Hi Yves,
I just joined the forum because in real terms I just became a gardener. However, in my old house, and small garden, I did grow a few exotics. Palms, cycads, carnivores, etc. I've retired, moved, and at last I can put up a proper
greenhouse. I was going to put it in the back garden which is north facing and took professional advice. That advice was that if I want to grow loads of exotics then northern aspect is not advisable (in fact it's a no-no). It's not just a case of temperature but mainly of that good old God given thing - sunlight.
We went back to the planners and my
greenhouse is now moving to the side of the house, westerly facing but with full sun from about noon. (It appears that afternoon sun is better than morning sun for
plants). West is apparently OK.
Hope this is of help to you.