Do I have to place my thermostat at the suggested 1.5m height?

No – but try to place it around this height for optimum performance, or consider using an F type thermostat - this will control the system through monitoring the floor temperature only, making the siting of the thermostat less critical.

If using an AF type thermostat, try not to site the thermostat too close to the floor as this could cause the thermostat to switch the system off prematurely. You may need to make allowances for this when programming the temperature setpoints.