How Coral helped SumZero recover hundreds of thousands in working capital
Case study
About SumZero
Founded in 2019 by David Sampaio and Ilija Crnobrnja, SumZero Energy Systems was built on the genuine belief that heat pumps are better for homes and better for the planet. While competitors were avoiding rebates or treating them as an afterthought, the Massachusetts-based business was leading with Mass Save rebates from day one.
The problem
Growth was creating a cash flow problem
However, growth brought a problem that was getting harder to ignore. Offering instant rebate discounts meant fronting the value upfront and waiting weeks, sometimes months, for reimbursement. With 90% of jobs going through Mass Save, that wait was compounding fast. While the business was growing, the rebate process was becoming a burden on cash flow, employees, and the time David and his team could have been spending on everything else.
The solution
That's when SumZero found out about Coral
Coral advanced the rebate funds the next day, took on the filing, the follow-ups, and the risk on every application. The effect was immediate. The working capital position that had been straining SumZero stabilized, their in-house team that had been buried in rebate processing got two full days a week back, and their contractors could keep offering instant discounts at the kitchen table, without the business carrying the cost of doing so.
If you're not offering $10,000 off and somebody else is, it's a no-brainer, it gives that competitive edge, for sure.”
David SampaioCo-Founder & CEO, SumZero
The solution
A partner, not just a platform
Beyond the financial impact, the people behind the platform also made the difference. Coral showed up as a genuine partner: accessible, responsive, and as invested in SumZero's success as they were.
“It gives a face to the name, which is really nice. Having Coral as a partner we can contact if we need them, like they’re an advocate for us, I can't explain how much that's appreciated.” — David Sampaio
2 days saved weekly
60% revenue increase
We were down hundreds of thousands of dollars at one point, which is when we heard of Coral. And we thought, ‘There's no way this is real.’ And it was real.
David SampaioCo-Founder & CEO, SumZero
The solution
Turn rebates from headache into opportunity
Since partnering with Coral, SumZero has grown from a sub-$5M business to $8-9M in annual revenue, with instant rebates playing a major role in that growth. Choosing Coral didn't just solve a cash flow problem. It removed the operational weight that comes with doing rebates at scale, and empowered SumZero to keep offering instant discounts without the cost and the headache that used to come with it.
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