I have a warm water boiler / water heater where I live now. Running fully on electricity, which I have 'made smart' with Home Assistant. First of all I replaced the analog temperature sensor with a digital DS18B20 connected to a Raspberry Pi. I 'calibrated' this sensor with another sensor at our main faucet in the kitchen, so I can set the tap water temperature. Secondly I've added a power monitoring smart socket to the water heater, so I can switch it remotely. Finally I've added both to Home Assistant as a climate device, so I can easily control it.
Simply put I've set it up that during electricity peak times the boiler doesn't try to heat water to save on electricity costs. Heating water is all done in the off peak hours with some easy calculations. Also I tend to set my boiler to a lower temperature (ie. 58 degrees) during weekdays and higher (60+) during weekends or holidays. That way I always have hot water and get rid of legionella growth.
What I can see I'm using about 1.5 - 2kWh a day for keep 100 liters of water at at least 55 degrees. While the manufacturer of the water heater says the device should use between 7 and 9kWh a day. I really would like to optimize it any further, but it seems that I've hit a wall.
Simply put I've set it up that during electricity peak times the boiler doesn't try to heat water to save on electricity costs. Heating water is all done in the off peak hours with some easy calculations. Also I tend to set my boiler to a lower temperature (ie. 58 degrees) during weekdays and higher (60+) during weekends or holidays. That way I always have hot water and get rid of legionella growth.
What I can see I'm using about 1.5 - 2kWh a day for keep 100 liters of water at at least 55 degrees. While the manufacturer of the water heater says the device should use between 7 and 9kWh a day. I really would like to optimize it any further, but it seems that I've hit a wall.