Furnace Filters Delivered Fast & Free To Your Home

Shop Any Size And Quantity

Starting at $16.50. Cancel anytime.

Furnace Filters Delivered Fast & Free To Your Home

Shop Any Size And Quantity

Starting at $16.50. Cancel anytime.

Shop Furnace Filters For Your Home

How it Works



Select the quantity and sizes of the furnace filters that you need.



Pick how often you’d like your air filters delivered. Shipping is free.


Swap out your old HVAC filters with new ones when they’re delivered.

How it Works

How To Shop For Replacement Furnace Filters from FST Filtration

Shop Air Filters

Select your filter size

Select filter quality


“Dust Bunny Blocker”


“Pet Dander Dodger”
Pet Dander


“Covid Buster”
Pet Dander
Cooking Oil

FST Delivers Air Filters Right to Your Door

Discount Replacement Furnace Filters For Your Home

Looking for high quality furnace filters for your home? FST Filtration has you covered! Shop the widest selection of discount HVAC, furnace and AC filters delivered right to your door when you need them. Fast, free shipping on the lowest prices of American made MERV 8, MERV 11 and MERV 13 filters in the sizes and qualities you need.

Shopping for replacement furnace filters at a big box store typically isn’t the most convenient, so we made it easy to find and order the right filter in 5 minutes or less! Plus, you can save 10% on your order by starting a subscription, and you’ll never have to worry about ordering and changing your filters again.

When should I change my furnace filter?

Replacement Air Filters For Your Furnace In Any Size

Experts recommend that your HVAC furnace filters should be replaced every 60-90 days, or more often if you have allergies or if you have children or pets.

Air filters from FST Filtration are made right here in the USA, using pleated media to trap more airborne particles, and rigid frames to keep their shape through humidity and temperature changes.

Improve your indoor air quality, and extend the life of your HVAC system with the best furnace air filters from FSTFiltration.com.

What is the best MERV rating for furnace filters?

MERV 13 Furnace Filter From FST Filtration

If you’re shopping for a replacement furnace filter, one aspect to consider is the filter’s MERV rating. “MERV” stands for “Minimum Efficiency Reporting Value”, which is a fancy way of saying how many particles can pass through the filter.

Common MERV ratings for furnace air filters are MERV 8, MERV 11 and MERV 13. The higher the rating, the more effective the filter will be in improving your indoor air quality since it will capture more particles.

If you have loved ones who suffer from allergies, asthma or other issues, consider shopping for a MERV 11 or MERV 13 replacement HVAC air filter.

General FAQs

A: FST Filtration (fstfiltration.com) is a fast and simple way to order air filters. Just select the size and type of filter you need, and then choose how often you want them delivered to your home. We’ll ship the filters direct to your door, exactly when they need to be replaced. Air filters from FST are a similar or better quality than what you’d find at the big box stores, often at a fraction of the price.

Just visit fstfiltration.com and click “Find Your Filter”.

From there, select your filter size, your desired filter quality, and then choose whether you want to purchase one, or sign up for a subscription.

A: A good rule of thumb is you should change your furnace filter every 60 days. If you have someone in the home with allergies or asthma, have pets, or live in a dusty environment, you may need to change your HVAC filter more often. Also factors like how much you’re using your heating or cooling system, the size of your home and your indoor air quality can determine how often your air filters should be changed.

A: HVAC filters, including furnace and AC filters, cost different amounts depending on the MERV rating and thickness of the filter itself. A thicker air filter has a higher cost, but delivers a better value since you don’t need to change it as often.

A: FSTFiltration.com has a wide variety of replacement furnace air filter sizes, so the right size for you depends on your specific HVAC system.

Take a look at the existing filter inside your system to see what the dimensions are (they’re usually printed on the side of the filter). You can also determine the right size of air filter for your system by looking in your HVAC system’s owners manual.

If you need to measure your existing air filter:

  1. Measure the length (L) and the width (W).
  2. Measure the depth (D).
  3. Now combine these measurements as L x W x D.

Keep in mind that the filter’s true dimensions will be different than the manufacturer’s rounded numbers, which are called “nominal size”. For example, a filter may measure 19.5” x 19.5” x 2.5”, but be rounded by the manufacturer to 20” x 20” x 3”.

Shipping & Orders FAQs

A: Furnace air filters are shipped fast and free, via USPS Priority delivery.

A: We ship from Utah. Depending on your location, your filter should arrive within 2-8 days.

A: Just give us a call at 435-637-3567 and we’ll help find a solution for you.

A: We’ll make it right! Give us a call at 435-637-3567.

A: We don’t accept returns, but we want to make sure that you’re happy. Give us a call at 435-637-3567 with any concerns or questions.

A: Did you receive a 5 inch air filter, but ordered a 4” inch filter? Don’t worry! You probably received an air filter with the “nominal size” label, which is different from the actual size.

Our manufacturer rounds up the last number (thickness). So when you order a 20x25x4 filter for example, what you will receive may actually measure 19-7/8″ x 24-7/8″ x 4-3/8″, but is labeled 20x25x5.

Try installing the filter you receive, but if for some reason it doesn’t fit, no worries! Just call 435-637-3567 and we’ll help you out.

Subscription FAQs

A: Sure! If you have more than one property or home, you can create a subscription for each one. Just log into your account, click on “Subscriptions”, and start a new subscription with your same account.

A: Yes! If you need to change the delivery frequency on your subscription, email us at customerservice@fstsystems.com or call us at 435-637-3567 and we’ll take care of it for you.

A: Absolutely! Just email us at customerservice@fstsystems.com or call us at 435-637-3567 and we’ll take care of it for you.

Don’t just take our word for it! Read real reviews from FST Filtration customers

“I needed a custom size filter that I could not find ANYWHERE!! I checked all the websites and the size I needed was very expensive. FST Filtration gave me two filters at a very low costs and was shipped the next day! The quality of the filter was great and it was a perfect fit. FST has a new life time customer!”

Alyssa D.

I was surprised how fast my new replacement furnace filter arrived! Definitely thought the shopping experience on the website was quick and easy, and the subscription option means I’ll never forget to change my furnace air filter again 🙂

Furnace Filter Review

“I was amazed with how fast my filters were shipped. With shipping always free I thought I was going to wait awhile for them to arrive. I ordered them on a Thursday night and they were shipped that next day and received them the following week.”

Shea T.

“I subscribed to their auto subscription and they ship it right to my doorstep when its time to be changed. Highly recommended to anyone that forgets to change out their furnace filter.”

Marcey W.
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