A9 Green / Total Green Energy Solution, LLC

A9 Green describes itself as an energy efficiency consulting firm based in Lexington, and in a 2023 Google review one customer wrote that they followed its recommendation, implemented insulation upgrades and had it complete its AeroBarrier system. For that 4500 sqft space, the 2023 reviewer said yearly energy usage had gone down to $3000. The company's site lists HERS ratings, AeroBarrier air sealing, Passive House and LEED certification support, and related building-science testing for homebuilders, architects and developers. It names Bijan Khosraviani, PhD, as principal and founder. A 2025 Google reviewer wrote that A9 Green did the blower door testing and that they were very pleased with the work, knowledge and professionalism. A 2023 reviewer said A9 Green was the HERS rater for their Mass Save renovation project, and that they got the maximum rebate and the maximum HEAT Loan. In a 2023 review, a customer said the company communicated well throughout the project and that it went smooth with the Needham building department. Sterling Solutions Corp wrote in 2022 that it had used A9 Green on numerous projects over the past 7 years, and that the company explained the best ways to get rebates while still meeting the required values. Kenwood Builders wrote in 2021 that it had worked with A9 Green on multiple new construction projects over the last few years. Its BBB grade is A+.