The terrace heaters are turned on from inside the house.Â
The two above the large outdoor table are turned on on the switches above the plant by the sofa
The one above the lounge chairs is turned on on the switch on the inside wall near to the outside wall-mounted ash tray.
There is no clear indication when looking at the switch whether the terrace heater is on or off, so make sure to turn it off once you finish, because the terrace heaters each draw 2000W, so it can get expensive to forget.