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The Top 5 Dangers of a Dirty Furnace Filter

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Action Furnace provides top-tier maintenance for heating equipment in Calgary, Red Deer, and Edmonton. Let our team show you why you should never ignore a dirty furnace filter, and how you can take steps to prevent the dangers dirty filters can cause.


Posted by Ryan | September 25, 2023

The filter in your furnace is essential for ensuring clean air and efficient heating. Filters trap dust, dirt, and other airborne particles to provide you with a safe and comfortable living environment. But many homeowners overlook the importance of keeping this filter clean, exposing their families and homes to a range of risks.

In this comprehensive guide, our team at Action Furnace breaks down the top 5 dangers of dirty furnace filters and shows you how proper furnace maintenance can prevent them.

Homeowner experiencing respiratory symptoms from dirty furnace filter

1. Compromised Air Quality

A clogged filter can no longer efficiently remove particles from the air, causing poor air quality in your home. This can result in health symptoms such as headaches, congestion, and eye discomfort. Prolonged exposure to poor air quality can also exacerbate respiratory conditions and allergies. This can put vulnerable individuals like children and the elderly at greater risk.

Regularly replacing your filters can help prevent air quality problems, but some high-quality filters can even improve the air quality in your home. Consider upgrading to ensure that the air you and your family breathe always feels clean and fresh.

Blocked air vent to represent fire hazard in furnace with dirty filter

2. Risk of Furnace Fires

An overly clogged filter can create a severe fire hazard. When airflow is restricted to a critical point in the ductwork, the blocked air can get redirected, which overheats other parts of the system and can eventually ignite debris or other flammable materials inside. This is not only dangerous for your furnace system but also poses a direct threat to the safety of your home and its occupants.

3. Blower Motor Burnout

When a dirty filter impedes airflow, the blower motor has to work extra hard, leading to potential burnout. Replacing a blower motor can be expensive, so this is definitely something you want to avoid. Furthermore, a burned-out blower motor could lead to a complete system failure, disrupting your home’s heating when you need it the most.

Homeowner looking at high energy bill due to furnace with dirty filter

4. Skyrocketing Energy Bills

A furnace operating with a dirty filter consumes more energy because it has to work harder to circulate air. This inefficiency isn’t just detrimental to your wallet; it’s also an unnecessary burden on the electrical grid, contributing to greater energy waste.

5. Increased Maintenance Costs

Failing to replace a dirty filter will speed up the wear and tear on your furnace, leading to more frequent and costly repairs. This lack of basic maintenance not only shortens the lifespan of your furnace but also means you may face uncomfortable periods without heating while waiting for repairs.

Dirty furnace filter next to clean one

Furnace Filter Maintenance Tips

Regular Replacement

To ward off the dangers associated with dirty furnace filters, it’s imperative to replace your filters at least every 3 months. For best results, we recommend cleaning reusable filters or replacing disposable ones each month during the heating season.

Reusable filters can be cleaned with water and a little detergent, whereas disposable filters need to be replaced entirely.

See Also: The True Differences Between Furnace Filters

Annual Heating Tune-Ups

A thorough annual furnace tune-up and duct cleaning are also recommended for optimal performance. Our technicians at Action Furnace have the skill and equipment necessary to verify your furnace’s safety and present you with the most cost-effective options for any repairs it may need.

See Also: Why Is Furnace Maintenance Important?

Particulate matter trapped in furnace filter that needs to be replaced

FAQ about Furnace Filters

What Does a Furnace Filter Catch?

A furnace filter is designed to catch a wide variety of particles including:

  • Dust and dirt
  • Pollen
  • Pet hair and dander
  • Smoke and fumes
  • Leaky duct contaminants
  • Bacteria and viruses
  • Mold spores and mildew

How Do Furnace Filters Get Dirty?

The filter starts to get clogged when it is left unchanged for an extended period. The particles it traps begin to build up, reducing its efficiency and eventually leading to a range of problems, some of which can be severe.

What are the signs that my furnace filter needs changing?

The furnace may start making unusual noises, you might notice uneven heating across rooms, or there could be a noticeable increase in dust and allergens in the air.

Can I clean my furnace filter instead of replacing it?

Some furnace filters are reusable and can be cleaned, but many are disposable and should be replaced. Check the manufacturer’s guidelines for the filters you’re using, or contact Action Furnace to buy new ones that are compatible with your system.

Can a dirty furnace filter affect my air conditioner?

Yes! In central HVAC systems where the furnace and air conditioner share the same filter, a dirty filter can negatively impact the efficiency of your air conditioning unit. If you have a central air conditioner in your home, you’ll also want to replace or clean your filters routinely during the cooling season and schedule yearly AC tune-ups.

Who should I contact for professional furnace maintenance?

Action Furnace has decades of experience providing furnace and AC maintenance to homeowners in Calgary, Edmonton, and Red Deer. Our qualified home comfort specialists are trained internally and via several elite programs to ensure that they always provide you with satisfactory service. Contact us today to ensure that your HVAC system is always ready to serve your home safely and efficiently.

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Written by Ryan Tutak

Ryan is considered one of Calgary's most knowledgeable residential HVAC specialists. Working in the industry for over 12 years, he's helped thousands of homeowners with their heating and cooling systems. Outside of running Calgary's most reputable HVAC business, you can find him on the Golf course practicing his short game or traveling with his family. His main goal is to create a positive collaborative culture, one in which his employees are excited to come in and are motivated to work hard. He spends the majority of his day working directly with Home Comfort Advisors, Service and Maintenance Technicians, and Customer Service Representatives ensuring they are fully prepared to lead the Home Service Industry in Customer Service.

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