Conservatorys depend on position too. On our old house ours got the sun in the evening, so unless it was a baking hot day it never really got too hot. If it was we just opened the doors onto the patio. It was a well used room, both summer and winter. We didn’t have underfloor heating, just an oil fired heater which warmed the room up.
Spent many a happy our in the recliner sipping Pimms 😉