SKU: 14342389028

JM R-21 Unfaced Fiberglass Batt Insulation – 15 in x 105 in, 76.56 sq ft (2x6 Walls)

Sale price$78.15 Regular price$86.83
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Ships within 48 hours · Estimated delivery Jul 20 - Jul 25

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Description

JM R-21 Unfaced Fiberglass Batt Insulation – 15 in x 105 in, 76.56 sq ft (2x6 Walls)R 21 Unfaced Fiberglass Wall Batts JM R 21 unfaced fiberglass batt insulation is designed to improve thermal performance and help reduce unwanted sound transfer in interior wall cavities. Pre cut batts fit standard 2x6 wood stud walls and can be added to existing insulation where no vapor retarder is desired. Key Features: Thermal + Sound Control: R 21 performance helps manage heat flow while also supporting sound control in wall cavities Unfaced

R-21 Unfaced Fiberglass Wall Batts

JM R-21 unfaced fiberglass batt insulation is designed to improve thermal performance and help reduce unwanted sound transfer in interior wall cavities. Pre-cut batts fit standard 2x6 wood-stud walls and can be added to existing insulation where no vapor retarder is desired.


Key Features:

  • Thermal + Sound Control: R-21 performance helps manage heat flow while also supporting sound control in wall cavities
  • Unfaced Design: No built-in vapor retarder—ideal for adding to existing insulation or assemblies that require separate vapor control
  • Sized for Standard Framing: Pre-cut for 2x6 wood-stud walls with 16-in on-center spacing (15-in wide batts)
  • Easy Press-Fit Installation: Designed to press in place between studs for straightforward DIY or pro installs
  • Durable Fiberglass: Will not rot, mildew, or deteriorate; noncorrosive to pipes, wiring, and metal components

Specifications Table:

Specification Details
Insulation Type Fiberglass
R-Value R-21
R-Value per Inch 3.8182
Width 15 in
Length 105 in
Thickness 5.5 in
Coverage Area 76.56 sq ft
Faced/Unfaced Unfaced
Vapor Retardant No
Sound Barrier Yes
Stud Spacing 16 in
Fits Wall Framing 2x6
Framing Type Wood studs
Formaldehyde Free Yes
ENERGY STAR Certified Yes
GREENGUARD Gold Certified Yes
For Use in Walls Yes
For Use in Basements Yes
For Use in Attics No
For Use in Ceilings No
For Use in Floors No
Package Weight 32.73 lb
Package Count 7
Total Package Quantity 28
Multi-Pack Quantity 4
Package Type Multi-pack
Bag Dimensions (L x W x D) 20 x 20 x 50
Warranty 1-year limited

Frequently Asked Questions (FAQ):

Q: What wall cavities does this insulation fit?
A: It’s sized for 2x6 walls with 16-inch on-center stud spacing (15-inch wide batts).


Q: Does this batt include a vapor barrier?
A: No—this is unfaced insulation and does not include a vapor retarder.


Q: Where can it be used?
A: It’s intended for wall applications and is noted for use in basements; it is not listed for attics, ceilings, or floors on the provided spec sheet.


Q: How much area does one package cover?
A: Coverage is listed as 76.56 sq ft per package.


Q: Is it certified for indoor air quality?
A: It’s listed as GREENGUARD Gold Certified and formaldehyde-free in the provided specifications.


Quiet Luxury, Hidden in the Walls

The most elevated spaces are never just about what you see—they’re about how the room feels. These unfaced R-21 fiberglass batts create a calmer, more temperature-stable backdrop, softening noise and supporting energy-smart comfort without changing your visual palette. Designed to slip cleanly into standard 2x6 wall cavities, they’re a discreet upgrade that lets your finishes—and your life—take center stage. It’s the kind of behind-the-scenes essential that makes everyday living feel undeniably luxe.


Upgrade your 2x6 walls with JM R-21 unfaced fiberglass batts for comfort-forward energy savings and better sound control.

Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
  1. Standard Shipping : 3-10 business days
  • If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
  • Please click here for more details>>> Return & Exchange Policy
SKU: 14342389028

