Wouldn't it be great if your bathroom knew when you were entering the room and adjusted the bathwater temperature accordingly? Panasonic's HE-KU37CQS water heater gets close to doing just that.
The sensor-equipped heater, scheduled to be released in Japan on July 10, stops the bathwater temperature from remaining constant when no one is in the bathroom. When the heater's wall-mounted sensor detects motion, it reheats bathwater in two minutes' time. As a result, the device can cut power consumption by up to 35% in the winter--when energy use is typically at its highest.
In comparison, standard water heaters measure bathwater temperature constantly and reheat water every 15 minutes regardless of the rate of heat decrease.
Panasonic's snazzy technology doesn't come cheap. The 370 liter device will be priced at ¥819,000 ($8,211), and its remote control is sold separately. It could be worth it, though, if you treasure both bath time and the environment.