Rivian Cabin Filter Performance (OEM vs Aftermarket) Engineering Analysis - Impartial 3rd Party Review

[s0ysauce]

Big thanks for the time and effort to put these to the test.

Sponsored

 

[Electron]

There's some nuance here, for sure, but let me try to break down what we saw to answer your questions.

We do not feel the test is flawed in any way given Rivian's filter needs to seal, period. So, we are comparing 1:1. We also tried 'forcing' a seal (it's not standard or best practice, but we wanted to try), by pushing some gasketing material into the outer edges. It didn't improve the performance, which speaks to a more systemic issue.

I also want to be clear that, though I only had a 'new' Rivian OEM and the one in my truck that had just over 16k miles on it, they both exhibited the same behavior. When it comes to filtration and industry standards, there shouldn't be a 'few bad' in the batch, per se. So, I don't think it's a unique issue, that I happened upon one bad filter. Also, you posited something about a looser fit on the OEM filter--I actually believe my test fixture was a tad tighter than Rivian's filter tray. YES, that could've distorted the border /edge in such a way that I induced the warping we couldn't seemingly overcome.

As far as filter performance, you cannot think of filters and filtration as a sieve. I know it LOOKS that way, but for HEPA and ULPA purposes, those particles are sincerely too damned small to be trapped the way you think they do. It's a combination of Coulombs Law and the Brownian Effect that predominantly traps particulate. The follow-on principles are diffusion, interception, and impaction, but they're predominantly driven from the aforementioned. And the particle physics at this level induces turbulence between the fibers that simply disallow for particles of that size to flow linearly (a good thing, as they're then generally rejected back). So, thicker pleating is meaningless. And I do mean meaningless. There's no situation where you add more fibers or layers and get better filtration due to the intention of the system. The system will drive the same amount of airflow through it (as designed) regardless. IF you get to the point where you're physically reducing the flow, you've compromised the system, and then you're not really measuring filtration anymore, because you've actually changed the volumetric input to the system.

IF you want to optimize for better filtration, it's all in the design and engineering of the filtration media itself (type of fibers, packing of fibers, geometry of pleats, number of pleats, sealing surfaces about the edges, adding surface ionization). In fact, counterintuitively, some of the best performing filtration media has the best flow (least amount of restriction). And monitoring backpressure over time is how most clean rooms determine when to replace their filters. It's a whole thing!

Our AE has his pHD in Filtration Engineering from the University of Minnesota. In our industry, UofM is the gold standard de-facto experts on Aerosol, Particulate, and Filtration. If he tells me that a filter isn't following 'best practice,' (IE: rigid boundary about the edges with a proper sealing surface) I believe him! If you really want to dig into it, every year, UofM has an Aerosol and Particulate short course, where for 3 days you can get somewhere around 12 different pHD Professors and their grad students bombarding you with more information you can absorb at once for the low low cost of $2200 It's enlightening!

Thank you for the detailed reply. It all makes sense.

While reading through it, I couldn't help but to think about my homes HVAC filters. We tend to use a higher Merv rated filter during the Allergy season and a lower Merv filter during the winter. The air flow is quite noticeable even between Merv 11 and 13 for example, and the higher rated filters that are more "tightly knitted" definitely gets dirty faster with less filter life for obvious reasons.

When it comes to filtering particulates it's one thing, but when it comes to filtering exhaust fumes that's a totally different category that also plays a large importance in what people want in a car cabin air filter.

As for filtering out and minimizing exhaust fumes, the filter #3 may not excel in that department, which is the other side of the equation for cabin air filters.

Were the carbon beads or cylinder shaped pieces loose in your aftermarket filters? Most are and if you shake them you can hear how loose they are, which leads to the question of their efficiency for addressing exhaust fumes. In my experience they do nothing to address exhaust fumes as the beads are too dense and too lose to handle this task.

Chances are you may notice more exhaust smell in your cabin with filter #3, even though the filtration for particulates have increased some.

If you ever get around to it and by the way I was sincere about the "buy me a beer" button, it would be great to see the test on these two particular filters as they are highly rated and people swear by them in other auto communities. I've been using them for years and they perform better than OEM filters in my opinion. Best of all they a inexpensive as well.

