Reasons For A Broken or Underperfoming Furnace

Issues with your furnace always come up when you least expect, like in the middle of a frigid day. Since heat has a significant impact on the comfort in your home, it’s important to identify and correct issues with your furnace very fast.

Below are five reasons for a broken or underperforming furnace so that you can quickly determine the proper action to take to get your home comfortable back again.


In case you notice a funny smell from your furnace, or you’re just noticing that something doesn’t feel right with your home’s air quality, a small furnace issue can turn into a major repair very fast. Many homeowners decide to continue to use their furnaces despite obvious problems, but that will only make matters worse later.

While any problem with your furnace should be noted and fixed  quickly, the signs of an underperforming or failing furnace generally are such as:

  • Low heating temperature.
  • Low indoor air quality.
  • Frequent cycling.
  • Irregular airflow.
  • Inconsistent temperatures.

You may also notice that your energy bills has skyrocketed, though there could be more than one cause for that. Tears or leaks in the air duct system, an incompatible thermostat, an incorrect furnace size and poor home insulation are the main causes, but a furnace in need of repair could also be the reason.

Here are the five reasons for a broken or underperforming furnace:


Your furnace is equipped with an air filter that’s designed to stop any dust, pollen and other airborne particulates from circulating in your home, but it also works to ensure your furnace operating efficiently. If a filter becomes dirty enough to stop proper airflow, it could have a major impact on your furnace’s efficiency and operation in a negative way.

Fortunately, this is a simple repair. By inspecting your filter at least once or twice every few months and replacing it as needed, you’ll be able to keep your furnace operating at its optimum level.


While a faulty or a thermostat that is not compatible won’t cause a furnace to stop working, it can impact its ability to operate fully. If your furnace is having problems, checking the thermostat is the quickest and easiest thing to do before find any problems with the other elements that may be causing the issue.


If your furnace has a pilot light or electrical ignition system, it could have a malfunction that affects your unit’s function. If the pilot light or electrical ignition system fails, a gas-fueled furnace can’t ignite the burners and can’t produce heat.

Ideally, your pilot light or electrical ignition system should be checked once a year, along with routine maintenance, to be sure it’s operating properly.


The blower motor, or fan motor, circulates air through your home. If it fails, your furnace will still be able to ignite and work properly, but the blower motor won’t be activated and won’t allow air to circulate through your home.

The blower motor is part of a system of components that work together to circulate the warm air, which includes fan motors, belts and bearings. If there’s a problem with the blower motor, any or all of these components may be the cause. Along with your annual maintenance, your blower motor components should be checked for wear or damage.


Furnaces fueled by natural gas can be impacted by issues with the fuel supply line and an inadequate supply of fuel. Gas is volatile and toxic, however, so any issues with a fuel supply line should be addressed by a professional technician.


If you choose to enjoy the long winter with reliable and consistent heat, it’s much better to prevent furnace issues from coming up at any time.

Furnace maintenance from a professional technician can discover any problems that may cause a broken or underperforming furnace by analyzing each and every component for signs of wear or damage. This not only saves you from inconvenient and unexpected failure in the middle of the busy season, but it also helps you save on serious and expensive repairs in the future.

That’s not all, though. Regular furnace maintenance has other benefits, such as:

  • Lower energy bills: A properly running furnace is more efficient, which means that it requires less energy to keep your home at the temperature you prefer.
  • Extended equipment life: Your furnace is a big investment, but regular maintenance can keep it running properly and help it perform at its best for longer periods of time.

At Denver HVAC Pros, we offer a comprehensive maintenance plan that has its own advantages, such as:

  • 15 percent discount on parts.
  • Guaranteed 24-hour response time.
  • Two complimentary tune-ups, one for your furnace and one for your air conditioning unit, which include a thorough inspection and efficiency analysis prior to the heating and cooling seasons.
  • Filter changes in the spring and fall, as well as email reminders to change your filters during the heating and cooling seasons.
  • Three-year parts warranty on aftermarket parts and a five-year parts warranty on OEM parts installation.
  • 15 percent discount on indoor air quality products and duct cleaning services.


As you can see, there are many possible reasons for furnace problems that can range from a minor inconvenience to a major furnace repair. Fortunately, regularly scheduled maintenance for your furnace can help you prevent these issues before they can inhibit your furnace’s performance in the middle of a cold winter.

If you’re in need of furnace repair or maintenance in your home or business, Denver HVAC Pros can assist. We provide many furnace repair solutions, such as code compliance of systems, carbon monoxide testing, high-efficiency equipment installation and upgraded filtration systems to help your furnace run smoothly and keep you warm and comfortable. Contact us today to schedule an appointment with one of our certified and licensed technicians and keep your home or business warm and safe!

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