How to Change a Dirty Furnace Filter: A Guide for Homeowners

Are you looking for ways to ensure better air quality for your family? Are you wanting to find ways of lowering your home’s energy bill each month? If so, then you need to learn all that you can about how to change a dirty furnace filter.

Doing so can benefit your home in several ways. Switching it out consistently—ideally once a month—can extend the lifespan of your HVAC system, lower the number of repairs, and improve the air quality in your house.

See below for an in-depth guide on how to change a dirty furnace filter and keep your entire system running smoothly.

Signs You Need to Switch Your Furnace Filter

Perhaps you’re worried that switching out your furnace filter too early will lead you to spend more money than you need. Maybe you’re worried that your filter should be switched out more frequently than most.

Whatever the case might be, several signs indicate when you should switch out your air furnace filters. 

First, make a personal note of how you and your family are feeling. Are you experiencing frequent headaches? Have your allergies been acting up more than usual? If so, then this could mean the air supply in your house has a higher level of dust and allergens due to the inefficient air filter.

Next, pay attention to the performance of your system. If the HVAC system never seems to shut off, it’s because the unit is trying to play catch-up. A dirty furnace filter can impede the airflow from cycling through the system, causing it to work harder to maintain your preferred temperature.

You can also walk up to the registers in your house and feel the airflow. If it feels surprisingly low, it also could be because the filter is too dirty to allow proper airflow.

If you’re experiencing further complications from your system, then be sure to have a local HVAC contractor take a look. You can use our services to request a free quote from our certified local HVAC partners.

Consequences of a Dirty Furnace Filter

Far too many Canadian homeowners neglect their furnaces. They don’t have a way of reminding themselves to switch out the dirty furnace filter each month, and so their unit experiences some drastic complications.

First, to ensure that you’re changing the filter constantly, try attaching it to a monthly task. For example, every month, after you pay your rent/mortgage, immediately go and switch out the furnace filter. This will guarantee that your filter goes no longer than 30 days without being replaced.

If you don’t prioritize it, there could be severe consequences. Due to the dirty filter blocking the airflow, your furnace will be forced to exert more effort. Eventually, the furnace will overheat and experience something known as “short cycling”.

This can affect your energy bill as well. Since the furnace is having to exert more energy, it will eat more energy and cause your bills to skyrocket. 

Simply put: you need to prioritize switching out the filter before it gets too dirty. Otherwise, there will be bigger complications to deal with.

How to Change a Dirty Furnace Filter

Now that you’ve seen the signs and consequences of a dirty air filter, continue reading to learn how to change out a dirty air filter.

Purchase the Correct Air Filter

If you aren’t sure how to figure out what the proper air filter is for your system, you’re not alone. Many homeowners struggle with this issue.

Start by turning off the furnace and finding the air filter, which is generally located either in the furnace itself, in the plenum attached to the furnace, or behind the return grille. Temporarily remove the filter to look at the size. The size will be marked somewhere on the cardboard frame, such as 24x24x1 or 12x12x1. 

Be sure to note that you don’t need to buy the same brand of air filter each time. Just make sure you purchase the correct size.

Switch Out the Filters

You’ll be happy to hear that this is one of the easiest tasks of homeownership. Once you have the correct air filter size, simply unpackage the new one and have it ready to swap.

Turn the HVAC system off so that no unwanted airborne pathogens make their way inside the system while you’re making the switch. 

Take the dirty furnace filter out and put the new furnace filter in its place. Make sure that the airflow arrow on the cardboard frame is pointed towards the inside of the system, in the direction of airflow. This ensures the airflow will go through the system, as intended.

Switch Out the Filter Frequently

Of course, switching out the dirty furnace filter one time won’t do much good. It’s consistently switching them out that’s the key.

As we mentioned earlier, it’s best to attach this task to another monthly task, such as paying your rent or mortgage payment. As soon as you make the payment, immediately switch out the filter.

In no time at all, this task will become like second nature. Simply stock up on 3-packs or 6-packs of the filters at one time and they’ll be readily available at all times.

Switch Out Your Dirty Furnace Filter Often

Now that you have seen an in-depth guide on how to change a dirty furnace filter, be sure to use this information to your advantage.

Looking to learn more? If so, then be sure to read our free guide on the 6 tips for getting the best deal possible on cheap furnaces. You can get free quotes for all your furnace leads through our services.

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