While I've never seen it in person, there are a lot of examples online of the glass roof on the Tesla Model 3 and Tesla Model X sometimes have a very strong orange tint. Some owners love it, some hate it, apparently it's totally normal, but here's what causes it.
There is no denying the 2018 Tesla Model 3's importance. It is intended to be Tesla's volume-seller, the car that will hopefully make luxury electric cars more accessible to more people, especially when the long-promised $US35,000 ($49,123) version hits the market. It is the key to Tesla's future, the source of many of its struggles this year, and an EV — hell, a car, period — truly unlike any other.
You can see a good example of the orange-looking glass, which is commonly referred to as rainbow glass, in this video from Model 3 owner Bjørn Nyland:
All three of the cars Tesla currently sells are available with a glass roof option, and since that opens the interior of the car to more sun exposure, you can't just throw regular old glass up there. You need special glass.
The orange-red colour comes from a layer within the glass panels of the Model 3 — you can also see it on the Model X here — which is designed to reflect certain wavelengths of light, including UV and others, and reflect the sun's heat away from the interior.
This is particularly important for an electric car like the Model 3 because if the interior is hotter due to the glass roof, you're more likely to run the air conditioning longer, and that's just more drain on the battery and less electric range for driving. According to a European glass trade association, this type of layered glass, designed to reduce cabin heat, can improve a vehicle's overall efficiency by 2 to 4 per cent.
The orange colour of Tesla's glass indicates it's not likely to be a metallic layering, which is also occasionally used to reflect heat in automotive glass, but is usually tinted silver or gold. The problem with metallic glass layers is they can interfere with mobile phone, GPS and infotainment system signals, which is obviously not ideal for a modern car.
(That's why you'll sometimes see an F-22 fighter jet's canopy looks like gold, too, as it works along the same lines with stealthily hiding from radar.)
In almost every example where the orange layer of the glass is visible, the car is also wet. It seems to be most visible either early in the morning with dew, after some rain, or as Road & Track caught in some of its photos from its Model 3 review, after a car wash. It seems that the water sitting on the glass causes the light to refract in such a way that makes the inner layer more visible.
The orange colouring doesn't cover the entirety of the glass on the car though, not appearing on most of the windshield and most of the rear window on the latest cars.
It's unclear why, since the layered glass is designed in a way to not be too heavily tinted from inside the car, but owners on Tesla forums have speculated it could be to avoid the strange visual warping looking through the windows on earlier Tesla cars.
While I'm certainly glad the orange look only seems to show up in specific conditions, I think it looks cool! It looks futuristic and also sort of retro-wavy. It's rad. If you don't like it, too bad! Burn in the sun! Or get over it!