Activated Carbon variant:
https://www.amazon.com/Installer-Champ-Premium-Breathe-Activated/dp/B07663SQXD

and the HEPA variant:

https://www.amazon.com/Spearhead-Breathe-Filtration-Particles-BE-134H/dp/B08ZHH26PN?th=1

Thanks again.

 

[R1Thor]

Thank you for the detailed reply. It all makes sense.

You're welcome and I'm glad it makes sense (that's always the hardest part)!

While reading through it, I couldn't help but to think about my homes HVAC filters. We tend to use a higher Merv rated filter during the Allergy season and a lower Merv filter during the winter. The air flow is quite noticeable even between Merv 11 and 13 for example, and the higher rated filters that are more "tightly knitted" definitely gets dirty faster with less filter life for obvious reasons.

So, the 'easy' way to improve filter efficiency is to improve density of the pleats. You could also improve the overall thickness (or double the layers), but generally (from what I understand). IDEALLY it shouldn't affect the flow rate of your system, as systems are designed to maintain flow (good systems anyway). It may mean more efficiency drop because it does tax the system harder. This is one of the ways that industrial applications decide to swap filters (due to the filters becoming relatively challenged with built up particulate--which can also improve efficiency of filtration). Also to note: you're generally going to see that filters are optimized for the systems they're installed to: that is, they are effective in certain flow rates. In other words: you can't cut up an HVAC filter meant for home and install it in your vehicle and expect the same performance. They're engineered per use case and have different standards and requirements to meet.

When it comes to filtering particulates it's one thing, but when it comes to filtering exhaust fumes that's a totally different category that also plays a large importance in what people want in a car cabin air filter.

As for filtering out and minimizing exhaust fumes, the filter #3 may not excel in that department, which is the other side of the equation for cabin air filters. Were the carbon beads or cylinder shaped pieces loose in your aftermarket filters? Most are and if you shake them you can hear how loose they are, which leads to the question of their efficiency for addressing exhaust fumes.

Changes are you may notice more exhaust smell in your cabin with filter #3, even though the filtration for particulates have increased some.

So, I do owe a correction and apology to this, for a comment I'd initially made on Every Amp's initial post (more on that in a moment).

For the most part HEPA through ULPA filters are both compliance and regulatory controlled and fully capable of managing particulate 0.3 microns or larger. And most (tracked/traceable/regulated) particulate that we've historically 'cared' about from a health and safety perspective fall inside of that number (my hypothesis being it was VERILY hard to measure anything below that, but that's a complete aside). I cannot speak intelligently to this, but I am aware that there is emerging research suggesting we really need to look at even smaller particulates (and one of the most concerning particulate emissions are closer to .05 microns, which is found within diesel emissions especially). As these likely have health affects we're blissfully ignorant of. <Another reason to buy a Rivian!!>

A lot of those are thought to be, and experimentally demonstrated to be captured by activated carbon/charcoal. I am not learned in this, but my AE did correct me when I brought this up, especially as most VOCs that emit odors ARE seemingly captured in activated carbon. This is why this type of filter seems to allow less 'smells' through. It's not necessarily trapping allergens, but it's definitely trapping aromatics, which also make up VOCs and therefore we can extrapolate also likely entrap most VOCs (more studies required).

I did mention that I thought this might be silly marketing in the post I initially, and prematurely, opined about on Every Amps post. I do apologize for my lack of understanding in this arena. I'm learning along with all of you Bottom line: I do think the activated carbon can be a good thing, and likely is (assuming it's not doing anything to restrict airflow in its application--I did prove that it is seemingly no significant impact in our testing).

If you ever get around to it and by the way I was sincere about the "buy me a beer" button, it would be great to see the test on these two particular filters as they are highly rated and people swear by them in other auto communities. I've been using them for years and they perform better than OEM filters in my opinion. Best of all they a inexpensive as well.

Activated Carbon variant:
https://www.amazon.com/Installer-Champ-Premium-Breathe-Activated/dp/B07663SQXD

and the HEPA variant:

https://www.amazon.com/Spearhead-Breathe-Filtration-Particles-BE-134H/dp/B08ZHH26PN?th=1

Thanks again.

