In general the answer is approx. 30 cm below a ceiling or away from the corner of a wall etc. but please refer to your instruction manual for your heaters specific recommendations.
Surprisingly, the reason for these recommendations isn’t due to fire hazard as the heaters, although very hot to touch, are designed to be safe with a reflector directing heat forward. The main reason for making clearance recommendations is that any closer and the heat will discolour or damage the nearby surface over a period of time.
Please remember when choosing your mounting location that the heat will be directed forward and downwards in a cone shape and in order to feel the heat, you need to be within that cone. So in addition to a minimum distance around the heater, we would recommend a distance above ground of approx. 2.3m to 2.5m.
If you’re in any way unsure about the mounting for your specific location, please contact us with details for expert advice.