How Do I Know When It’s Time to Replace My Furnace Air Filter?

We know that we should check the air filter in our furnace on a regular basis to make sure it’s not too dirty or clogged. During the months when your furnace is running steadily, you may want to change your filter as often as once a month. But sometimes we forget, or our filters get clogged quicker than we expect, so it’s important to know the signs that our furnace air filter needs to be changed.

The Top 3 Signs Your Furnace’s Air Filter Needs to Be Replaced

Your furnace is a magnet for dust and dirt, and when your air filter becomes clogged, it allows debris to accumulate, which can cause a number of different problems for your entire HVAC system. Your furnace air filter works to keep the dust and dirt and debris out of your furnace and ducts, as well as out of the air you breathe. That’s why it’s important to change the filter regularly.

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Filters are not overly expensive and changing them often can prevent more significant damage and repairs in the future, so when in doubt, it’s better to simply replace them. There are several signs that indicate our air filter needs to be replaced:

1 – Your furnace is becoming less efficient, less reliable, or failing completely.

At the very least, if your furnace air filter is clogged with dust and dirt, it won’t be as efficient. Your furnace will have to work harder to circulate the air in your home, causing it to run longer and putting more stress on things like bearings, pumps, fan motors, causing them to wear out sooner. This will lead to increased costs due to repairs and replacements, as well as higher monthly energy bills.

However, if your filter becomes too clogged and airflow is restricted too much, the furnace can fail completely. If your furnace is having trouble starting and staying on, or if you feel like the temperature isn’t proper and consistent even though the furnace is running constantly, it may be time to change your furnace air filter.

2 – The air quality in your home is getting worse and worse.

The air filter in your furnace is designed to clean the air circulating through your house by trapping dust and dirt, pet dander and other allergens, even mould spores and harmful bacteria. Once the filter becomes clogged, it can no longer do its job and allows dirt and dust and debris to pollute the air in your home. This can lead to aggravated allergy and asthma symptoms or other respiratory problems. So if you’re noticing a nagging cough or irritated sinuses that you can’t explain, the air quality in your home may benefit from a new air filter.

3 – Dust and dirt everywhere!

Do you notice a puff of dust coming out of your vents and registers every time your furnace turns on? Is there constantly a layer of dust on surfaces all around your house? Can you see a fuzzy, matted build-up of dirt and debris on your heating vents and registers?

If you’re noticing an abundance of dust gathering on surfaces in your home and you feel like you can never get rid of it, it may be because your furnace is constantly recirculating dust and dirt throughout your home due to a clogged air filter.

Understanding these signs and knowing what to look for when you routinely check you air filter can help you avoid any problems associated with clogged air filters.

It will also help extend the life of your furnace, making it more reliable and efficient. Again, when in doubt, it’s best to simply change the filter. The cost of filters is small compared to the costs of repairs, or even outright replacement of your furnace.

In the months that you’re using your furnace heavily, our experts recommend that you replace your filter every month, especially if you have pets or live in a dry, dusty climate like we do in Alberta.

Keeping an eye on your furnace air filter and changing it on a regular basis is the best way to keep your furnace running reliably and efficiently.

If you feel like you’re constantly changing your air filter, and dust and dirt is constantly built up in your furnace and HVAC system, then it may be time to schedule an appointment for a professional furnace and air duct cleaning service.

Also, we have curated a list of not-so-good furnace noises that indicate something could be wrong. When Your Furnace Talks, Listen: 14 Sounds That Require Attention. 

At Canuck Plumbing and Heating, our experienced and friendly HVAC professionals haven been serving Fort Saskatchewan and the Edmonton area for over 15 years. Whether you’re in need of routine furnace cleaning and maintenance, or an entire furnace replacement, Canuck is here to help!

1 reply
  1. Jeff Madison
    Jeff Madison says:

    I appreciate your tips on how when your furnace is becoming less efficient it should be time to replace your air filter. It seems that if your filter is clogged with dust you would want to get it replaced before things get worse and your air quality gets poorer. My wife and I have been noticing that our furnace isn’t working very well, maybe its time to get serviced.


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