From: Tony Williams 

Geo wrote:
> "Tony Williams"  wrote in message
> news:4399df01$1{at}w3.nls.net...
>
>
>
>>We need chamaeleon roofs: dark when the sun's shining, light when it
>>isn't. Maybe I could buy a few crates of photo-sensitive sunglasses and
>>use them as shingles.
>
>
> That's great if you live in buffalo and it's January but in a greenhouse
> world you probably want to reverse that to keep the heat down.

Yes you'd need two versions, one for a cold climate and one for hot. It
does answer your original question about why we have dark roofs though:
they were designed in cold climates.

--
Tony

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