helpful furnace tips

Do-It-Yourself: How to Replace Your Furnace Filter

In the same way that you need to change the oil in your car every 6,000 – 10,000 km to keep it running smoothly, your furnace filters need to be swapped out regularly too. Clogged or old filters are inefficient, can damage your furnace, and even drive up your energy bill as your furnace has to work overtime to do what it needs to.

Luckily, all of this is preventable with a regular filter replacement. Best of all, it’s easy to do yourself. Here are all the tips and tricks you need to know when replacing your furnace filter.

1. Follow the replacement schedule

When it comes to keeping your furnace running optimally and your air clean, regular filter replacement is essential. Changing your filter helps keep your system working more efficiently and for longer. And a more effective system means less need for furnace repairs or furnace replacement.

How to know your furnace filter needs to be changed

There are two types of furnace filters: basic and premium. Basic filters should be changed monthly. Many of the higher-end filters recommend changing every 90 days. If you have pets, a dusty environment, or have just had renovation work done, check your filter more frequently.

You can tell which filter you already have in place by pulling your existing one out to take a look. The premium filters are typically pleated and opaque, the basic are flat and more translucent. 

No matter which type of filter you use, we suggest checking your filter each month just to be sure it’s in good condition. As a general rule of thumb, if the filter is looking grey and dirty it’s time for a new one.

Some other signs that it is time to change your filter include:

  • Energy bills creeping up
  • Increased sickness or allergy symptoms
  • More dust in the air (or collecting on countertops, floor, and furniture)
  • It takes longer to heat your home (due to the short cycling furnace)
  • When in doubt, it’s good to replace the filter
Did you know? Your furnace filter also filters out dust and debris when you are running your air conditioner. Both systems use the same ducting to distribute air throughout your home but air conditioners are even more sensitive to airflow than furnaces. They can freeze up and stop working without adequate airflow. That’s why it’s important to check your furnace filter regularly during the heating AND cooling season.

2. Find the right filter for your furnace and lifestyle

When you walk into the furnace filter aisle in a hardware store, it can be overwhelming to look at all the options available. From the size of the filter and impurities you want to remove, to the price and name brand, there are a lot of things to consider before you head to the check-out aisle. We asked the experts to weigh in on furnace filter selection, and here’s what they had to say.

Choose the right furnace filter size

Yes, different furnaces require different filter sizes, so it’s important that you select the right size for your furnace. Furnace filters are sized by width, length, and thickness. The easiest way to tell is to check the dimensions on the filter that is currently in the furnace before you go shopping.

When it is time to swap out your filters, it’s important to make sure that you’re getting the right size filter for your furnace. To find the size of the filter you need just pull out your existing filter and check along the sides where the dimensions should be listed.

Alternatively, the owner’s manual for your furnace should tell you what size you need. If you can’t find the manual, you can always google your make and model.

Standard-format filters — microparticle rating

Different filters have what’s called a “microparticle rating”. The higher the rating number, the smaller particles can be removed from the air. A basic filter will be a 300 microparticle rating and will remove dust and lint. A midrange filter, at 600 microparticles, will also capture dust mite debris and mold spores. Allergy-rated filters (rated around 1,000 microparticles) will help with pet dander, pollen, and smoke. And the high-end filters, at 1,500 microparticles, can remove bacteria viruses and odors, and maximize the air quality. Naturally, the price goes up when the rating does.

You may be surprised to learn that many professional furnace cleaning companies will recommend a basic filter for most furnaces, as long as it is replaced on a monthly basis!

The reason is that thicker filters with higher ratings tend to clog more quickly, making the furnace work harder, causing a reduction in efficiency and prematurely wearing out parts. The good news is that basic Fibreglass type filters are available at a fraction of the cost, come in bulk quantities and there are several non-brand name options, so it can actually be cheaper to use these filters even with the increased replacement frequency.

It is worth considering higher-end filters if you have allergies, pets, or an older home with mold or mildew issues.

Depending on your lifestyle (pets, dusty hobbies like woodworking, etc.) and your preference, there are different types of filters with varying levels of ability to catch these smaller particles from the air. This can be identified by what’s called a microparticle rating. The higher the rating number, the smaller of particles it can remove from the air. For example, higher range filters (known as allergy-rated filters) can pick up pet dander, pollen, and even smoke and are rated around 1000 microparticles. Your most basic filter, rated at roughly 300 microparticles, will pick up mostly dust and lint. Each filter is priced accordingly, so expect to pay more for the higher number of microparticle ratings.

