Sumzero has always been great to me! Dan, my technician, is the best. Always a pleasure to see and takes great care of us everytime. Highly recommend them to anyone

After getting quotes from a number of local contractors, we went with SumZero to install AC in our 1940's home, and we are so glad we did! They provided quotes (multiple options; ductless, central, hybrid, etc.) and detailed information quickly after visiting us, and were extremely responsive. They answered all our questions and helped us through every step, including the details for the MassSaves programs and rebates. When the time for install arrived, the team was professional, efficient, and incredibly thoughtful. We had a new baby at home, and they were so kind in working around us (and they even kept the noise to a minimum, without us asking!). The house was cleaned at the end of the work every night, and the final product was beautifully installed (any dings to paint were fixed, every register installed perfectly). The SumZero team showed great care and integrity, and we recommend them without reservation. Thank you, SumZero for a great experience and excellent work product!

Making the switch from an oil burning furnace to a cold weather heat pump to replace both our heating system and aging air conditioner was tough research to do on my own. Most all heating and oil companies around here did their best to spread old misconceptions about heat pumps only working well in the south where the winters are warmer, but there were so many articles improvements and technology That I decided to reach out to a company that specialized in heat pumps. David and his staff over at SumZero in Holliston were both excellent resources for information and professional in their quick estimates and work. It’s by no means a quick process from beginning to end with all the great incentive programs and related in work requirements, but again this is where David and his team made everything so clear and easy. Since the installation, their customer service has remained excellent to both answer one off questions I had about heat pumps which definitely work very differently from oil and gas furnaces to follow up appointments for quick inspections and a backup add-on installation. We are two winters and one summer into the installation and everything has worked out splendidly so far! Especially given oil and gas prices around here nowadays we are saving so much money having switched over!