Humidifier

I don't know - I am anticipating simply a hole - but it may be sealed. The fixing kit produces a seal, but not a perfect seal.

It doesn't really matter. The air gap by itself produces nearly all the insulation effect. For instance secondary double glazing works perfectly well without a perfect seal. And a bit of condensation won't worry me too much. In the winter the whole sun room tends to have a lot of condensation.

My main concern is that I hope it will be able to control the temperature.

 

Of course another way to keep the temperature down would be exterior blinds... but that's another level of expense altogether!

 

Or to open a window - but they imply that someone must be there to do it. I got all my bits today for the extractor fan - just need the glass now. The extractor is in shining white which is out of keeping with my sun room where everything is in brown mock wood. I spent an age looking for a brown extractor, then had a brainwave - just spray it with brown paint - it apparently sticks well to plastic.