Large-format filters – MERV rating

For large-format filters (typically 4-6” thick) there’s an entirely different rating system, the most common of which being the MERV (Minimum Efficiency Reporting Value) rating. Filters with a rating between 5 – 8 MERV are equivalent to the filtration a basic standard filter offers and will capture particles 3.0 – 10.0 um (short for tiny particles known as micron’s). A 9-12 MERV rated filter will catch particles as small as 1.0 – 3.0 um and remove 90-98% of particles in the air. 13 – 16 MERV rated filters will capture particles as small 0.3 – 1 um and remove 95- 99% of particles from the air. This level of filtration is equal to what is used in surgical operating rooms. MERV 17 Level filtration is equal to filtration delivered by a HEPA Filtration System. As with standard filters, as MERV rated filters increase infiltration ability, they also increase in price.

How much should a furnace filter cost?

A top-end filter can cost as much as $50/filter. It will last longer, and also provide better filtration. But as we mentioned, for most homes, a basic filter will do just fine. In most cases, you can save money by purchasing a pack of 3 filters versus buying a single filter.

Generic is okay

While there are several different sizes and ratings, there are a number of different brands available on the market. In the end, all that matters is the performance, not the logo.

Don’t forget to double-check that you bought the right one before opening the package so you can return it if you need.

3. Install the new filter

This part might seem easy, but unless you deal with furnaces often (let’s hope not) there are a few important things to remember:

Follow the arrow — When you install your new filter, make sure the airflow arrow (printed on the top or side of the filter) is pointed towards the furnace. This arrow is the direction of air flow.

Don’t force it — As you install your new filter, it should slide in gently and without the need for force. If it feels at all like it’s sticking or difficult to get in, try removing it altogether and doing it again. If you force the filter, it might bend or break.

Re-install the filter cover — You want to keep dust from entering your furnace – and your home. Filter covers are designed to fit over the filter slot to keep everything contained. Most newer furnaces come with filter plate covers to protect you and your furnace. Be sure to put your filter cover back in place once you’ve swapped out your filter. Keep in mind that filter covers are required by most local building codes as they prevent the furnace from drawing air in the furnace room and circulating this air through the house.

4. Set a reminder for next time

Owning a home can involve a regular amount of upkeep, so we recommend setting helpful maintenance reminders for yourself. One of the ways to do this is by writing the date the filter was installed on the side of the furnace filter (permanent markers work well for this). Want to automate it? Set a calendar reminder in your phone for a monthly check-in.

A little care can go a long way

We hope that after reading this article you’re feeling more confident than ever to update your furnace filter. And if this sounds like a lot of work, we’re here to help. Give us a call to schedule your regular furnace upkeep and maintenance.

You can read more about maintaining your furnace in our Homeowner’s Furnace Guide.

Offer Terms: Free Duct Cleaning with Install Financing


Finance your furnace or air conditioner installation with no interest or payments for 6 months, and get a free duct cleaning.

How to get the offer:

  1. Get a free online or in-home quote for A/C installation or Furnace installation from Advanpro.
  2. Apply for financing through Financeit via the Advanpro link: https://www.financeit.ca/s/y2HQMw
  3. Confirm and book your installation with Advanpro, including approved financing.
  4. Ask us to claim and book your free duct cleaning.


Free duct cleaning offer applies to new furnace or air conditioning installations that meet all of the following terms:

  • installation of Lennox furnaces or air conditioners
  • supply and installation fully-financed through a Financeit payment plan with no payments and no interest for 6 months (“6 month deferral”).
  • financing approved and installation booked between March 7, 2022 and June 10, 2022

Duct Work Sanitizing

If you or your loved ones suffer from respiratory issues or allergies, or you’re concerned about the quality of the air that you are breathing, ductwork sanitizing treatments give you the reassurance that your ductwork is sterile and free of contaminants that negatively impact your respiratory and overall health.

Microban is a hospital-grade sanitizing solution, which kills 99.99% of germs, viruses, funguses, molds, and other pathogens.

We also offer Benefect, an all-natural sanitizer made from plant extracts, which also kills 99.99% of germs, viruses, funguses, and molds. ​

Dryer Vent Cleaning

Dryer fires are a top-five cause of house fires. Cleaning your dryer vent regularly greatly reduces the chance of a dryer fire, plus the following benefits:

  • Reduces clothes drying times
  • Lowers utility bills through greater efficiency
  • Extends the life span of your dryer
  • Lessens the amount of allergens in your house

Brush Cleaning Method

Our high-speed rotary brushing equipment sweeps the entire interior surface of your duct work, ensuring that all dust, debris, and pet hair are vacuumed away.

Physically cleaning the entire length of your duct work ensures that no contaminants are left behind, increasing your indoor air quality and peace of mind.

Reverse Octopus Whip Tool

The reverse octopus whip has eight 16” flexible tentacles, which whip around blasting high-pressure air in all directions as it moves through your duct work.

The tool agitates and dislodges the most hard-to-reach dust, debris, and contaminants, moving them toward our duct vacuum for collection and disposal.

