Hello!
I’ve got a narrowboat I’m deploying Home Assistant into, so far I’m wrestling with some ESP based lighting control for RGBW LED tape, and that seems to be going well, I have another big automation that I simply don’t know where to begin with so I’m hoping the community has some pearls of wisdom.
I want to use ESPs (code complied with the help of ESPHome) to monitor the temperature of a hot water tank and individual rooms on my narrowboat, and then open or close radiator valves with something like this ( https://www.underfloorshop.co.uk/product/emmeti-control-t-electrothermic-head/?attribute_options=230V&gclid=EAIaIQobChMI8uzf-JCr5wIViaztCh2bYAIqEAYYBSABEgJqS_D_BwE ) and if a room or the hot water tank falls below a set-point, and if any heating zones are below the set-point, send a demand signal (a relay showing 12V to the boiler) until the temperature of the appropriate zone rises above the setpoint, standard zonal heating control.
I used to install BMS systems in big posh houses, so I know the logic I need to run, just a little unsure where to start, does the automation creator have the fidelity to create this? or should I go with a .yaml file from the off, has anyone read a good blog post on the subject? has anyone deployed zonal heating control in this fashion using Home Assistant? if so, how was it? 
I understand I’m being a little lazy coming straight to the forum, I’m sure the info is out there, but some guidance would be greatly appreciated 