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4.2 ★★★★★
Based on 30 reviews
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Product Reviews
S
Verified Purchase
S
Charlottesville, US
★★★★★ 5
Comparison with POTAUTO filter: Very similar but cheaper
I bought a POTAUTO MAP 1033C and EPAuto CP846 cabin air filter to compare them for use in my 09 Legacy (gen 4). They both seemed comparable and are cheaper than most other, similar filters, though the POTAUTO was and still is ~33% more expensive than the EPAuto. Both seem built well-enough, considering they're only being used as relatively low-flow cabin filters. That said, the EPAuto is slightly better, mainly due to the white trim piece being unattached along one side on the bottom of the POTAUTO filter. Almost certainly nothing that will affect its performance or longevity, but it is interesting considering it's the more expensive of the two. However, it must be kept in mind that this is an incredibly small sample size. In one of my very scientific tests (/s), I held them up side by side and looked through them toward the sun (obviously being careful) to judge thickness/density and uniformity. Neither had any thin spots that I noticed, and they were pretty similar overall. One of them blocked slightly more light than the other, indicating more filtration, but I unfortunately don't remember which one. I feel like it was the EPAuto, but I don't really want to speculate as I could very well be wrong. What I do remember is that the difference was so minor that all else being equal, it wouldn't justify the cost difference between the two. In other words, even if the POTAUTO were the slightly better one, it wouldn't be worth the extra few dollars for the minimal amount of extra filtration. In another test, I compared the filters to each other and the old filter (which I'm pretty sure was OEM, but certainly not a charcoal filter, so it was significantly thinner) by blowing air from a compressor through them. I held the nozzle at roughly the same distance from each on one side of the filters, and I held my other hand at roughly the same distance from each on the other side. The old filter, unsurprisingly, let much more air flow through. Both charcoal filters were much more restrictive due to their extra thickness, leading me to feel much less air coming through. Both were roughly the same. Both filters also held up just fine to the strong blasts of air. I bought a couple other filters that I was going to cut to fit to use one or both with these filters as a pre-filter and/or additional charcoal layer. After the airflow test, I decided against this, as these are a lot more restrictive than OEM already, and I didn't want to push it, since that could at best cause issues with getting good airflow into the car, and at worst could damage the blower. If not for the fact many, many people have been using these and similar filters for a long time without apparent issue caused by this, I would hesitate to even use these. I haven't noticed a decrease in the airflow, but it's doubtful I would since I rarely turn the fan up past the first couple settings (usually have it on the first) if I have it running at all, and I have the center vents pulled out (to access the inside of the dash) which causes the flow at the vents to be reduced slightly. TL;DR - Both the POTAUTO and EPAuto charcoal filters appear to be a good choice, with the EPAuto having a slight edge on build quality (based on my limited sample size of one each) and a cheaper price. Filtration appears to be very similar between the two, certainly not enough of a difference to warrant the extra price for the POTAUTO over the EPAuto. Flow is significantly more restrictive than OEM filter but doesn't appear to be an issue. I give the EPAuto 5 stars and the POTAUTO 4 stars, only because the value of the POTAUTO is a good bit less (very similar or possibly even inferior quality for 33% more money). I can't speak to their longevity or performance, but I don't imagine either should prove to be an issue. -------------------------------------------------- As a side note relating specifically to the Legacy: replacing the cabin filter in this car is a PITA. It's not overly difficult per se, but a serious pain and certainly not something you're going to do when you have a spare few minutes. I'd rate it probably around a 3.5/10 in difficulty and a 7/10 for annoyance. While you can sort of access it by removing the manual compartment, you can't remove the tray through that. So you need to actually take the whole glove box out, which requires removing the side panel, unhooking the string/loop that keeps it from falling all the way down, and removing a few plastic screws, which can be a bit of a pain (and apparently Subaru loves them since they're all over the car). A stubby Philips driver will be helpful. Once you have the glove box out of the way, you have to unscrew several more of those plastic screws to remove the plastic cover between the glove box and the filter. This hole is where you gain access. Be careful when removing the old filter as loose dirt and debris may fall out and make a bit of a mess. You don't really want to get any in the fan below it if you can help it. Reverse the steps to reassemble it, and remember to reattach the string. Getting the glove box back in its track can be a bit of a challenge; in my experience from doing it multiple times I've found you sort of half force it and half don't. That is, it'll likely offer some resistance even if it's lined up, so if you try to baby it you'll probably be there a while, but also play with the alignment a bit to see if you can get it without marring up the tab and the slot on the right side too much. All in all, expect to spend anywhere from 15-45 minutes on this, and make sure you have a standard length as well as a shorter or stubby Philips screwdriver. I have to say, when it comes to air filters, this car is horrible. The air intake filter is a pain to change, too--much worse than most if not all other cars I've done. -------------------------------------------------- Keywords: Subaru Legacy, fourth gen, fourth generation, 4th gen, 4th generation, 03, 04, 05, 06, 07, 08, 09, 2003, 2004, 2005, 2006, 2007, 2008, 2009
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on September 29, 2017
R
Verified Purchase
R
Louisville, US
★★★★★ 5
Good price on the part and 5 min install saved me $35
Fit fine in my 4th gen 4Runner took 5mins to install
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Reviewed in the United States on April 19, 2026
M
Verified Purchase
M. Clark
San Leandro, US
★★★★★ 4
Fit 4runner
Fit my 05 4runner. Good product
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Reviewed in the United States on August 2, 2025
W
Verified Purchase
WTG
Carnegie, US
★★★★★ 5
Great price!
I love that I can order these on Amazon for less than half of what I would pay at the mechanic. They fit perfect, and they're a pretty easy install.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on March 22, 2026
S
Verified Purchase
Sean
Fort Morgan, US
★★★★★ 5
Will buy again!
What a perfect replacement and they fit just right.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on March 12, 2026

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