Approximately a year ago, a local start-up company offering geothermal heating and cooling systems for homes and offices was facing rapid expansion: they had 12 systems in the ground and five in the works.Twelve months later, according to its owners, Sierra Eco Systems has completed 13 systems this year, has 19 open jobs, and 16 qualified prospects. The company has also become one of the top five Hydron Module dealers in the entire country.Partners Ric Rowlatt and Bruce Sanguinetti attribute this growth to customer referrals, increased marketing and more education on renewable energy."We are seeing a more educated customer," said …