVCA contractor can help you with this.

8. The gas supply is shut off 

A furnace requires some kind of fuel to operate, whether it be electricity, oil, or gas. The ability of your furnace to produce heat will be lost if the gas supply is cut off. The most common reason for a gas shut-off is that the pilot light has gone out, and there is no longer a flame to ignite the gas. 


Before you attempt to relight the pilot light, ensure the source of the problem has been fixed. The thermocouple, a sensor that instructs the gas valve when to open and close, may malfunction if the pilot light continues going out. You’ll need to call a professional to take a look at this. Check for electric furnaces to ensure the power is still on and that there hasn’t been a power outage in your area.

Final Thoughts

Maintaining a constant temperature in your home is the key to keeping you and your family safe. It also saves you money on utility bills. Furnaces can help with this, but they need to be properly maintained from time to time to work well and remain efficient. If you have a furnace that isn’t working like it used to, why not check it before calling an HVCA technician? You may be able to find and fix the problem yourself, saving you some time and money. 


Don’t delay calling a professional if your furnace is not working right or if it breaks down. The sooner your furnace is checked out, the better off you will be. It’s always better to be safe than sorry. If you follow the maintenance tips above, you should be able to maintain your furnace successfully and keep it running smoothly. 

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