In article , Christian
McArdle writes
For instance, could I comfortably sit in the conservatory on a winters
evening without feeling chilly?

My calculations show that my conservatory should be eminently heatable in
winter. It has double glazed walls and ceiling. I haven't actually ordered
the heating yet, though.

Ours has polycarbonate roof & dg walls and is heated adequately by a 2KW
electric convector heater even on very cold days.
--
Tim Mitchell