Person detected at home while no one was at home

[thegios]

Left home Friday at 06.41

Today Sunday I am still miles away but on Saturday someone at home was detected and heating turned on.

How could that be?

[Ashepherdson]

Hard to say for sure... It could be presence detection on your thermostat (sometimes motion can be light changing quickly .. ie a car light or shadow change) , one of your devices could have rebooted and woken up.. etc.