WE ARE OPEN! All filters are made in the USA in our Alabama warehouse.

Air Filter Discount Codes and Coupons:


Get 5 dollars off your next Filter King order use coupon code: 5off to get $5 off your next order. Click here to see our Filter Sizes.

Get a FREE Coupon Code for ANY Filter in our Entire inventory

Just use code 5off at checkout.

Struggling with your non-standard filter size?

We know how frustrating it can be to find the right fit for your filter.

Especially when your home has a non-standard air filter size.

That’s why we stock over 320 non-standard filter sizes.

But it’s not just that.

When you buy from Filter King, you can know you are buying great quality.

There are so many low-quality filters already on the market. And we didn’t want to add to the problem.

We believe you should have good, clean air in your home — no matter what filter size you have.

And so, along with stocking all kinds of non-standard sizes, we sell only the best and safest quality filters for you and your loved ones.

That way, you can buy with confidence.

And with our easy to use survey tool, you can quickly find the right fit.

What others are saying?

We believe in providing the best product for you.

And we believe every filter buying experience should be:

  • easy to find your size
  • fast delivery to you
  • and kind and respectful to you

But we don’t want you to just take our word for it.

Rebecca, one of our customers who gave us a five-star rating, wrote:

“I received my order very quickly. The owner personally reached out to me to see if I needed any assistance. Our house is up for sale and I will be referring the new owner to Filter King!!”

Andres, another customer, had an issue with his custom order:

“I had some filters customized and were received in no time. Unfortunately, I did have an issue with the measurements so I contacted them. They heard me out and were quick to fix it. This had to be one of the best customer services out there. Without a doubt, great quality/value and I'll be ordering from Filter King again.”

Samuel, who left a five-star review, had been struggling with allergies:

“The filters really filter out everything I need them to. No more runny nose, and sore throat in the morning!”

But beyond odd sizes, what about special cases?

Sometimes, the average isn’t good enough.

Our MERV 13 filters are ideal for anyone with a newborn baby in their house. Because babies are more susceptible to indoor air pollution.

But also, if you have chronic or severe breathing problems, we make filters for you.

This would include:

  • Allergies
  • Asthma
  • COPD
  • Emphysema
  • Chronic bronchitis
  • Lung disease

And anyone in the household who requires the use of an inhaler, oxygen tank, or ventilation machine, would also fall into this category. They are also recommended for people with weakened immune systems who may be affected by airborne pathogens and viruses.

Find Quality Air Filters at the Lowest Price

We offer a ridiculous amount of custom sizes. It’s true.

And that can be overwhelming.

We know.

So we’ve created this super-easy survey tool to guide you through the process.

It’ll only take you a few seconds. Then, you’ll be on your way to a cleaner, healthier air in your home.

Just click here to get started.

And because we don’t want you to miss anything...

Use the coupon code 5off at checkout.