The residential geothermal company Dandelion has raised another $4.5 million and added energy tech entrepreneur Daniel Yates as an executive board member and investor.

Big picture: New York-based Dandelion — which spun out of Alphabet's R&D arm last year — said the new round brings total funding to $6.5 million. Yates, the former CEO and co-founder of Opower that provides energy efficiency software to utilities, will bring experience in scaling an energy tech startup into something much larger.

One level deeper: The company is marketing geothermal heating and cooling to displace electric and fossil fuel-based systems, including propane and fuel oil common in the northeast.

• The company has around 70 contracts signed, and dozens of those systems have already been installed, a spokeswoman said.

Who the players are: Dandelion said the venture firm New Enterprise Associates led the funding round, while other new backers are Yates and the firms BoxGroup and Ground up. Existing backers Borealis Ventures, Collaborative Fund, and ZhenFund took part too.

More: Geothermal startup lands two solar vets for top roles.

Geothermal energy startup spins off of Alphabet's research arm.