Hot water tank smart thermostat

I think there is a market to provide a variation on the Smart Thermostat in the form of a unit with a temperature sensor on a cable, to allow the user to install in a thermal water store.

This can give the flexibility for hybrid systems that have multiple heat sources for the store such as Solar thermal, biomass and oil or gas.

It could provide the logic and prioritisation, maybe two channels, one for top of tank and one for bottom to monitor thermal layering.

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  • Having done some more research on the Tado Smart Thermostat, I have found that the semiconductor IC used on the PCB is a surface mount Sensirion SHT20 Humidity and Temperature sensor. This sensor is an advanced device which has a high accuracy and level of integrated features including the I2C bus for communication, I2C bus is widely used in electronics and I believe was pioneered by Phillips for use in consumer electronics TV's etc. Having said this the possibility of creating a remote temperature sensor with 1-5 metre cable for remote installation using the SHT20 on a small PCB is straight forward possibility as the device only measures 3mm x 3mm x1.1mm and could be housed in a metal tube like PT1000 sensors or similar. a suitable connection at the thermostat like a RJ11 plug and socket would be an easy modification.

    I would be interested in everyone's comments on this as an option. Having see the comment from Tado saying the market is not big enough to justify does not cut it as companies like Sonoff seem to be capitalising from the increasing demand for this sort of feature?

    Best regards


    So, you'd likely have to emulate the sensor, and use some other bus protocol for that distance. Might as well use another sensor then, that already comes in the right form factor. And then it is only a small step to just completely roll your own thermostat. Too bad tado isn't an open system...