There are plenty of energy efficient water heaters on the market these days. Not all of them can be controlled with your mobile device though. These smartphone compatible water heater controllers make it easier to keep an eye on your hot water availability and consumption:
Aquanta Digital Water Heater Timer: a WiFi smart water heater controller that shows hot water availability and weekly/monthly usage data. It integrates with IFTTT. Lets you put your water heater on a schedule.
DEWENWILS WiFi Outlet Box: you can use this for your water heater, pool pump, fountains, and mower. It comes with app and Alexa control. This outlet box is outdoor rated and has a waterproof pad.
HUUM UKU: an app controlled sauna heater control. It lets you delay start it up to 48 hours. It comes with a door sensor to retain heat. It shows set and current temperature.
PowerX: a smart water heater controller that learns how you prefer your water and automatically adjusts while reducing your power use and water consumption. It offers real-time monitoring and works with gas, oil, electric, tankless, and most other water heaters.
Have you found smarter water heater controllers? Please share them here.