Shop Furnace and AC Filters - Trusted Filtration Retailer Since 2006

All orders ship for FREE in the United States and Canada! RTF has been In business for 13+ years and is a preferred online retailer for AAF Flanders Furnace and AC Filters. Over 70,000+ filter size combinations available. Get the perfect fit with one of our "exact" size filters.

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Quality Furnace and AC Filters

What’s your need? Commercial? Residential? Industrial? HEPA? We have you covered! At, you’ll find the perfect filter for your HVAC system -- by a leading manufacturer!

Buying filters online at is easy, convenient, and saves you time and money. No high-pressure sales. No time-consuming service appointments. No searching for weeks or months for your filter size. Just friendly, knowledgeable filter experts dedicated to helping you select the right filters for your system.

With thousands of sizes to choose from, you’ll never have to search for your filter again! You can even buy custom furnace and ac filters online! We’ll send you perfect fit filters for your HVAC system. We deliver filters to you for free, too! Whether you live here with us in the Pacific Northwest, or you’re in Texas, Chicago, New York, Los Angeles, or Florida, we deliver for free anywhere in the entire contiguous United States – even oversized or special order filters.

Our Filters

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The benefits of a clean filter

A furnace filter pulls a majority of unwanted particles from your indoor air. Such as mold spores, pet dander, household dust, smoke, pollen, dust ...

More about MERV

Minimum Efficiency Reporting Value, or MERV for short, is a filter rating system devised by ASHRAE, the American Society of Heating, Refrigeration ...

How do I locate my filter?

In many cases if you have never located your heating systems filter it can be a challenge to find it. All systems are different so we will do our v...