The RTF Filtrete FAPF03 Compatible Air Filter is a replacement filter for 3M Filtrete's FAPF03 Air Filter that fits Filtrete's Ultra Clean Air Purifier model FAP03-RS. Pleated filter with a MERV 8 rating. Guaranteed perfect fit to the OEM replacement filters.
Actual Filter Size: 11-5/8x21-1/8x1
This filter is not made by 3M Filtrete.
Store Reviews from Verified Customers
Millions of Filters Sold and Replaced
Thank you to our valued customers for 17+ years in business. RTF is a trusted retailer for leading brands in the indoor air filtration industry. We strive to provide the best service and air filtration products for our valued customers.
Compatible with Furnace, AC and HVAC Systems
The terms furnace filter and air conditioner (AC) filter. Are there really two different filters for the heating, ventilation, and air conditioning (HVAC) system in your home, or are they referring to the same filter? The answer—they are the same! Often times it depends on what part of the county you are in for the term you hear more often.
No Worry Filter Fit Guarantee
At RememberTheFilter.com, we want to make you happy. That’s why we work hard to ensure you’re always 100% completely satisfied with your purchase. And why we have not just one but two guarantees to make sure if you – or we – make a mistake on an order, we’ll do everything possible to make it right!
Improve Energy Efficiency
Save on energy costs and maintenance fees. Replacing your air filters can also improve the lifespan of your HVAC system. Quality filters will capture particles from the air you breathe but also allow air to travel freely through the filter reducing operating costs.
Frequently Asked Questions
Minimum Efficiency Reporting Value (MERV) is a filter industry standard system that rates the overall effectiveness of air filters. Higher value MERV rating equates to finer filtration, meaning fewer dust particles and other airborne contaminants can pass through the filter. Other common ratings found within certain brands and stores includes FPR, MPR. They all follow the same basic principal, the higher the number the greater overall effectiveness of the air filter.
Choosing the correctly sized air filter is important in order to keep air clean in your home. An improperly sized filter may have limited performance. Determining the proper air filter size can be confusing, since filter packages generally display two sets of dimensions. It is important to understand that these dimension sets are the nominal and actual dimensions of the filter, and differences between the two.
The best place to start is our filter search page that can be found at the following link or at the top of every page.
You can search by filter size, part number, model and more.
Tips: When using our search option to locate your filter size especially for Exact Filters® enter the exact size needed in the format shown here.
No spaces, fractions only 1/8, 1/4, 3/8, 1/2, 5/8, 3/4, 7/8.
Most often there will be an arrow on the side of the filter which will indicate which way to insert the filter. The arrow will show which direction the air is to travel through the filter. If there is no arrow the filter can be installed in both directions.
Remember your filter is designed to protect your system first and foremost. Air should be traveling through the filter before your blower and system.
Furnace, AC and HVAC filters are most often measured in inches. A nominal measurement would be a rounded number like 20x25x1, rounded up to the nearest inch. These filters if measured with a tape measure would likely be closer to 19 ½" x 24 ½" x ¾" which would be the actual true exact size.
At RememberTheFilter.com, we want to make you happy. That’s why we work hard to ensure you’re always 100% completely satisfied with your purchase so you never have to return it. However, in the unlikely event you need to, we’re ready to make it right! For more information on the return policy please visit the "Returns" page.
We get it. Measuring your own HVAC system for custom furnace and AC filters can seem a little scary. But fear not! The RememberTheFilter.com team is here to help you succeed! And if you make a mistake, no worries. With our Filter Fit Guarantee, you can’t go wrong!
All filter orders ship for free in the domestic US. Free shipping is available for addresses inside the 48 contiguous states only. Give us a call at 866-469-8556 or send customer service a quick email if you have questions.
All filter orders ship for free out of the production plant nearest you; FL, NY, OK, IL, CA, NC or WA. Current production times can be found on our lead time page. Delivery details will be provided in your confirmation email.
Not all filters we sell are available for subscription. If filters are available for subscription you will see a dropdown box above the add to cart button.
Subscribe, Save, & Breathe. Keep your air fresh by subscribing to the filter that meets your air quality needs. As a member, enjoy our best pricing per filter and get free shipping in the United States.
Save 20% With Auto-Delivery! Never have to remember the filter again. NaturalAire MERV 8, MERV 10 and MERV 13 AC and Furnace Filter options offer the most convenient way to keep up with regular filter replacement. Ensure you're breathing clean air and your HVAC system is working efficiently for as long as possible. No commitment. Cancel at anytime. Always free shipping!
Not all products are available for subscription.
Have an odd size air filter or need the perfect fit?
If you don't see your filter size listed or you're looking for the perfect fit air filter for your HVAC, Furnace or AC system consider having us make them for you. Air will always take the path of least resistance. A high-quality perfect fit filter can keep your air cleaner and healthier by not allowing any air to bypass the filter and back into your indoor air.