The "smart thermostat" makers known as Nest, is now hot on a lot of people's radars. It has just gotten a $2 billion valuation.

The figure is based on a $150 million round of funding led by DST Global, according to a report in Re/code. The report states that the valuation could be as high as $3 billion.

Their last valuation figure was $800 million, based on an $80 million funding round last January.

Founded by former Apple employees Matt Rogers and Tony Fadell, it has got more than 200 employees now. They have not disclosed their revenues yet, but it was reported to have shipped 40,000 thermostats a month. Each retail for $249.

Nest introduced its $149 Nest Protect smoke detector in October. The device promises fewer false alarms.