Win a $20k+ Trip to the
2026 Milan Winter Games!
Shop by
Over 65,000 5-Star Reviews
America’s Best Partner for Replacement Air Filters
Every size, always in stock, shipped for free.
Every equipment brand has a "Filterbuy companion" for every unique size. Start by selecting your brand below to find the perfect match for your system.
I am so grateful to have found a quality air filter that is just the right size!
Catie F.
verified buyerI was extremely pleased with the customer service that I received. I had purchased the wrong size filter and you guys went above and beyond in order to get me the right ones. You’ve got a customer for years to come.
Rigoberto M.
verified buyerAwesome customer service, fast delivery. I will use them whenever I need new filters and will recommend to my friends!
Shirley O.
verified buyer
Pick your delivery schedule
Save 5% off every order
Air filters serve 3 critical roles in your central air system that contribute to the health and comfort of residents and customers.
Regularly replacing your home’s AC or furnace filter can also help keep down energy bills and costs during times of high use.
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.
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.
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:
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
Odors
Airborne viruses
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.
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.
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.
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.
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
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.
