While the knowledge was already out there that the HEPA filter used in the Tesla Model X, and now the Model S as well, is substantial and takes up a lot of space, words are one thing and sight is another.
A commentator on the Tesla Motors Club forum by the name of “pth28” was nice enough to recently post a picture of the filter though, addressing this blind spot in most people’s awareness of the feature
Accompanying the picture was the comment: “For those of you that want to see where the HEPA filter is located in our X.”
Certainly an effective-looking, substantial filter. Though the secondary portion of the filter, presumably featuring activated carbon or HEGA cloth to absorb gases and smells, isn’t visible as it’s no doubt further in the filtration chain (so as to not ruin its efficacy rapidly).
As noted in some of the followup comments, the size certainly explains why the frunk has taken a hit to its capacity since the air filter inclusion. I wonder how this will work with the Model 3, will the frunk be more or less eliminated with the air filter option?
Another followup question pondered why such a large air filter intake was needed. This was answered in an interesting (and somewhat funny) way by “ohmman” who noted: “My guess is that in order to pressurize the cabin, there’s a required flow rate of incoming air (to overcome outbound air). The filter’s flow capacity might require a certain amount of square inches to accommodate that flow. That number of square inches? One million, as you see in the OP’s photo.”
Those wondering about the filter’s efficacy may want to read what owner “Cosmacelf” had to say: “No wonder the air is much cleaner in my X! It is a very noticeable difference in the smells you smell in my S versus the X.”
On the subject of filter lifespan, the commentator “apacheguy” brought up an important, often overlooked fact: “HEPAs can last much longer than 2 years. As the loading increases the filter becomes less efficient at moving air through but more efficient at capturing smaller particles.”
That’s what drives the replacement of the HEPA filters themselves in air purifiers — the reduced air flow that results from long-term use (clogging), not a noted reduction in the capacity to filter. So, if you’re cheap, you don’t really “need” to replace them every few years — they may cycle less air than previously, but they do work.