SumZero Energy Systems

If we could give SumZero Energy 6 stars, we would! We found them via an email outreach they did, and from the very first contact all the way through final installation and tech check, we can't rave enough about this company. Raphael, our sales rep, was excellent with superb communication and follow-up. Likewise, Paulo and his installation crew were polite. knowledgeable, hard-working, and a pleasure to deal with. Even the staff at the main office has excellent communications skills and follow through. Top to bottom, SumZero works extra hard to meet your needs and make you happy. They even guided us to make sure we got the maximum rebates allowed. We chose a Mitsubishi heat pump system and are very happy with it so far. It's a big technology leap for us but we are confident that the SumZero team will make sure that our first winter/summer seasons go smoothly. Do not hesitate to hire this company! Tom & Joanne, Belmont, MA

I’ll start off by simply saying my experience with SumZero Energy Systems could not have been better and surpassed all my expectations. My initial consultation with their energy consultant went well and totally inspired my confidence in their ability to get the job done. The price was fair, even a little less than other estimates I received. Paul, my SumZero energy consultant had four separate estimates delivered to me covering various configurations of the mini-split system to me within a day after our meeting. Paul explained the technical side of this technology to me very clearly and made it easy to understand. He also explained the advantages of using the Mass Save energy rebate program to lower installation costs upgrade insulation in my home. The savings through the Mass Save program is amazing. The actual installation of the mini-split system went off without out the slightest problem. The crew showed up promptly on time and got right to work. They were polite, efficient and obviously experts at this process. The were extremely conscientious about laying out taps in the house in their work areas and the the place spotless. They were a stellar crew! My wife and I could not be happier. Now that the warm weather is here I’m taking full advantage of the mini-split system. It’s whisper quiet, super efficient and looks great. The bonus is I don’t have to lug and install the bulky and heavy AC window units ever again. YAY! If the rating system is 1 through 10, with 10 being the best, I’d give SumZero an 11. Look no further, hire SumZero for you mini-split installation. You will not be disappointed.

After getting 4 quotes we decided to work with Sum Zero for the installation if a whole home heat pump system. Their customer service is grade A, from sales to support with heat loan and rebate filing. They invited us to visit their show room to learn more about the company and technology, and were very flexible and responsive as we asked for different iterations of quotes as we tried to figure out what would really be the right solution for us. I was very sensitive to the aesthetics inside and out, and they helped us to come up with a solution that addressed this. The installation was quick in only 2 days for two heat pumps and 5 indoor registers. The crew was incredibly tidy and the installation is very clean and professional. They spread coverings over everything in the vicinity of the work and vacuumed at the end of each day. Couldn’t ask for more.

What an AMAZING team they have. From the receptionist, the estimate, the installers, the follow ups, and the smallest thing that was not perfect for us — they came right away and fixed/adjusted it. SUPER COMPANY with real people who care about their customers and not just the money. They were not the cheapest nor the most expensive. You just can not go wrong. * They installed a dual zone Mitsubishi mini-split system for us early this year (2023) * THANK YOU — highly recommend!

We had a great experience with SumZero. They were recommended by a friend who had a great experience. We worked with Raphael who came out, looked at everything and went through options for our furnace/heat pump and AC upgrade. We received a detailed proposal including available rebate programs through MassSave. We had 3 other estimates but decided to go with SumZero. The installation team came out reviewed everything at our home and a couple of days later the team arrived and installed everything in one day. Clean-up was great. The system is running perfectly and we couldn’t be happier. They also handled much of the paperwork of the rebate program- which was a huge added bonus. Highly recommend.

Sum Zero did a great job installing whole-house mini splits. When we had concerns about the location of line sets at the last minute, they redrew the plans (over a weekend) and shifted to floor mount units to make the lines easier to deal with. The installation crew was hard-working, careful, and considerate. We are pleased with the installation. UPDATE: Three months after the installation, we are having significant trouble keeping our house at the right temperature. We are trying to engage with Sum Zero to fix the problems. I will update this review when it becomes clearer whether Sum Zero has provided satisfactory service after the installation.

We just had SumZero do a full conversion for our home to heat pumps for heating and cooling. We had a lot of questions and worries about how this would go. From the first consultation SumZero was fast, responsive, and thoughtful in planning this project. They walked us through everything. Installation took only 2 days and the team was excellent and professional. I'm now sitting in a cool, quiet house without window units! They went above and beyond and we are super grateful to them. Highly recommend.

This company and the 2 reps (Daniel and Alex) have been fantastic in explaining the use of the mini split units and their capabilities. They serviced my 2 units and Daniel came back to repair one. Daniel also installed a temp control thermostat that I think will be super helpful in keeping the house warm in the winter. I’m thrilled with the service. They are very professional and even wear booties for walking around your house!