I dig where your head's at. I may be able to evaluate these or similar filters in the future. It's not as cut and dry as neither of these are the exact same form factor (size and envelope geometry) of the Rivian Cabin filters, so I'd have to fabricate new jigs for them, and then go through the same rigor to seal those from leaks that could skew the data.

I have a lot going on in my personal life at the moment, so I'm not going to commit to any of that right now, but it's not off the table, as my scientific curiosity is in full vigor. This is the stuff that gets me up in the morning, because nerd


Thanks for nerding out with me, @Electron and Rivian Forums !!

 

[R1Thor]

For fun, here's some presented data from my Aerosol and Particulate course texts that help enlighten particulate behavior relevant to Filtration Engineering:

Keep in mind that fiber density, layers, pleating, and media fiber type (along with other engineered variables, such as surface treatment and ionization) are engineered with respect to the application they're used in.

So, to emphasize: a clean room filter is different than a PAPR filter is different from an N95 mask, is different from our cabin air filters...even though they're essentially tasked with doing the same thing--keeping our breathable air safe in these environments! And so much is taken into consideration for Engineering such things that appear very minor (and are taken for granted in our daily lives) to do that.

It's one of the big reasons I'm happy doing what I do for a living. I do feel as though what I do makes a difference, as my work certifies the companies are performing as they are promising to protect people and critical infrastructure.

 

[DayTripping]

Thanks so much for doing this. Get they "buy you a drink" button and I'll contribute.

 

[Lark]

Good Day Ladies and Gents, and especially the fellow nerd who will actually read this!

This is the moment you've all been waiting for (well, the 3 of you who were heavily invested in debating the efficacy of aftermarket cabin air filters in a vendor post on this very forum).

Report on Rivian OEM & Aftermarket Cabin Air Filtration Performance with respect to Penetration and Pressure Drop​

Introduction
This report aims to evaluate the performance of the Rivian OEM (Mann) air filter in comparison to available aftermarket HVAC / Cabin Air Filters. Given the industries we serve and the industry regulations around personal protective equipment (PPE) regulated personal air filtration, we do not have the ability to test exactly for automotive spec HEPA filtration.

The automotive standards for automotive filtration can be found here: https://www.aivc.org/sites/default/files/members_area/medias/pdf/Conf/1999/paper095.pdf
Notably, the ability to performatively test to 105 L/s (liters per second), 70 L/s, and 35 L/s are the defined flow rates for this industry and compliance governance. Our equipment can test up to 120 SLPM but is typically calibrated to test at 85 SLPM (standard liters per minute) and below. Therefore, our testing was performed initially at 85 SLPM and re-performed at 32 SLPM for comparative reasons, as is standard practice in all filter leak testing standards and regulations.

The equipment: I have access to ATI’s 100X Automated Filter Tester which is certified and compliant with NIOSH 42 CFR Part 84, ISO 23328, GB 2626, JICOSH/JMOL, GB 19083, GB/T 32610, YY0469, YY 0469, EN 12941/12942, EN 143/EN 149, ASTM F3502-21, ASTM F2100-23, and our company is in the process of certifying for ISO 17025 compliance.
The 100XS we used tests at the Count Median Diameter (CMD) of 0.075 μm ± 0.02, with a Geometric Standard Deviation (GSD) of ≤ 1.86, with typical concentrations between 15 and 25 mg/m3. Our challenge aerosol of choice was Salt (NaCl) solution with a flow accuracy to ± 0.4% of reading, plus ± 0.2% full scale. Aerosol detection specifications are as follows: Dynamic Range 0.1 μg/m³ to >200 mg/m³, accurate to ± 1% of reading; Penetration 0.0005%; Efficiency 99.9995%. Our unit and all the reagents, components, and supporting equipment comply to the most recent published and ratified standards and certifications as validated by third party lab testing for: CE, RoHS, FCC, and CSA.

