Hi Jamie
I make 2 different Versions the R-4 and the R-8 Pending your Camping sickness.
I also have recently made the prototype Outside thermals unlike the
inside thermals window covers that seem to just let a flow of cold
air from the bottom of the glass straight in. Mine will go on the
outside and you will heat up the inside glass the Radiant window
thermal will bounce the warm back at the glass instead of it being on
the inside it will bounce the cold back to the glass but it is
already inside. Should keep the Bus /Vanagon much warmer.

But most of your heat will be lost though the flimsy canvas up top if
you do not do some thing.
Hope this helps.
Check out the website both are listed there.
http://fanchers.com/59/VW%20Stuff.htm

If any questions feel free to let me know!
Jonce

>I am considering purchasing insulation for my poptop in my '89.  Can
>anyone give me suggestions to what they have done? Thanks.
>
>-Jamie Auch
>
>Sent from my iPhone