Daiwa House Industry Co Ltd is about to sell houses equipped with Li-ion rechargeable batteries and PV cell modules in about the spring of 2011 in Japan.

By using PV cells to store electric power in rechargeable batteries during daylight hours, it is possible to drastically reduce the amount of CO2 emissions and light and fuel expenses. The company plans to utilize the HEMS (home energy management system) to controls the power consumptions of home electric appliances and LED lighting equipment.

Kyocera Corp. provided LEDs to equip all of the lighting equipment in the house. And the LED lighting equipment is switched on and off by opening and closing the relay via the home server.
 
The LED lighting equipment is arranged so that it indirectly lights the rooms with soft light. By alternately arraying warm white LEDs and white LEDs and controlling the voltages of the two types of LEDs respectively, the LED lighting equipment emits sunlight color light during daytime hours and silica lamp color light during nighttime hours.