Is Your HVAC Furnace Overheating? Three Telltale Signs

Dec 27, 2019 | Blog

Your HVAC system’s furnace can become overheated, just like any electrical appliance. This can permanently damage your HVAC system, as well as creating the potential for your home to catch fire. It is imperative that everyone in your household know the three main signs of your furnace overheating to avoid serious trouble and to be able to call for assistance right away:  


1. There is a burning smell when your furnace is running 

 When you on your furnace for the first time for the season when cold weather arrives, there is usually a bit of a burning odor for about a half an hour or so. This is normal. Your HVAC system is being exposed to heat for the first time since last season, and the dust and debris that has accumulated in it is being burned away. You can avoid this by having your HVAC system professionally inspected and cleaned before the start of Winter. This will prevent most of the burning smell. The cleaning will remove the dust and dirt from your furnace and airways. If the burning smell doesn’t go away shortly after you start up your furnace, there may be a serious problem that could become dangerous quickly. Shut off your furnace and call Centerville Heating & Cooling at 937-353-1169 immediately so that we can get one of our trained HVAC technicians to your home right away to check out the situation and make any necessary repairs.  


 2. Your furnace is making odd noises 

There is literally no scenario in which your HVAC system making strange noises is a good thing. When it is working correctly, it will run quietly at all times. Any sound coming from it means that something is not right somewhere. There is one sound in particular that is always a reason for concern, and that is a loud humming sound. This is an indication that the motor is getting overheated and will stop working very soon. The motor can become overheated for a few reasons: 


 • The air filter has become clogged with dirt and debris

 If your furnace’s air filter isn’t changed regularly, it will become clogged and prevent air from being able to flow through freely. Your furnace will become overworked quickly because it will continue to try to force air through the clogged air filter. This will cause the motor to burn up and break. Check your furnace’s air filter once a month during the winter months when your furnace is in frequent use and replace it at least once during the cold-weather season. 


 • The air vents in your home are closed off

 A lot of people shut the air vents in rooms or areas of their homes that are not in regular use, such as spare bedrooms, basements, attics, etc., to cut back on energy use. However, doing this actually causes your furnace to expend even more energy as it works harder to heat your entire home. Your home’s specific heating system is designed to heat an area based on its size; therefore, by closing off the vents to some areas of your home, you are causing your furnace to work even harder as it still tries to heat the amount of space it is designed to heat. This results in “short cycling”, which occurs when your furnace starts and stops more frequently than it is supposed to do as it attempts to heat your entire house.


 • Frequently changing the temperature setting manually

If you are constantly changing the temperature setting on your thermostat, this disrupts the cycles that your furnace is designed to run in. Increasing and decreasing the temperature frequently wears out the furnace’s components quickly. If you change your thermostat’s settings often, do your HVAC system a favor and install a programmable thermostat. They can adjust the temperature setting of your furnace without a great deal of stress on the HVAC system. A programmable thermostat also gives you the convenience of adjusting the temperature in your home when you are not there via an app downloaded onto your smartphone. This can cut down on your energy bills as well since you can decrease the temperature when no one is home or when the weather is mild.     


 3. Your furnace isn’t completing full cycles

 If your furnace begins to run, then shuts off again very quickly, this means that it is overheating. The cycles are being cut short in an attempt to prevent the overheating from happening and potentially damaging your HVAC system. This occurs when the heat exchanger in your furnace gets overheated to a dangerous level. The furnace’s high-limit switch will automatically shut the system off. When this happens, turn off your furnace and call us for assistance right away. One of our HVAC technicians will take a look at your furnace, identify the issue, and proceed with any necessary repairs immediately.    


If you think your HVAC system is overheating or if it is showing signs of not working properly, call Centerville Heating and Cooling at (937) 353-1169 or visit our website at We will have one of our licensed HVAC professionals out to inspect your system right away and make sure everything is in top working order throughout the cold weather months and year-round.