Generally, this test equipment is provisioned for use with Flat sheet Filter media, Filtering Face pieces, Medical Device filters, and PAPR filters of all types and geometries including HEPA and ULPA grade and electret media. Typical industry use case of this equipment is to test and quality control validate filter media, cartridges, and industrial hygiene applications.

We used our standard automatic [filter media holder] chuck outfitted with a custom adapter that was designed to fit the geometric size of Rivian’s designated cabin filter cartridge location. To note: the orientation of measurement is relatively oriented orthogonal to the mounting of Rivian’s air collection, but would maintain the same fluid path, nonetheless. Also to note: the test fixture was developed to seal along the topmost boundary edges of the filters, which should mimic the intended sealing surfaces of Rivian’s air intake design.

Assumptions
The following assumptions were made:

• All filter media is nominally installed according to the vendor’s intended fluid path. (In other words, we did not ‘flip’ the filters to test reverse flow path or alter the path in any meaningful way.)
• All filter media should be fully sealed along the perimeter of the filter, as installed. Any opportunity for fluid flow around the filter, would essentially negate the intent of the filter by allowing for unfiltered air to enter the HVAC system.
• The OEM Rivian filter is considered the ‘standard’ and the remaining filters are compared to the OEM.
• As noted above, given the limitation of our equipment to challenge the performance of automotive cabin air filters, we are only utilizing this is as a comparative analysis of characteristics for penetration performance and pressure drop between the OEM and aftermarkets.

Disclaimers
I CANNOT and do not certify performance of these as HVAC air filters. I am credentialed and trained as a Mechanical Engineer to develop and integrate the test equipment (as noted above, for the intents and industries noted above) but am not a certified air filtration engineer or media certification technician by any stretch of the definition. I did work directly with a PhD Filtration Applications Engineer on this testing, and he is remaining anonymous as we’re not doing this as a professional endeavor.

All content is for educational purposes only. We do not intend for the content to be a substitute for professional advice or evaluation, counseling, certification, or formal representation outside of the scope of this comparative effort. Our content doesn’t engage visitors into a professional relationship.

Testimonials from myself and our engineers reflect our personal experiences and outcomes. Testimonials do not guarantee, warrant, or predict these or any other results. Every test setup is unique, and we did not procure a statistical sample of filters at regular QAE inspection point intervals.

Before posting any content, we do our best to ensure the accuracy and completeness of the information.

Raw Data
The following is based on the testing and test setup using an ATI 100XS configured Automated Filter Leak Tester and input and expertise of our Applications and Field Engineering team.

OEM Rivian Test Filter
Test 1:	85. SLPM
	Penetration (%)​	Resistance (Pressure Drop, mm H2O)​
	4.5​	0.2​
Test 2:	85. SLPM
	Penetration (%)​	Resistance (Pressure Drop, mm H2O)​
	8.7​	0.2​
NOTE: There are concerns will the sealing of this filter about its perimeter
Test A:	32 SPLM
	Penetration (%)​	Resistance (Pressure Drop, mm H2O)​
	2.2​	0.2​
NOTE: There are concerns will the sealing of this filter about its perimeter
Test A:	85. SLPM	DIRTY/used OEM Rivian Test Filter (16,117 miles)
	Penetration (%)​	Resistance (Pressure Drop, mm H2O)​
	49​	0.2​
NOTE: There are concerns will the sealing of this filter about its perimeter
Test B:	32 SLPM	DIRTY/used OEM Rivian Test Filter (16,117 miles)
	Penetration (%)​	Resistance (Pressure Drop, mm H2O)​
	21.25​	0.2​
NOTE: There are concerns will the sealing of this filter about its perimeter

Aftermarket Filter #1

Test 1:	85. SLPM
	Penetration (%)​	Resistance (Pressure Drop, mm H2O)​
	7.9​	0.7​
Compared to Target:​	176%​	350%​
NOTE: There are concerns will the sealing of this filter about its perimeter
Test 2:	85. SLPM
	Penetration (%)​	Resistance (Pressure Drop, mm H2O)​
	10.8​	0.8​
Compared to Target:​	240%​	400%​
Test A:	32 SPLM
	Penetration (%)​	Resistance (Pressure Drop, mm H2O)​
	13.35​	0.8​
Compared to Target:​	297%​	400%​

