A Nest thermostat in action. Image source: Nest.

Google (GOOGL -1.97%) just announced a $3.2 billion cash agreement to buy privately held Nest Labs. Nest is best known as designer of the Nest Learning Thermostat and generally aims to "reinvent unloved but important devices in the home" such as thermostats and smoke alarms.

In a corporate blog post, Nest CEO and co-founder Anthony Fadell noted that Nest has been working closely with Google almost since the company was started in 2010. Google's investment arm has participated in several rounds of Net's venture investor funding, including the $150 million round that valued Nest at $2 billion two weeks ago.

Nest is growing quickly on its own, Fadell said, but putting Google's resources behind the company will accelerate the growth curve. "Google is committed to helping Nest make a difference, and together, we can help save more energy and keep people safe in their homes," he said.

Google plans to operate Nest as a separate company, keeping the Nest brand intact. Nest co-founder and engineering chief Matt Rogers said that the company's products will continue to support both Android and iOS apps, and that users should see almost no change to their Nest experience under Google's control.

After going through the usual regulatory approvals and other closing conditions, the deal is expected to close "in the next few months."