Ultimate Air Filters Buying Guide

Air filters are a simple, relatively inexpensive component, yet they're one of the most crucial car parts that keep your car functioning without faults.

Air filters, along with your oil filter, are a common advisory notice on annual motor services. They're not as durable as other car components, such as the brake pads or brake calipers, and failing to change them as required can create multi-system issues.

To help our customers understand air filters and how to buy air filters online, we've created a comprehensive guide that covers everything from how they work to how to select the correct type of air filter.

We'll cover:

• What are air filters?
• How do air filters work?
• Why do they matter?
• How to tell if your air filter needs changing
• Common air filter materials
• The types of air filters available online
• The best air filter brands and options
• How to choose the right air filter
• Frequently asked questions about air filter parts

What Are Air Filters?

Air filters are located between your engine and the air intake system.

The filter is essential for keeping your car's air intake free of debris and impurities that could potentially reach the engine.

For your engine to function efficiently, only clean air should filter with the fuel. High-quality pleated filter mediums ensure only oxygen-rich air enters the combustion chamber, allowing for the optimal air-fuel mixture required for efficient combustion, engine performance, and fuel economy.

Some of the common contaminants that could enter your car's air intake system include:

• Dust
• Dirt
• Pollen
• Bugs
• Leaves

How Do Air Filters Work?

Once you start your car's engine, it's constantly drawing in air from outside, initially through the grille or fender cavity. That part is specifically for trapping big debris and collecting water, preventing it from entering the engine. Some car makes and models have a water trap or a drain, so even splashes of water don't reach the engine.

Before the air reaches the actual air filter, it passes through a pre-filter chamber, also known as an airbox, found on the inlet of most combustion engines. The box is designed to calm the turbulent air and let the big debris settle before it reaches the filter.

A plastic box that calms turbulence and lets heavy particles drop out before the filter. Just slightly ahead is the replaceable air filter cartridge. The outside air passes through the media and traps the particles, and the clean air is distributed between the engine cylinders for combustion.

Common porous air filter materials include:

• Paper
• Foam
• Cotton

These materials are almost always pleated in design to maximize the filter's surface area, meaning they can trap more contaminants.

Why Do They Matter?

The components of your engine are so sensitive to these contaminants. For combustion, air should be as pure and oxygen-rich as possible for sparking and ignition. Most modern cars now have a mass air flow and intake air temperature sensor that sits just beyond the air filter box. If the air filter isn't functioning correctly or becomes blocked, the necessary air can't flow through to the cylinders, and if that triggers the sensor, some modern cars may not start.

More than that, air filters are essential for your engine's health. A dirty or blocked air filter can massively impact the engine's performance. The entire engine system operates with the constant flow of clean air. If there isn't enough air passing through or it's contaminated with particles, your engine will work harder and your fuel will burn faster.

And it's not just performance; contaminants can cause actual engine damage, such as scratches on the cylinder walls or engine bearings. Over time, these can accumulate to premature wear and tear of engine components or even engine failure.

How to Tell if Your Air Filter Needs Changing

If an air filter needs changing or becomes blocked, you might notice the following:

• If the air filter looks dirty or discolored
• Increased fuel consumption
• Slower acceleration
• Reduced power
• Strange engine noises
• The check engine light comes on on your dashboard.

It's easy to check the air filter yourself, even if you have no experience doing so. It's not secured and, once located, simply lifts out. If you open the hood of your car, you'll visibly see the big engine unit, usually in the middle. Next to it, either to the right or to the left (depending on the make or model of your car), is the black plastic housing of the air box. Unclip or unscrew the cover to access the air filter. 

For a visual guide, here's a link to a YouTube video explaining how to locate and inspect a car air filter.

Note: Most air filter boxes will look similar to the one in the video, but always double-check that it is the air filter before removing car components.

Common Air Filter Materials

The type of material used for the air filter can determine its efficiency and lifespan.

Here are the common air filter materials found on most modern cars:

Paper air filters

Also known as cellulose air filters, they're made from cellulose materials that are actually derived from wood pulp. It's a really dense labyrinth of pleated fibers that efficiently traps contaminants whilst still allowing good airflow.

Paper filters are the most inexpensive and common of the three filter material types. The issue is that because they are so dense, and despite the intense pleating creating a greater surface area, the airflow is nothing more than good. Depending on the specific paper material design, they can sometimes actually restrict air flow. And unlike other materials, you often can't clean and reuse paper air filters.

Manufacturers recommend changing paper air filters every 8,000 to 15,000 kilometers.

Cotton gauze air filters

Cotton gauze air filters are one of the more superior filtration designs. They're manufactured for better filtration performance and are far more durable than paper air filters.

