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Why Replacement Air Filters

Air filters serve 3 critical roles in your central air system that contribute to the health and comfort of residents and customers.

Air filters remove harmful pollen, dust, dander, smoke. and bacteria, so they don't circulate throughout your home or commercial space from a dirty filter.
New air filters help to prevent mold and mildew from growing in your central air duct system, which can cause other health-related problems.
Replacement air filters help your home heating and cooling (HVAC) system running smoothly, helping to prevent strain and damage on from circulating air through an old, dirty air filter.

Regularly replacing your home’s AC or furnace filter can also help keep down energy bills and costs during times of high use.

Learn more about what air filters do

Air Filter Buying Guide

For new customers or new homeowners, you may need some assistance in ordering replacement filters online. Considerations including air filter dimensions or sizes, minimum efficiency reporting value, and the difference between air/furnace/HVAC/air conditioner filters all play role in finding the right air filter for your residential, commercial, or industrial application.

Read below for a quick guide to buying the right air filter.

see the different types of air filters you can buy

Air filters have different sizes, brands, components, features, MERV ratings, and filter media. To make sure you’re getting the right air filter for your central air system, make sure you know some of the basics:

Filter size or dimensions – replacement air filters can be properly sized by measuring their width, height, and thickness. Most people use the standard size printed on their existing air filter, but you can also measure for your specific air filter’s nominal size and dimensions.
Air filter MERV rating – MERV ratings indicate how much filtering power your air filter has based on the size of particles that it traps (air particles are sized in microns). MERV ratings range between 1 – 20, but most residential air filters are rated between MERV 8 and MERV 13.
Air filter media – Air filter media refers to the type of material used to filter particles out of the air. Most air filters feature fiberglass filters, cotton, polyester, electrostatic, and pleated media filter options that depend on what components you want filtered out of the air, like dust, pollen, allergens, viral particles, odors, and more.

Learn more about different types of air and furnace filters

Know where your air filter is supposed to go.

learn where to put your replacement air filter

Know where you are installing your air filter before you buy a replacement. It can impact what type of air filter you need to buy. Air filters can be changed from behind intake vents (often called air filters or ac filters) or in your central air unit’s furnace box (often referred to as “furnace filters”). There is no difference between “air,” “ac,” and “furnace” filters, however, it’s important to know your specific application before you buy.

Learn the difference between air filters and furnace filters

The Benefit of MERV 13 Rated Filters

MERV 13 rated air filters have the most filtering power and the capability to filter airborne particles down to .3 microns in size. MERV 13 (Platinum) filters are appropriate for most homes and higher rated than most original equipment manufacturer (OEM) products. They block 98% of airborne particles, are comparable to MPR 1500/1900 and FPR 10-rated air filters, and last 3x as long as traditional fiberglass filters.

With a MERV 13 filter, you can filter out a lot of airborne particles, including:

Smoke
Pollen
Pet dander
Bacteria
Mold

Dust Mites
Pet odors
Airborne viruses
Mildew

Learn more about the MERV rating system

why you should buy a MERV 13 rated air filter

Replacement Air Filters for Residential,
Commercial & Industrial Systems

difference in thickness between a standard residential air filter and an industrial strength air filter

Filterbuy provides a wide range of air filter sizes, thicknesses, and MERV ratings so you can find reliable aftermarket air filters for residential use as well as commercial or industrial applications.

Shop Commercial Air Filters

What Are the Best Air Filters?

The answer to what is the “best” air filter depends on what is most important to you. Whether that means cost, efficiency, effectiveness, or size options, Filterbuy has the widest selection of standard air filter sizes, each with MERV rating and ODOR fighting options. We also manufacture custom air filters for our clients, so you will always be able to find a replacement air filter that performs to the highest degree.

Choosing the right air filter comes down to understanding your needs and the right filter to get the job done.

Start growing your air filter knowledge base

there are many different types of air filters to choose from

Air Filters 101

Replacing your air or furnace filter is a simple task that most homeowners can do themselves. Follow these quick tips below to make sure you successfully change your air filters every time.

How Often to Change Your Air Filter

It is widely recommended you change your home’s air filter every 90 days or 3 months. However, if you have a lot of people in the home, pets, or have particularly dusty or dirty air (smokers or undergoing construction), then it is recommended you replace your air filters at a shorter interval between 30 and 60 days.

Learn more about changing your air filter

How Often to Change Your Furnace Filter

Like AC air filters, it is recommended you change your furnace filters every 90 days or 3 months. This applies to standard thickness furnace filters between 1” – 2”. For thicker furnace filters, the replacement interval increases to 9 months for 3” – 4” thick filters and 12 months for 5” thick furnace filters.

Learn more about furnace filter thickness

What Size Filter Do I Need?

