Bill N wrote:

> This was a very good discussion of why vehicles get hot.  I do have to point out that light
> does not "slow down."  It loses energy, but the speed of light is a constant in any given
> medium.  When it loses energy, UV becomes visible light, and visible light becomes infrared.
>

Yep, absolutely true.  I misspoke.  Thanks, Bill.

>
> Also, while it is true that after several hours in the sun a tinted vehicle will be the same
> temp inside as an untinted one (because the heat lost by conductance back to the outside is
> balancing the heat gain from the sun), it is also true that the tinted vehicle will take longer
> to reach this balance.  In other words, the inside will get hot more slowly.
>
> Bill in the Southwest

Also true.  This was the reason I was saying that experiment would be meaningless.  After a given
period of time, both the tinted and untinted vans will reach that point of equilibrium and thus,
the same inside temp.  The key is that reducing the amount of energy input reduces the net energy
gain.  Thus, an air conditioner that isn't capable of major cooling would stand a better chance of
being able to cool ones van.

I love this stuff,
Marc Perdue