Fram offers two types: CF and CV. CF has charcoal and baking soda added for odor control, CV seems to be a HEPA filter and thus should filter better. Which one should I get? Wildfire smoke is my present concern. Thinking CV would be better, but would there be more restriction to air flow? Drove back from Lake Tahoe in my Gen 3 through smoke from the Caldor fire, and could smell smoke in the cabin with a 30K mile CF filter, but I think the charcoal/baking soda was pretty used up anyway.
i like the charcoal for diesel and other smoke/odors. not sure if hepa does that, but it is a very good filter for fine particles. restriction isn't an issue, but in both cases, i wonder if enough air leaks around the filter to make them less effective to certain contaminants
Cabin filters are not exactly gas masks. For example, if you happened to drive through a cloud of tear gas, I’m thinking it’d pass through. Not sure though…, sounds like a Myth Busters episode in the making…
The CV uses N95 filter material similar to medical masks. While they do improve filtration, the best solution is your recirc mode to avoid as much outside air as possible. There are two issues, one is recirc mode still allows a portion of outside air, just not as much as you get with recirc off. The second is your hv battery fan is forcing cabin air through the battery and sends it outside. So for every cubic foot of air forced out, replacement air comes in one way or the other. So restricting the cabin filter with a N95 may force more unfiltered air into the cabin through negative pressure caused by the battery fan.
Doesn’t all air flow go through the filter, so it doesn't really matter of the system pulls outside or recirculated air (minus leakage around the filter)? I wore an N95 mask when out hiking when it was smokey around here, and couldn't smell the smoke, so in theory, it should work.
We use charcoal activated in all of ours and since the lifespan is only a year they all get changed yearly, one of my summer duties.
I like the white ones cause I can see when they are dirty. N95 is supposed to protect lungs from wildfire smoke, might want to figure out howto add a few to the filter But the same concerns apply to the HVAC system as apply to humans wearing a mask. ie: in make it harder to breath. https://www.epa.gov/sites/default/files/2018-11/documents/respiratory_protection-no-niosh-5081.pdf It's a way out there idea and I'm not expecting anyone to actually consider it unless it give someone else a bright idea or two.
My point is the Fram CV cabin filters rated as N95 are more restrictive than factory filters. This will force the battery fan to pull in more unfiltered air from around the windows and other cracks. It may even reduce the battery air flow. Use of recirc mode and a charcoal filter would be my choice. Another factor is variable speed motors have been known to fail when too restricted. Their operating characteristics draw more current as they attempt to maintain rpm. Like most things Toyota, the best results are often gained with factory designs. The charcoal filter was factory. Obviously if you are sure its heavy smoke in your area, health comes first but I might then consider the Fram N95 on recirc. The motor is then primarily circulating inside air.
Now that I've read all the posts in this thread - It would be great if the CV is a Hepa. besides not reading everyones posts before I commented, sorry bout that.... My idea was actually getting N95 masks and customizing the filter somehow with a couple of masks attached. My concern about the HVAC system was the same as @rjparker s post above. But it would have to be a well thought out filter customization to keep the HVAC system happily working as normal. Also there are warning about counterfeit N95's I'm sure most are already aware of. but it's also something to keep in mind. Counterfeit Respirators / Misrepresentation of NIOSH-Approval | NPPTL | NIOSH | CDC counterfeit N95 search is even showing links to 3M's N95's (I'm not sure what that's about yet). Finally, I haven't seen anyone yet wearing a dual filter full face mask respirator, like are used in autobody paint booths, but if/as things get worse it just might happen, if it hasn't already.
My condolences for your poor lungs! ;-) My daughter bought a 2012 Sienna van last year and while helping her get it caught up with maintenance, I took out her cabin air filter..NASTY....it was, obviously, installed in the factory!!!
The funny thing about mechanical filters is that the dirtier they get, the better they work. The reason for replacing them is because they get "too good" and block airflow, which reduces the amount of clean air they can deliver in a given period of time. In terms of removing particulates they only get better as they get dirty. That's why we add diatomaceous earth to pool filters - we're pre-dirtying up the filter to make it work better.
in the case of the cabin filters " and charging twice as much for the pre - dirtied ones." I like adding my own dirt instead.
Sort of. Certainly the DE filter media and accumulated dirt is easily removable and the DE replaceable by simply reversing the flow. It is not recommended with cabin filters to preload them with anything. In larger AC and refrigeration applications excessive filter restriction can slow air flow enough to freeze coils. It can also cause x13 and ECM variable speed motors to fail. Luckily Toyota builds their blower controls pretty stout.
@rjparker Thanks for the advice and above all "point well taken". I will have to do a better job of indicating humor in my posts. " I don't really like putting dirt or anything else (well maybe a couple drops of essential oil) on my cabin filters.
I wasn't sure if the cabin filters I buy are HEPA so checked...yep, it says "REMOVES AND FILTERS 99.5% of all dust, pollen, air pollution, allergens, pet dander, and other airborne contaminants from the outside air before it reaches the vehicle's interior. "
True HEPA requires removal of 99.97% of all particles 0.3 micron and larger. That product you are quoting is using deceptive language to make it sound similar, but it's not saying the same thing. Dust, pollen, air pollution, allergens, pet dander, and other airborne contaminants can be larger than 0.3 microns. Since they can be larger, the manufacturer can get away with claiming their product is capable of the performance they claim. Ask them for their performance on particles of 0.3 microns. That's all a very long way of saying if it was HEPA it would say HEPA, like the Bosch 6055C for example. The 6055C fits the Prius Prime if you cut a piece of the filter holder that appears to serve no purpose other than to prevent you from purchasing third-party filters.