Aftermarket Filter #2

Test 1:	85. SLPM
	Penetration (%)​	Resistance (Pressure Drop, mm H2O)​
	1.96​	0.5​
Compared to Target:​	44%​	250%​
Test 2:	85. SLPM
	Penetration (%)​	Resistance (Pressure Drop, mm H2O)​
	1.7​	0.8​
Compared to Target:​	38%​	400%​
Test A:	32 SPLM
	Penetration (%)​	Resistance (Pressure Drop, mm H2O)​
	0.7​	0.8​
Compared to Target:​	16%​	400%​

Aftermarket Filter #3: Every Amp

	Test 1:	85. SLPM
		Penetration (%)​	Resistance (Pressure Drop, mm H2O)​
		0.15​	0.6​
	Compared to Target:​	3%​	300%​
	Test 2:	85. SLPM
		Penetration (%)​	Resistance (Pressure Drop, mm H2O)​
		0.18​	0.6​
	Compared to Target:​	4%​	300%​
	Test A:	32 SPLM
		Penetration (%)​	Resistance (Pressure Drop, mm H2O)​
		0.06​	0.6​
	Compared to Target:​	1%​	300%​

Analysis (Informal)
A few very important notables:

• Rivian OEM (Mann) air filter does not appear to have been engineered to seal on all 4 sides of its perimeter (you can see this based on the ‘fuzzy’ gasket manufactured into the edge of the filter housing). It’s also very concerning, and notable to our AE that the outer edge is not rigid. Best practice when developing filters is to have a hard boundary edge that can seal against a mating surface.
  This could be overcome with appropriate gasketing on the cartridge (or installation provision) of the air handling equipment. As far as we could tell, no such provision is made. We could be wrong, but in our opinion, Rivian’s OE filter, when installed properly, is likely to leak. And as can be ascertained from the data, likely leaks more over time.
  
  
• Note that, when compared to Rivian, all Aftermarket filters have a higher pressure drop. This means that the path of air flow has a higher resistance versus OEM nominal. THAT SAID, even though the numbers appear extreme (300% greater than OE), it’s likely that:
  A) this is incurred due to a better seal than OEM (air cannot leak by, therefore it all has to filter through the media, which is the desired convention) and
  B) Even at the uppermost value of 0.8 mm H2O, we do not feel as though that’s a significant enough pressure delta to incur any measurable mechanical impact on the air handling systems. Especially when accounting for the cross sectional area of the filter that the fluid may flow through. However, this should be monitored over time (in other words, how much does this increase over time.)
  - It should also be noted that the OE ‘used’ filter did not incur an increase in pressure drop, which further informs the leakage. There were no obvious surface defects in the pleated fibers, and based on what we were seeing, still believe that the filter was leaking around its perimeter, which seems to have weakened over time (with use).
  
  
• Based on the data, 2 of the 3 aftermarket filters are suitable for use, both performing significantly better over the OE filter from a penetration standpoint. As noted, our equipment is designed to challenge filtration media in the HEPA particulate range and has a nominal particle size distribution (PSD) that covers the range of challenge as an industry standard as such. Technically, to qualify as a “HEPA” filter, the design must reduce the HEPA particulate size penetration by 99.7%. So, a penetration value less than 0.3% would certify that metric.
  
  
• Based on #3, Rivian’s own OE filter is NOT likely HEPA compliant.
  The only filter that was hypothetically able to reach HEPA compliance (by our metrics, which again comes with the gigantic caveat that we’re not challenging this filter media to spec due to the difference in industry standards) was the final filter (Aftermarket #3) which achieved 0.15, 0.18, and 0.06% penetration (<0.3%) as tested.

Recommendations

• More cost is not better. The most expensive filter on this list, Aftermarket Filter #2, with shipping and taxes made it over $40. While it did outperform Rivian’s OE, it likely did so for the simple fact that it seals about the perimeter.
  
