SumZero Energy Systems

Working with David on replacing my dead 20-yr-old gas furnace, and working but similarly-aged AC was productive. Took a bit of work agreeing to what exactly needed to be done but, eventually, the installation was smooth and nicely done. And fairly priced too.

David and Ilija seem like a bunch of young and energetic owners, very capable of handling relatively straightforward jobs like full replacements. The entire job was completed in one day. Hopefully nothing else will break in my house but, if it does, SumZero will be the first company I'll reach out to.

I was extremely happy working with SumZero. When my AC stopped working on a hot summer night I called SumZero and they were at my door the next day. They provided me with high quality heating/ac equipment at a very affordable price. They were very professional and completed the job in a timely manner. They were very responsive, understanding to my needs, and worked with me to get exactly what I was looking for. There’s no one else I would ever use! Highly recommend

I live in an older home built in the early 20th century and heating and cooling has always been an issue. I figured upgrading to a modern system would be the best decision for me and my family but wasn’t sure how to go about it. I contacted SumZero and they took me through the whole process and had a very comprehensive approach to my home and efficiency. I was super happy and pleased with the retrofit and the end result was perfect. The guys here were very professional, polite, and helped educate me on how to make my home more efficient. Definitely consider SumZero if you’re looking to upgrade your old system.

My wife and I bought a house that had oil heating baseboards and windows AC. We called a few companies to get a quote to replace to central air, but once we talk to SumZero the choice was clear. IIija was very professional and friendly. He explained the entire system and process to us as clear as it gets. He guided us to a system that would accommodate all of our needs. From that moment on I have to say the customer service was beyond expectations. His team was very professional and did an amazing job. They explained me how everything works. We couldn’t asked for more. Definitely would recommend anyone who wants great service call SumZero. They know how to treat a customer. Thanks IIija and the entire SumZero team.

I can't say anything bad about this company. We just recently had some Spray Foam insulation done at our house and we could not be more than pleased of the job that was done. David and Ilija are amazing guys that understand the needs for your house! Paul was a professional as well as he did the Spray Foam in a few hours. SumZero is efficient, the people there are amazing, and they don't break your pocket either! I will definitely be contracting them again.

David and Wandersen have an amazing team! I have never worked with a more professional, knowledgeable and courteous team before. Every single person that works with Sum Zero was impressive. They were willing to answer all of our questions, provide accurate quotes and were always open to additions as the jobs moved forward. I welcomed them in my home for a week and a half of work and would do so again in a heartbeat. You cannot go wrong with hiring Sum Zero!

Top Notch. Most professional and caring group of contractors I have ever worked with. They go out of their way to make your experience a good one, they treat your home like it is theirs. I even overheard their electrical sub contractors commenting on how nice it it to work with SumZero. We had a ductless A/C installed for a good price with exceptional speed and service.

Paul was super knowledgeable when he came to give us a quote, and both he and Sarai were always quick in communicating. It didn't take long for us to get on the schedule and they handled everything with MassSave which took a lot of work off our shoulders. The installation team did a fantastic job, were very efficient and tidy, and we finally have some relief from this summer heat. Would absolutely recommend.

Zero sum energy has installed a new heating system and spray foam for my family. What a difference!! David and his guys are always very reliable and professional. I would highly recommend them to anyone in need of HVAC services.

A wonderfully professional team from beginning to end. David, the salesperson, was knowledgeable and clear in his explanation of the Mini-Split system. The installation team took extreme care to keep our house tidy, installing the system on a rainy day. They put down tarps throughout the house and they cleaned up completely, indoors and out. This company is clearly a customer-oriented group, eager to do quality work and to communicate with the homeowner. I'd give them six stars if I could!