Flip your old filter over and read the code stamped in the cardboard. If it says FLR06070, you own an American Standard part. If it says BAYFTFR21M, you own the Trane version. I have pulled both out of furnaces that sit two streets apart, and here is the part most people never get told: it is the same filter. Same size, same shape, same slot.
Those two codes describe one 21x27x5 air filter wearing two different labels, because American Standard and Trane build on shared engineering. So before you hunt for an exact brand match, take a breath. You have more options than the label suggests. The spec sheet I keep open for the American Standard 21x27x5 air filters FLR06070 lays out the sizing and rating choices in one place, and the rest of this page shows you why the name on the box should not drive your decision.
TL;DR Quick Answers
Yes. The American Standard FLR06070 and the Trane BAYFTFR21M are the same 21x27x5 media filter sold under two brand labels. Both fit the shared Perfect Fit cabinet, so one correctly sized replacement works in either system. Confirm the actual size and cabinet depth before you order.
- Same filter, two labels: FLR06070 for American Standard, BAYFTFR21M for Trane.
- Nominal 21x27x5, with an actual size of about 20.7 by 26.2 by 5 inches.
- Available in MERV 8, 11, and 13.
- Measure the old filter and the slot depth before buying.
- To match a rating to your home, start with understanding filter ratings.
Top Takeaways
- FLR06070 and BAYFTFR21M name the same 21x27x5 media filter, one for American Standard and one for Trane.
- Both brands use the Perfect Fit cabinet, so one correctly sized filter drops into either system.
- Nominal size reads 21x27x5. The actual filter runs about 20.7 by 26.2 by 5 inches, so measure first.
- You can buy this size in MERV 8, 11, or 13. Pick by allergies, pets, and airflow, not by the brand.
- Staying on top of a steady change schedule protects your air more than any logo on the frame.
- A few simple habits keep your filter performing between replacements.
What These Two Part Numbers Actually Mean
FLR06070 is the number American Standard puts on its 21x27x5 media filter. Trane calls the very same slot BAYFTFR21M. The two are sister brands built on shared engineering, so the cabinet that holds the filter is one design across both lines. That single shared cabinet is the whole reason one replacement fits either system. If you are still choosing the right system for your home, it helps to know this filter size carries across both of those brand lines.
Sizing is where I see people slip. The label says 21x27x5, but that is the nominal name, a rounded number rather than a tape-measure reading. The filter that actually fits this cabinet measures close to 20.7 by 26.2 by 5 inches. Pull the old one, read its printed size, and check the slot depth before you buy a thing. A 5 inch media cabinet will not take a 1 inch panel, and if you want a deeper media option, confirm the housing supports that thickness first.
Rating is your real decision, and it comes down to who lives in your home. This size sells in MERV 8, MERV 11, and MERV 13. I steer most families toward MERV 11, which keeps the air clean without choking airflow. A pleated option that helps trap more household dust suits a typical home, while a higher rating that works to reduce household allergens earns its keep when someone has asthma or a dog sheds through the summer. The fit never changes, because the cabinet never changes.
“In twenty years of pulling filters out of home air handlers, I have never met a system that cared about the brand on the frame. It reads the size and the fit, which is why a correctly sized 21x27x5 works the same whether the label says American Standard or Trane.”
Reliable Places to Check Before You Buy
- EPA, Guide to Air Cleaners and Air Filters in the Home. Plain guidance on picking furnace and HVAC filters and how often to change them.
- U.S. Department of Energy, Air Conditioner Maintenance. How a clean filter protects both airflow and the equipment behind it.
- ENERGY STAR, HVAC Maintenance Checklist. A simple month-by-month routine that keeps a system running efficiently.
- CDC, Improving Air Cleanliness. Federal guidance on raising filter efficiency to MERV 13 or better where your system allows.
- Wikipedia, Minimum Efficiency Reporting Value (MERV). A clear breakdown of what each MERV number captures by particle size.
- Building America Solution Center, High-MERV Filters. A research-backed look at higher-efficiency filters and the pressure they put on a system.
- UF/IFAS Extension, Maintaining Air Conditioners. University extension advice on filters, coils, and seasonal upkeep.
Three Numbers Worth Keeping in Mind
- Americans spend roughly 90% of their time indoors, where some pollutant levels run 2 to 5 times higher than the air outside. U.S. EPA.
- Swapping a dirty, clogged filter for a clean one can cut an air conditioner’s energy use by 5% to 15%. UF/IFAS Extension.
- A MERV 13 filter captures at least 85% of particles in the 1 to 3 micron range. CDC.
My Honest Take
- The brand label is the least important thing about this filter. Get the size and the cabinet depth right and you are done.
- Run an American Standard or a Trane system in this size? Buy whichever correctly sized 21x27x5 filter you can get reliably and on time.
- The change interval beats the logo every time. A clean filter swapped on schedule outperforms a premium one you forget about.
- When you are unsure, measure. Nominal sizing has sent far more people back to the store than any brand mismatch ever has.
- Planning a proper installation? Get the filter slot sized right from the start so future replacements stay simple.
- Some homeowners would rather have a washable alternative they can rinse and reuse instead of replacing on a schedule.
- For a busy house, buying filters in bulk takes the guesswork out of staying on schedule.
Frequently Asked Questions
Is the FLR06070 the same as the BAYFTFR21M?
Yes, for all practical purposes. They are two brand labels for the same 21x27x5 media filter that fits the shared Perfect Fit cabinet American Standard and Trane both use.
What size is a 21x27x5 filter, really?
The nominal name is 21x27x5. The filter itself measures close to 20.7 by 26.2 by 5 inches. Read the printed size on your old filter before you buy.
Which MERV rating should I pick?
A MERV 8 will handle everyday dust. MERV 11 suits most homes with pets or mild allergies, and MERV 13 catches the finest particles for sensitive households. If your old filter lists an FPR number instead, it helps to see how the rating systems compare. The fit stays the same across all three.
Will a thinner 1 inch filter work in this slot?
No. A 5 inch media cabinet needs a 5 inch filter. A thin panel leaves gaps, and unfiltered air slips right past the media. If you only need a basic panel for a different system, a simple one that helps capture common dust works there, just not in this deep cabinet.
How often should I change it?
Most media filters this size run on a 90 day cycle, though pets, allergies, and heavy use shorten that. Check it monthly and swap it when it looks loaded. Keep a spare on the shelf so you always have another replacement option on hand. Some homeowners also pair the system with adding a UV light, and others look into treating air with UV to cut mold and odors between filter changes.
Know Your Numbers Before You Order
Pull your current filter, read the size printed on the frame, and check the cabinet depth so you know exactly what your system takes. With those numbers in hand, you can pick a correctly sized 21x27x5 replacement with full confidence, whatever brand sits on your equipment.
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