European Nest competitor Tado has raised $17.1 million to help grow its home climate-control business and “accelerate product innovations” and global expansion.

Some notable names participated in the round, including Siemens’ venture capital unit and Statkraft Ventures, the investment arm of one of Europe’s biggest renewable energy companies. This effectively doubles Tado’s total funding to date, as it raised $13.5 million last year and a $2.6 million seed round before that.

Founded out of Munich, Germany in 2011, Tado currently offers two products across Europe, the U.S., and Singapore — a smart thermostat and smart air conditioning control, both of which can be used with most existing heating and A/C systems, connecting them to the Internet so they can be monitored and managed via smartphone apps.

As with other similar systems, the Tado setup can establish whether anybody is home or not, and automatically alter the heating or A/C accordingly. It also taps weather forecasts to adjust the temperature in the home, and promises to save users an average of 31 percent in energy costs.

It’s estimated that the so-called Internet of Things industry will see almost two billion devices become “connected” to the Internet by 2020, including home cameras and even refrigerators. Companies such as Google-owned Nest and Tado are leading the way, with the European smart thermostat market alone estimated to have earned revenues of $152.5 million in 2014, a figure that’s expected to rise to $2.5 billion by 2019.