Hot Roof

[smatthew]

It was mid-day - the sun was overhead the whole time and the burn was on the crown of my head. SPF50 would not prevent me from burning with 2 hours of mid-day exposure, especially as pale as I was at that point. When I put my baseball cap on in the car it was quite uncomfortable because my scalp was already pink and painful.

Wait, let's do the math. SPF 50 means your two hours of sun exposure in the car are the equivalent of standing in the sun for 2 minutes and 24 seconds.

sun burn in 2 and a half minutes? Not to mention, symptoms of sun burn occur a couple of hours after the sun exposure. The time line just doesn't add up.

 

[AZAV8R]

Tint will not help. Darker the roof more sunlight its going to consume making glass even hotter. You can lower amount of sun radiation coming to your interior but roof will still be hot. The only possible way to solve this by insulating the roof,like every other car is made or by applying silver film on the outside of the roof glass.

That is not my experience. When I put 20% ceramic film on my roof, it was significantly cooler. Prior to that I had a sunshade there. The shade was cooler than tint, but I missed the view.

 

[AmokTime]

Wait, let's do the math. SPF 50 means your two hours of sun exposure in the car are the equivalent of standing in the sun for 2 minutes and 24 seconds.

sun burn in 2 and a half minutes? Not to mention, symptoms of sun burn occur a couple of hours after the sun exposure. The time line just doesn't add up.

Certainly makes sense if the UVB protection of the roof is less than “rated” UVA protection you’ve quoted. It also makes sense if the SPF value you’ve quoted is not accurate. Also, it has never been my experience that sunburn doesn’t show up for hours after exposure, just as the symptoms of thermal burns are not delayed. When I get burned, which can happen in as little as 15 minutes at mid latitudes, the red coloration and pain are nearly immediate. When I stay out too long in the sun, I go inside with the sunburn symptoms already present. They may grow more severe with time, but I am already in pain when I end my exposure, just as in this case.

 

[JBT66]

I’m having a hard time understanding this.
I just drove from Tucson to San Diego and back which took us about 6.5 hours each direction during the brightest parts of the day and roof is hot sure but no one got a burn or even tan except while we were at the beach for the week.

 

[SageBrush]

When I stay out too long in the sun, I go inside with the sunburn symptoms already present. They may grow more severe with time, but I am already in pain when I end my exposure, just as in this case.

@smatthew is right, your description does not fit typical sunburn. Either you are confused or you have something else. Perhaps solar urticaria ? You could try an anti-histamine as a diagnostic test and for symptom relief. Just be aware that the med does not prevent the problem so continue to limit your sun exposure.

 

[focher]

This is why I drive shirtless and lathered in coconut oil for that even brown tan. The white seats take a hit but it wipes right off!

 

[AmokTime]

Pretty sure it was sunburn. I’ve had it enough times to recognize it. It fits the pattern for people with very pale complexion. Just to be reasonable (and to put an end to this derailing of the thread), I’ll grant it is possible that my burn was a thermal one. The roof glass was far too hot to touch. The threshold of pain is usually about 120F. I’d estimate the roof was at least 140F, possibly hotter. This makes it emit IR inside the car, like when your oven is on “broil” (when the top heating element is on). My head is normally about 3 to 4 inches from the underside of the roof. UV + IR (emitted, not transmitted, so we don’t start another debate about the incredible IR-blocking power of the roof glass) could have resulted in a sun/thermal burn. Everyone satisfied?

 

[smatthew]

Pretty sure it was sunburn. I’ve had it enough times to recognize it. It fits the pattern for people with very pale complexion. Just to be reasonable (and to put an end to this derailing of the thread), I’ll grant it is possible that my burn was a thermal one. The roof glass was far too hot to touch. The threshold of pain is usually about 120F. I’d estimate the roof was at least 140F, possibly hotter. This makes it emit IR inside the car, like when your oven is on “broil” (when the top heating element is on). My head is normally about 3 to 4 inches from the underside of the roof. UV + IR (emitted, not transmitted, so we don’t start another debate about the incredible IR-blocking power of the roof glass) could have resulted in a sun/thermal burn. Everyone satisfied?

So next time just turn the AC down lower?

 

[AmokTime]

So next time just turn the AC down lower?

Now that I have an intuitive sense of the power consumption (about 6.4 miles per hour at 85F in direct, overhead sun with 76F setpoint) I can estimate the effect and be more liberal.

 

[Vines]

I bought the front and rear fully reflective sunshades for the roof. I put them up about 3 months of the year while the sun is especially bright. Significantly cooler interior temperatures result, especially on my face which is sun sensitive.

 

[jpfive]

I bought the front and rear fully reflective sunshades for the roof. I put them up about 3 months of the year while the sun is especially bright. Significantly cooler interior temperatures result, especially on my face which is sun sensitive.

Link to reflective roof shades please.

 

[Vines]

Sure, here you go.
https://www.amazon.com/gp/product/B07TCH4Y8W/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1