Patti, eventually the inside of your van will be at ambient temperature (that 110 F you mentioned) if in the shade.  In the sun, it can get 40, 50, or more F hotter after a time, because of the glass.  Covering the glass is the most effective way to prevent that greenhouse effect.  That said, yes, the color of a vehicle can make a slight difference in the temperature rise due to sun. 

 A personal anecdote that is sort of odd:  I used to judge high school science fair projects.  A clever young woman had prevailed upon large auto dealers to allow her to place recording thermometers in the cars for sale, parked in the sun on their lots.  She analyzed the data using a multivariate statistical program, controlling for such details as car maker, body style, amount of glass, internal volume and a few others that I cannot recall.  Both external and internal color of the vehicle did make a difference, about 1.5 C, in cars that heated to over 70 C in the sun.  I believe that her experimental design was well thought out and valid, as were her data and analysis.

mcneely
-+
---- PB <pbrattan@GMAIL.COM> wrote: 
> The "paint guy," where I took my Westy for an estimate, seemed to think
> that a white poptop would not make a difference during hot weather.  Where
> I live it can go up to 110 degrees or more, but there are usually only
> about 20 or less of these days per year, and usually spread out in August
> and September. If it's 108 degrees outside, I can't see how a white rooftop
> could reduce the inside temp by more than 2 or 3 degrees, which would still
> result in a sizzling 105 degrees.
> 
> I'm wondering if there's any feasible or "creative" way to install
> Reflectix or any other type of insulation *inside* the poptop, or would
> there happen to be some kind of "paint on" insulation for the exterior...
> 
> Patti
> 90 Westy Automatic
> North Hollywood, CA
> 
> *♪♫**♥**♫♪♪♫**♥**♫♪♪♫**♥**♫♪♪♫**♥**♫♪*
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--
David McNeely