Honda Motor Co. said Thursday it has developed a compact cogeneration device for households and will market it at roughly 200,000 yen by the end of March.

The device, which supplies both electricity and heat, will enable an ordinary household to save 40,000 yen in energy costs a year, the automaker said.

Running on natural gas supplied by regular utilities, the unit will be marketed in conjunction with Osaka Gas Co., Toho Gas Co. and Saibu Gas Co., it said.

Honda claims the device, which is 94 cm tall, 64 cm wide and 38 cm deep, incorporates the world's smallest natural gas engine.

The device is expected to last 10 years, and Honda recommends it be subject to maintenance checks every three years.

Starting July, Honda will test the device in 75 households in preparation for marketing, it said.