How does the Hilo smart controller for electric water heaters work?

Hilo’s smart controller is like a switch: it turns the water heater on or off.

During a peak demand event, the controller will automatically turn off the water heater. The large volume of water inside will remain hot for several hours, so you can continue to use hot water during the peak demand event, though in moderate amounts. This helps maintain comfort in your home. Once the peak demand event ends, the water heater restarts and resumes normal operation.

During these events, the temperature probe located in the upper part of the tank and connected to the controller will automatically restart the water heater when the water  temperature dips below the threshold of 49°C.

Outside peak demand events, if the probe detects lukewarm water due to significant hot water use (i.e., if the water temperature dips below the 49°C threshold), you will receive a notification in the Hilo app. The alert will disappear when the new water in the tank is hot enough.

If the system doesn’t function as described above, it is important to have it checked. We also recommend reading the troubleshooting guide: The water in my water heater is lukewarm or cold. What should I check?

Outside peak demand events, the controller will not automatically restart the water heater if you’ve turned it off manually, even if the restart temperature is reached.

We don’t recommend turning off your water heater for short periods. This could leave you without hot water and won’t necessarily lead to additional savings. For more information, read the answers to the questions What are the risks if I run out of hot water? and Can I save more by turning my water heater off at night?