No experience yet, but construction on one will be starting soon. A good book, if you can find a used copy, is The Solar Greenhouse Book by James McCullagh. Written in the 1970's it is still a useful introduction. Newer coverings are available now, such as polycarb plastics but all in all, it is loaded with worthwhile info.

The difference is all about orientation and insulation and efficiency.

I have converted an old dog shed into a greenhouse/shadehouse. I have put laserlite clear sheeting on the roof and half way up the sides. The top half of the sides are louvre windows that are easy to open and shut as need be.
In winter it is all closed up, and in summer its opened up and shade cloth pulled over the roof.
Works a treat. Here is a shot of it.
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Cheers Mantis

GREAT IDEA. IVE STARTED MINE AND I WILL USE SOME OF YOUR IDEAS. HOW DO YOU HEAT IN FREEZING WEATHER ? BILLTEX

Billtex - I dont heat it in winter. Our winters are mild compared with most in the US. I think we only had two frosts last winter. Even on an overcast day the greenhouse gets up around 20 deg C or 65-70 deg F.