Every house hase on…yet there is no standard Lovelace card for water heater/boilers and the existing thermostat cards for climate do not support water_heater domain.
EASY FIX: Why can’t water_heaters be used in thermostat cards? The water_heater domain was broken out of the climate domain in HASS 0.81.
@tom_I Yes, there is an API and there are already Home Assistant integrations, but there is no consistency between them and they are generally implemented as generic sensors with services.
In fact, there is a whole category of integrations for Water Heater, just not consistency or derived entity base class with common services.
The existing thermostats in Home Assistant are “climate”, which doesn’t quite apply to these devices.
@tom_l my mistake, there is a water_heater domain that most integrations have switched to (they used to be climate). The issue is more having a card that supports water_heater domain entities.