The ‘Set to’ temperature in the tado˚ app

Toasty

New tado˚ user here, so please treat me gently.

I have a simple smart thermostat in my lounge. I have Geofencing and Auto Assist on. My Smart Schedule is set for heating to be on from 06:00 to 22:00 with a temperature of 20°C. My Away temperature is set to a minimum of 15°C. 

1. Yesterday, I was away overnight. Everything worked as expected in that tado˚ switched off the heating when I left. The tado˚ app showed ‘Set to 15°’ and the heating came on when the room temperature dipped below that figure the following morning. In addition, tado˚ switched the heating back on before my arrival back home. However, when I left again in the evening, the tado˚ app showed ‘Set to 18.2˚’. Where does it get 18.2˚ from and why? I never put that in.  

2. Although tado˚ switched the heating on before I returned due to geofencing, it was still nowhere near the target 20˚ when I arrived. I realise there is a preheat before arrival setting that ranges from Off to Comfort (I have it set to Balance), but does Balance get better over time as it learns how long it takes to warm up your system?

3. Regarding the Minimum Away Temperature, what is it best to choose in light of the average external temperature at a given time of year? I’ve read the FAQ article on the efficiency of allowing the internal temperature to cool due to the difference between internal and external temperature, but it doesn’t really offer any actionable guidance on choosing a suitable target temperature.

Thanks in advance for any help you can provide.

Toasty

Thanks very much GrilledCheese, that makes sense.