Residential geothermal startup Dandelion just closed a venture round worth $4.5 million, more than doubling its funding to a total of $6.5 million. Daniel Yates, co-founder of Opower, contributed to the round and will join Dandelion as executive board member. In addition to Yates, BoxGroup, Ground Up Ventures and previous investors Borealis Ventures, Collaborative Fund and ZhenFund contributed. New Enterprise Associates led the round. Dandelion is pioneering a new drilling technique to lower the cost of ground-source geothermal for homes. It's also using software for customer acquisition and offering financing packages, similar to the residential rooftop solar industry.