  
• All 3 of the aftermarket filters appeared very similar to one another from an aesthetic standpoint. In fact, in a blind test, I don’t know that I would be able to identify which is which. There is only subtlety when it comes to markings, and none of the filters had the vendors’ information listed (no branding, logos, trademarks, etc). The only notable text was with respect to install orientation. That said, don't judge a book by its cover: clearly the functional and internal mechanistic properties of these filters varied significantly, and there is a clear performance delta between all of them. [What matters is on the inside]
  
  
• The better performing filters fit compliantly (read: more snugly/ tightly installed) into the test fixture (and the Rivian Filter Cartridge/Tray).
  
  
• It’s possible that a ‘looser’ test fixture may result in a better OE performance filter, as it may have prevented some distortion on the outward edge of the Mann filter. It’s very difficult to tell, as I don’t have the exact geometry Rivian was using and didn’t tear the Cabin Filter Cartridge/Tray out of the truck to get more accurate geometry. The test fixture was developed by measuring all the filters themselves and determining a best-practice path forward to incorporating it into our test setup.

Conclusion
Given the costs, performance data, and observations, I personally will use Aftermarket Filter #3 heretofore. There may be OTHER manufacturers out there that I have not tested that could perform better (or worse, of course). But I single-handly financed this testing, so I stopped at 4x new Rivian Filters and the cost of the adapter and my time.

Appendix
All citations and references are included within the document.

Relevant images of test setup here:

Thanks for sharing!

 

[Phazor]

Thank you for doing this work and sharing it with us. New filter ordered

 

[norivian]

Off topic but related to filters: Just a few days after I picked up my Gen2 R1S, there is already a bad smell coming out of the vents. It’s an old filter sour-like kind of bad smell. Is it this filter or there is another filter?

 

[R1T Preds Fan]

Thoughts on K&N’s available reusable air filter? Any chance you plan to test this option. I’ve had great performance of these in my previous vehicles…

 

[R1Thor]

Thoughts on K&N’s available reusable air filter? Any chance you plan to test this option. I’ve had great performance of these in my previous vehicles…

I can test it, but to be clear: K&N doesn't advertise filtration efficiency. This is not advertised as a "HEPA" filter. So, really I would only be a comparison to Rivian's OEM (unless we're pleasantly surprised and it's super awesome and they simply don't 'certify' to HEPA)...

Any chance you'd mind splitting the bill? I know it's only $40, but I've fully funded this project to date. I think I'd mentioned it earlier in this thread. I'll test any/all filters people request--I already have the fixturing and obviously access to the equipment. It's just that: the filters aren't free

 

[ThirteenElectrics]

Again, thank you for informing us. I had two of the recommended filters (which I already owned) installed this morning. The gigantic HEPA filter is the best feature of the Model X and came in very handy during forest fires. I would love that level of air filtration in a Rivian.

 

[mudito]

I can test it, but to be clear: K&N doesn't advertise filtration efficiency. This is not advertised as a "HEPA" filter. So, really I would only be a comparison to Rivian's OEM (unless we're pleasantly surprised and it's super awesome and they simply don't 'certify' to HEPA)...

Any chance you'd mind splitting the bill? I know it's only $40, but I've fully funded this project to date. I think I'd mentioned it earlier in this thread. I'll test any/all filters people request--I already have the fixturing and obviously access to the equipment. It's just that: the filters aren't free

Get a donation button somewhere and publish it in this thread, I'd definitely share you a few bucks for a beer/coffee or filters

 

[shap]

First of all thank you for your great work on this!!! Definitely will look for a "beer" button!

I received the filter and installed it. Good tight installation, indeed seems to filter very well, MUCH better than OEM.

Said that the airflow is SIGNIFICANTLY lower. Most probable because the original OEM was really not sealed as you correctly mentioned.

 

[R1Thor]

I hid the link in my signature some time ago...

But for those who have been asking for it (and I want to emphasize, I'm happy to have done what I did unrecompensed , and I do appreciate the recognition and support)!

Buy me a coffee

 

[mudito]

I hid the link in my signature some time ago...

But for those who have been asking for it (and I want to emphasize, I'm happy to have done what I did unrecompensed , and I do appreciate the recognition and support)!

Buy me a coffee

;-)

Sponsored