Filter Air Flow Direction

[nate704]

I opened up the HEPA filter housing and I am confused. The way it came from the factory is that the two prefilters which are placed on top of the HEPA filters have arrow marking pointing up toward the hood.
Isn't the air flow supposed to go down toward the bottom of the car?
TESLA instruction page shows a video and step by step instruction, but they tell the opposite directions. The video shows the arrows pointing down, but the step by step instruction below says arrow up.
Can anyone help me out here?

Model Y Do It Yourself | Tesla

service.tesla.com

 

[Goobers]

Practically speaking, it probably doesn’t matter.

For most filters, the air is still going through the same material (and amount of it). Just don’t flip them around after using them a while, unless you want it to dump all the particulates it caught up till then, into your cabin/lungs.

Some filter material is too soft/flexible for the airflow, so they have bracing to hold it in place, otherwise it’ll get pulled/pushed through or deformed enough to be useless. Bracing both sides isn’t worth it, so they design and brace for one direction of flow.

Probably more important is to remember filter type order. Not everyone would know that one is a prefilter (probably should, but there are all kinds of folks out there).