They're designed with multiple layers of cotton gauze that's either coated with oil or a synthetic dry. The oiled version is more popular and common, and it only needs replacing every 8,000 kilometers. Synthetic dry gauze air filters need cleaning periodically.

With the oil design, the coated surface efficiently traps particles but maintains better airflow than paper air filters. They are more expensive, but they last longer and perform better for the money. Cotton gauze filters are typical on a variety of vehicles but are more suited for performance models.

Foam air filters

Foam air filters are rarer compared to the other two options, and you don't necessarily find them on cars as much anymore. They're more common in off-road cars and small motors.

That said, some designs wrap foam around the air filter to act as an extra barrier against contaminants. If you typically drive in dusty environments, such as off-roading, foam air filters might be the better option due to their increased filtration capacity for fine particles.

It's generally advised to change foam air filters every 10,000 to 12,000 kilometers or at 12-month intervals.

The Types of Air Filters Available Online

As well as material, there are multiple types of air filters available online:

Flexible panel air filters

You're most likely to find flexible panel air filters on modern cars. Enclosed in a soft, polyurethane frame (hence the flexible name), these air filters are so much easier to install and remove for inspection. The only downside is that, because they're so flexible, the frame is easily damaged if you think the flexibility means strength.

Rigid panel air filters

Rigid panel air filters are the opposite of flexible panel air filters. They're designed with a rigid plastic frame that maintains the shape and performance. There are more components to this type of air filter, as it often comes with a separate gasket to ensure the air filter is sealed correctly.

With this design, they use synthetic media that is better for performance and more durable.

Conical air filters

Conical air filters are far less common than rigid and flexible panel filters. You're more likely to see them in trucks or heavy-duty vehicles. They get their name because of their cone-like shape, and their performance is comparable to flexible panel filters. You'll often find they're designed using the same media and polyurethane compounds.

We wouldn't recommend attempting to install conical air filters yourself. The positioning of the installation has to be precise to ensure correct air filtration.

Round air filters

Round air filters aren't really that common on modern cars—you're more likely to find them on classic cars. They're not the most advanced filter, and the design is simple compared to others. The round shape does produce an even distribution of air to the cylinders, but it doesn't necessarily work wonders for optimizing the airflow.

Radial seal air filters

Radial seal air filters are more unique. They're designed with a distinctive sealing mechanism that's superior at blocking particles from other materials. They're more common on heavy-duty vehicles like trucks. These motors often take in more contamination particles than standard vehicles.

The Best Air Filter Brands and Options

At Parts Avenue, we strive to provide our customers with the best air filter brands on the market. For that reason, we stock only PUR air filters due to their superior filtration capabilities and affordable price.

PUR

PUR air filters are amongst the best on the market from the original equipment-level manufacturers. 

They achieve a 98% filtration rate of all the common contaminants that could enter your car's engine system. Depending on the type of filter, they can also increase the fuel economy by 6% to 11%.

According to PUR data, their premium air filters only need replacing every 40,000 kilometers, so they're far more economical than some online options. The actual lifespan of the air filter depends on how you drive, where you drive, and where you park (if debris is constantly falling or in the air).

How to Choose the Right Air Filter

There are multiple air filter options on the market, so here's how to pick the correct one.

The Parts Avenue Fitment Check tool

The Parts Avenue Fitness Check tool is the best way to see if you're choosing the right air filter for the make, model, and year of your car. It's easy to use and is located on all individual product pages just below the product title.

Consider how you drive.

If you're prone to driving in areas where more dust and debris are naturally in the air or produced, such as off-road, you'll want to consider buying a cotton gauze air filter over a paper one. Or, if you do daily city commuting, the more affordable paper air filter should be fine.

Check for material and shape.

First, you want to make sure your car is compatible with the shape options. Not all air filters fit into every air box. You can find the information you need in your car manual or online using the Parts Avenue Fitment Check tool. The material shouldn't matter as much in terms of whether it fits, but that's why you also need to consider your driving style.

Frequently Asked Questions About Air Filter Parts

How often should you replace your car’s air filter?

How often you should replace your air filter depends on the material and shape. Advice should always be included in the instruction manual of every air filter you buy online, but it's also good to follow the 12-month replacement rule.

What are the signs that your air filter needs changing?

You might start to notice your car isn't as quick to accelerate, seems slow in general, or fuel consumption is increasing. If you remove the filter and check it, you might also notice it's dirty.

Which type of air filter material is best for your vehicle?

The type of air filter material depends on your driving style and where you drive. If you drive in dusty, dirty areas, you'll need a more durable material than the standard paper air filter option.

A premium air filter, such as the PUR air filters online at Parts Avenue, is the type of reliable, high-quality part your car needs. They're relatively inexpensive and give your engine the protection and airflow for improved performance and fuel efficiency.

Start your search today with Parts Avenue, the most-trusted car parts provider in Canada.