Furnace Tune Up

Regular furnace tune ups are essential to maximizing the lifespan and efficiency of your furnace, so you can rely on it to keep you warm all Winter long.​

During our 30+ point inspection, we check all furnace systems to identify components that are worn out and need replacement. Replacing parts before they break — preventative maintenance — maximizes heating efficiency, avoids no-heat emergencies, and saves on costly service calls. 

Home furnaces can last for 20 years or more if well-maintained. A professional furnace tune up every two years helps to preserve your investment for decades.

A/C + High-efficiency Bypass

The secondary heat exchanger in a high-efficiency furnace or A/C coil has delicate, closely spaced fins that must be protected during your furnace and duct cleaning.

For furnaces that require a bypass, we temporarily install a filter above the heat exchanger or A/C coil, and position our duct vacuum above the filter.

This bypass procedure prevents damage by ensuring all dust and debris in your supply duct work is collected before reaching the heat exchanger or A/C coil.

Standard furnaces without A/C don’t have secondary heat exchangers or A/C coils and don’t require the bypass procedure.

Exhaust Flu Stack Cleaning

Mid-efficiency furnaces produce a sand-like, mildly-corrosive byproduct. This substance condenses in the exhaust flu stack and collects over time near the inducer/venter motor, restricting exhaust gas flow. Eventually, it enters the inducer motor and causes premature wear on the furnace.

Exhaust flu stack cleaning removes the build-up to reduce the chance of motor failure and maximize the life span of your furnace. Preventative maintenance ensures your furnace runs efficiently all Winter long — without costly no-heat emergencies. 

HRV Cleaning

In Calgary, all homes built in 2016 or later have a Heat Recovery Ventilator (HRV). Some homes built or renovated after 2013 may also have an HRV.

An HRV efficiently replaces stale indoor air with fresh outdoor air, all year round.

As with any other air-handling equipment in your home, your HRV should be cleaned regularly to ensure the best possible indoor air quality.

Not sure if you have an HRV? Call our team to find out how you can tell.

Furnace Tune Up Checklist


Test & Check

Supply & Service

Measure & Record

A/C Tune Up

Regular preventative maintenance improves efficiency and extends the lifespan of your air conditioning system, with the following benefits:

  • Reduced electricity bills and operating costs. When the unit operates as designed, electricity usage is reduced.
  • Maximized cooling capacity. Home comfort on the hottest of days with minimum run time.
  • Minimized repair bills. Detect and fix small problems before they get worse.

Hot water tank types

Natural draft or atmospheric vented hot water tanks have a 3″ – 4″ steel vent pipe, which runs to a vertical chimney. The chimney is usually shared with standard or mid-efficiency furnaces.

Power vented hot water tanks have one or two black or white plastic vent pipe(s), which are 2″ – 3″ in diameter. The vent pipes usually exit from the side of the house.

Correct furnace sizing guarantee

If the furnace Advanpro installs is determined to be undersized for your home, we will supply and install the correctly-sized furnace at no additional cost.

Advanpro must be immediately notified of any install issues. The guarantee applies for 3 months, starting from the installation date. The guarantee no longer applies if, at any time after the quote or installation, modifications are made to the home that impact heating requirements.

Correct A/C sizing guarantee

If the air conditioner Advanpro installs is determined to be improperly sized for your home, we will supply and install the correctly-sized A/C condenser at no additional cost.

Advanpro must be immediately notified of any install issues. The guarantee applies for 3 months, starting from the installation date. The guarantee no longer applies if, at any time after the quote or installation, modifications are made to the home that impact cooling requirements.

Repair guarantee

If the diagnosed issue is not fixed by our initial repair, we will dispatch the first available service technician to return and fix it at no additional cost.

If we determine that there is an additional unrelated issue, there may be a charge for the additional repair.

Quote guarantee


When we receive an online furnace or air conditioning quote request and the customer accepts the initial quote, we’ll send a comfort advisor to confirm the provided information and quoted price in person.

If the comfort advisor finds any inaccuracies during the in person visit, we’ll revise the quoted price on the spot. After the quoted price is confirmed with an in person visit, the price is set.

If there are unforeseen complications on the date of install, Advanpro will not pass the additional costs along to the customer. (See exceptions in Terms below.)


The guarantee is not valid if the customer provides inaccurate information when Advanpro seeks to confirm any information about the quote. This also applies to the on-site confirmation visit.

In the exceptional circumstance that the chimney liner required for most furnace installations cannot be installed or gets stuck during installation, the guarantee no longer applies and we will provide a supplementary quote to complete installation.

We do not warranty or guarantee customer-supplied thermostats.

Furnace & Duct Cleaning Checklist




Back Skipper Tool

The back skipper is a 1” diameter rounded ball connected to a long, flexible high-pressure airline.

The 1” ball has jets that discharge high-pressure air, pulling the tool and airline through the length of your duct work.

The high-pressure air moves the dust and debris toward our duct vacuum, where it is collected for disposal.​