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Welcome to UnitedFilter . 

We offer over 150+ Value Priced Filters!

United Filter ships directly to your home via Canada Post.  

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Replace Your Furnace Filter Today!

 Furnace Filters, HVAC and AC Filters in Canada


To choose a replacement filter you will need to know the size, and or manufacturer. Apart from our unique ability to satisfy customers with their special filter needs, all filters are easily found on this site. Simply search by size, brand or merv rating.

Replacement furnace filters improve your home's energy efficiency, remove airborne particles from indoor air and play a key role in providing a healthy living environment.  
Check out MERV ratings here. Additionally, you can also view our Furnace Filter Quality Ratings Chart.

Popular Furnace Filter Sizes

Effective filtration is important for enhancing the indoor air quality of your home or business. Without it, the indoor air quality could be contaminated with harmful particles that can affect your overall health. You'll get cleaner air and better performance with our pleated filters. We offer a wide choice of hvac and furnace filters for both residential and commercial settings.

Pleated furnace filters available include:  16x20x1 furnace Filterfurnace filters 16x25x1, 20x20x1 furnace filters, 20x25x4 furnace filters18x20x1 furnace filters and many more at competitive prices. 

Furnace Filter Brands



Furnace Filter Sizes

 What You Might Not Know About HVAC Filters

Most people pay little attention to their hvac system. As long as it’s keeping them warm during winter and cool during summer, why worry about it? We get it. Beautiful moldings and casements, or even bigger investments  like new roofing and windows can make a dramatic difference. But there can be real impact with small things, and choosing the right furnace filter is one of them. 

Indoor air quality is important to your health and maintaining your home's hvac system is key. It is important to change your furnace filter regularly.  Though it sounds quite simple, in reality there are numerous furnace filter choices out there. Selecting a incorrect filter can cause more harm to your furnace than good. It could actually result in the furnace breaking down. 

indoor air quality ratings chart for furnace filters - unitedfilter canada

How Does The HVAC System Work?

A conventional furnace sucks air in through its return ducts. The blower fan in your furnace pushes the heated or cooled air through the duct system that branches off throughout the various areas of your home. Thermostat settings determine whether warm, or cool air will be delivered through your ducting.

The  furnace filter peforms a dual function by protecting the blower-fan from airborne debris such as hair, dust and other particles which the return duct sucks in. It also assists in preventing airborne particles from being re-circulated into the home. Many people believe that a furnace filter is made to clean the air in your home, which it does not. This was never the original intent. Under normal operating conditions, it is recommend that you change your furnace filter every three months.  How will forgetting to change your air filter affect you, your family and anyone else who enters your home?

6 Things You Should Know About Air Conditioning To Get The Most Out Of It

MERV Ratings 

MERV stands for Minimum Efficiency Reporting Value. Ratings vary between 1 and 16. As the rating increases, the fewer the number of particles that will be able to pass through the filter media.

Filters with higher ratings may not be the right choice. A filter with a high rating may force your furnace to work harder, become less efficient and cost more costly to operate. A rating between 8 and 11 is sufficient for most homes. To be on the safe side, check with your furnace manufacturer or service technician to determine  the best furnace filters for your system. 

How to Choose the Right Type Of Furnace Filter?

There are 6 types of furnace air filters commonly used in our homes.

✔ Disposable Pleated Furnace Filters

The most widespread furnace filter being used is the disposable-pleated type. These are available in an array of standard ratings, as well as sizes. Pleated furnace filters are made with synthetic material and perform well,  filtering out household allergens and particles. The price of pleated filters varies, depending on size, brand and rating. They should be checked monthly for any blockages and replaced every 90 days. They are economical and can be manufactured from green materials.


Standard Fiberglass Filters

These are the least expensive filters available. They have a "spider-web" like appearance and are typically blue in color. Available in an array of standard sizes and are more delicate, as well as having a lower merv rating than pleated filters. These disposable fiberglass filters must be frequently checked and are often needing to be replaced monthly. 


Washable Reusable Filters

Washable filters are made with either a plastic, or aluminum frame. They can be vacuumed and cleaned with water. Available in an array of sizes, as well as different merv ratings. They're more expensive, but can last for up to five years on average, which would make them a more economical solution. Proper maintenance is required and they should be cleaned every 90 days.

Disposable Electrostatic Filters

This type of filter has electrically charged fibers that catch contaminants as they pass through the media. Good for homes that have pets or tobacco smoke. Check your furnace manual to make sure that your systems is suitable to operate electrostatic filters, safely.


Permanent Electrostic filters

These filters have self charging cotton fibers that attract particles. They have a detachable, machine washable filter that can be re-used for up to 8 years. MERV rating is 8 and priced around $15-20.



High Efficiency Pleated Filters


The pleats are evenly spaced to provide efficient airflow, while capturing airborne particles. The synthetic  material is fixed to a rigid metal grid to keep the pleats in place. The provide excellent durability and are effective in trapping small particles. Good for those who have respiratory problems or looking for overall improved indoor air. 


What are the most common furnace filter sizes?

Furnace filters are sized, based on  depth (thickness), length and height. The most prevalent thickness is around 1 inch, with 4 inch also serving as a popular choice on larger systems. Length and height combos range from 10x10 inches to 30x30 inches. The most common available sizes are 14 x 20 x 1, 16 x 20 x 120 x 25 x 1 16 x 25 x 3 and 24 x 24 x 4. To determine the size of your furnace filter, remove and examine the existing one to be replaced, or refer your furnace manual.