Small Greenhouse - Help!

Hi there,

I have decided to buy a small greenhouse for my patio. I haven't got the largest space, and it will be taking up the prime sitting spot, but I think it will be worth it!

Doing my research it seems that I am best buying a metal rather then wooden frame, with glass? Is this the easiest to maintain?

I may be looking to move in three years or so, would metal be easier to take apart?

I have a small space. How small a greenhouse can I go whilst still keeping a decent temperature. I will not be heating, but would like to use it over-winter some plants and to start seedlings sooner in the season. 

Anything else I should consider, or any recommendations?

Thanks all,

Natalie