When replacing your air filter, most people will find the nominal size or dimensions located on the edge of your current air filter. If you don’t have the previous filter handy, you’ll need to measure your intake vent for the actual size of your air filter.

"Nominal" refers to the product sizing chart that fits into your intake vent. "Actual" size refers to the true measurements of your air filter dimensions, which will be slightly smaller than the intake vent dimensions. When searching for a 16x25x1 air filter, for example, you’ll likely see 15.5" x 24.5" x .75" listed. Nearly all AC filters go by the nominal size, which is the actual size rounded up to the nearest inch.

Quick Measuring for Replacement Filter Size

Using a tape measure, get the length, width, and depth of your filter slot.
The length and width dimensions are interchangeable, though conventionally the first number is the smaller of the two.
For the depth measurement, standard filters are nominally 1” (actual 0.75”), 2” (actual 1.75”), and 4” (actual 3.75”) deep.

Learn more about getting your replacement air filter dimensions below.

Replacing Your Air or Furnace Filter

Once you have a properly sized replacement filter, it’s time to put your new filter in your intake vent. The process is simple. Follow along in our step-by-step replacement video below.

Why Filterbuy?

Buy Air Filters in Bulk

When you buy in bulk, you save more money per air filter.

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Custom Air Filters

We manufacture custom sized air filters to size, MERV rating, and quantity.

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Air Filter Subscription

Never forget to replace your air filters again with our air filter subscription option.

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Get Air Filters Delivered

Ditch the big box store and get high quality air filters delivered right your door.

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Air Filter FAQs

What is the best air filter for my home?

The best air filter depends on size or dimensions, filtration rating (MERV, MPR, FPR), and quality. Our aftermarket filters are more affordable and higher performing than most OEM (original equipment manufacturer) brands

How do I replace my air filter?

Replacing your air filter is as simple as finding the appropriate size, opening your intake vent, and placing your new air filter snugly in its slot. Be sure that your air filter isn’t bending or creasing to get maximum performance. Learn more about replacing your old air filter here.

Are pleated air filters better than fiberglass?

Pleated air filters are so much better than fiberglass, that they are the only type we produce and sell. Our pleated air filters last 3-6 months (depending on the size and the filtration needs of your home) and capture over 85% of air particles in your space. Fiberglass filters, made of spun glass, last an average of 30 days and capture a much smaller percentage of air particles. You may pay more up front for the pleated filter, but it will pay you back in better air quality and less waste.

How often should I change my air or furnace filter?

It is recommended that you replace your air filter every 90 days or 3 months.

What are air filters made of?

Air filters are made primarily of cardboard, supporting wire, and the filter media. Depending on your filter needs, the filter media can be made of many different types of material, including fiberglass, polyester, cotton, and more.

Why does my central air have two filters?

Most central air units have two filters to allow air intake evenly throughout the house. This increases the ability for your HVAC system to circulate air at equal rates throughout your home and increases the amount of filtration.

Where can I buy air filters?

Air filters can be found online and at your local hardware store. For the best results, buy your replacement air filters from a trusted air filter manufacturer like Filterbuy.

What does MERV mean in air filters?

MERV stands for minimum efficiency reporting value, and it is a rating on how much filtration your air filter is capable of. Most air filters have a MERV rating between 1 and 20, with MERV 1 filters only capable of removing larger debris and MERV 20 capable of filtering out microscopic particles such a viruses and bacteria from the air. Filterbuy offers air filters in MERV 8, MERV 11, and MERV 13 ratings.

What’s the difference between air filters, furnace filters and AC filters?

Air filters, furnace filters and AC filters are similar products and the terms are used interchangeably. Aside from size differences, the air filter that goes in the central HVAC unit or your return vents is called an “AC filter” or just “air filter,” and filters that go your furnace unit in your home are called “furnace filters.”

Are pleated air filters better than fiberglass?

Pleated air filters are better than fiberglass air filters. Our pleated air filters last 3-6 months (depending on the size and the filtration needs of your home) and capture over 85% of air particles in your space. Fiberglass filters, made of spun glass, last an average of 30 days, and capture a much smaller percentage of air particles. You may pay more up front for the pleated filter, but it will pay you back in better air quality and less waste.

What air filter ratings do you carry?

We carry of MERV 8, MERV 11, and MERV 13 rated air filters, which trap and block 85% to 98% of particles in the air. We recommend MERV 8 air filters for standard homes and businesses. MERV 11 and 13 air filters offer elevated performance and increased filtration for residents or businesses that need it.

What quantity of air filters can should I buy?

If you are buying air filters in bulk, you have come to the right place. Filterbuy lets you buy any quantity that you need. As a bonus, you can subscribe to get that exact quantity of air filters delivered to your door every month and receive a 5% discount.