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Meet the Team Behind the Mission

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Our Company
Our Leadership

Our Leaders

At SumZero, we don’t believe in titles for the sake of hierarchy — we believe in leadership that serves. The people below don’t just oversee operations — they solve problems, build teams, and protect the promises we make to customers.

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From the office to the warehouse to the field, these are the faces you can count on — the people who help make SumZero one of the most trusted heat pump companies in Massachusetts.

Leadership Team

Co-Owner
David Sampaio

David Sampaio

Co-Owner

Field-focused, results-driven, and committed to excellence on every project.

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Co-Owner
Ilija Crnobrnja

Ilija Crnobrnja

Co-Owner

Vision-led leader guiding our mission, marketing, and customer experience.

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Comfort Consultant
Paul Jameson

Paul Jameson

Comfort Consultant

Listens deeply, designs smart, and helps customers make informed decisions.

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Comfort Consultant
Raphael Guimaraes

Raphael Guimaraes

Comfort Consultant

Brings clarity and trust to every estimate — a straight-shooter and system thinker.

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Finance Manager
Keven Xavier

Keven Xavier

 Finance Manager

Keeps our books tight and our strategy sharp. Numbers with integrity.

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Executive Assistant & HR Manager
Marjory Ramos

Marjory Ramos

Executive Assistant & HR Manager

The glue behind the scenes — organized, dependable, and deeply caring.

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Project Manager
Jackson Carvalho

Jackson Carvalho

Project Manager

Makes the job flow — clear scheduling, clear expectations, and no loose ends.

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Warehouse Manager
David Teran

David Teran

Warehouse Manager

Keeps our gear, our people, and our inventory moving smoothly every day.

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Install Coordinator & Call Center Lead
Lara Cosendey

Lara Cosendey

Install Coordinator & Call Center Lead

Juggles logistics with heart — a calm voice and steady hand behind the scenes.

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Mass Save® & AR Coordinator
Sarai Kerr

Sarai Kerr

Mass Save® & AR Coordinator

Keeps the rebate process moving and the details buttoned up.

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Curious what it’s like to work with people who actually live by these values?

Want to learn more about the areas we serve? Discover our service area and see how close we are to helping you.
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Curious what it’s like to work with people who actually live by these values?
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What Local Homeowners Are Saying

See how SumZero has helped local homeowners stay comfortable year-round with energy-efficient heat pump solutions.

Dan the service tech was awesome and the best. Also SumZero HVAC company and all of the employees are the best as well. I would highly recommend them
Jonah Epstein
Sumzero energy systems is nothing but professional, these guys come in and provide great service, have great work ethic and get the job done right. Very happy with the results.
Kevin Tomasetti
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!
Maria Arakil

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