Hot Tub Heating
I'm currently researching how I can heat my hot tub using my central heating. This will save a huge amount of money on heating costs, both because gas is cheaper than electricity and because it can be heated by roughly 8 degrees an hour using the boiler, rather than 1 degree per hour using electricity, it can be left at a lower temperature when not in use.
I'm planning on using a heat exchanger (https://ej-bowman.com/industries/hot-tubs-spas/) to do this so I've not got any hot tub water flowing through the boiler. The heat exchanger will sit in the system exactly like a radiator does. I'd like to use my tado system to control the setup. I can call for heat using the api to adjust the set temperature of my (currently redundant, as I have radiator thermostats in each room) room thermostat. I'm considering using an arduino to sense the hot tub temperature and operate a solenoid valve/call for heat when required.
While this should work well, what would be ideal would be to feed the hot tub temperature directly into tado and also make use of the scheduling already built into the system. That way tado takes care of everything (providing the solenoid valve is open when required) and makes for a much neater solution.
I'd like to know if anybody else has thought of something similar or has any suggestions. Perhaps having a virtual device that could be controlled via the app/api would be a great feature.