I know that electrical heater with pilot wire / driver is a very french way to heat up the house but I currently have this installation at home and I want to find a solution for controlling all my heaters with a pure on-prem solution managed via HA.
For the hardware part I have found this local controller called ETH-PANEL: http://www.wifipower.fr/fr/eth-panel/66-eth-panel-fp4.html. If you already have an installation with pilot wires centralized into your power distribution unit this DIN compatible module seems to be a great solution.
This module also exists with WiFi WP-PANEL2: http://www.wifipower.fr/en/wp-panel2/55-wp-panel2-fp4.html if you don’t have the possibility to connect it to your LAN via Ethernet from your power distribution unit.
Unfortunately I have not tried it but as far as I know you can send orders with HTTP requests so I assume that this thing could be easily integrated into HA.
If someone has already tested it and integrated it into HA, I’m really interested by a feedback.