Google says it is buying smart thermostat start-up Nest in a deal valued at $US3.2 billion ($A3.57 billion).
"They're already delivering amazing products you can buy right now -- thermostats that save energy and smoke/CO alarms that can help keep your family safe," Google chief executive Larry Page said in a press release on Monday.
"We are excited to bring great experiences to more homes in more countries and fulfill their dreams."
The big-ticket buy continues a move by the California-based internet titan into consumer electronics hardware, adding smartphone-synched thermostats to its Motorola Mobility smartphones; Nexus mobile devices, and the promise of releasing Google Glass eyewear some time this year.
"Google has the business resources, global scale and platform reach to accelerate Nest growth across hardware, software and services for the home globally," Nest co-founder and chief executive Tony Fadell.
"And our company visions are well aligned - we both believe in letting technology do the hard work behind the scenes so people can get on with the things that matter in life."
