Glasses in both Model Y and 3 are UV protected.
This is true, but confusing.
Basically all glass and plastics are "UV protected". Most transparent materials block some UV A. Most laminated materials block a fair amount of UV-B. This is actually a big issue for thing like keeping reptiles that need UVA and UVB to develop bones.
Glass in commercial buildings and vehicles can block a percentage of UV radiation, however the amount depends on the type of glass. With vehicles there are a number of factors that influence the UV levels inside a vehicle such as whether windows are open or not, and the position of the vehicle...
www.myuv.com.au
In terms of tesla's, your front windshield is laminated, your side windows are generally laminated these days on new teslas (for noise, not specifically for UV). Your rear class is more likely just tempered safety glass, as is the roof. While this still blocks some UVA, it will let in most UVA, nearly all UVB. IR is also basically not obstructed.
Tinting your roof and particularly your rear window will have a significant affect, not only are these two windows mostly sun facing, they also generally are the most transparent to UV and IR. For your windscreen, it is illegal to Tint in Australia (AFAIK), but it is already absorbing most UV light. A reflective/light colour windscreen cover is probably best and can easily be removed before driving and placed before parking for long periods in the sun. After all even regular light can heat up your interior of the car, and tinting a front windscreen to be dark enough to significantly cut that light makes it dangerous to drive, particularly at night.
So tinting your rear window will probably improve things ~50+ % on its own, the roof, which has a coating, can be improved as can the side windows. While a coating may reduce light energy by ~50%, its still letting in 50%. An after market tint may reduce that to 25%.
Everyone I have spoken too seems to believe and feel and rate that tinting makes their tesla much more enjoyable in Australia with our powerful climate and solar intensity.
