🔒Energy firm Budderfly tops $1B in funding, launches battery storage rollout

If you ask Al Subbloie, founder and CEO of Shelton-based energy-as-a-service company Budderfly, the most effective way for businesses to cut utility costs is by avoiding energy use altogether. He calls it “spontaneous generation” — producing a kilowatt of energy by simply not consuming it. That concept underpins Budderfly’s business model. The company works with customers ranging from restaurants to manufacturers and universities to reduce energy consumption, generally lowering utility bills by as much as 30%, Subbloie said. “The world is struggling … to get energy to build data centers,” Subbloie said. “And we’re sitting here with the safest, easiest kilowatt you could ever have — the kilowatt you don’t need to use.” The company is now expanding beyond efficiency into energy storage, offering battery systems that allow customers to store unused power for later use. Budderfly is rolling out the storage option this quarter at 11 locations, including at Shelton manufacturer OEM Controls Inc. The expanded offering comes as Budderfly has recently secured additional financing and grown its intellectual property portfolio. On March 25, the company announced it expanded its debt facility to $550 million, including a $250 million increase led by Global Infrastructure Partners, part of investment giant BlackRock, with participation from existing lender Vantage Infrastructure. Budderfly said the latest financing, which will help fund energy efficiency upgrades at customer sites and support overall growth, brings its total capital raised to more than $1 billion. Meanwhile, earlier in March, Budderfly said it had 34 granted patents and 36 pending applications related to HVAC controls, distributed energy coordination and behind-the-meter microgrid management technology. In 2025 alone, it filed 21 new applications and was granted four patents, the highest annual total in its history. Subbloie, who founded Budderfly in 2017, said the company generated more than $250 million in revenue last year, helping it land on the Financial Times list of The Americas’ Fastest Growing Companies of 2026, where it ranked second among U.S. energy firms. “We’ve grown a lot,” he said during a recent interview with Hartford Business Journal.

‘Energy Lake’

Subbloie hopes customers will embrace his company’s latest offering, which it calls the “Budderfly Energy Lake.” The lake is actually a battery energy storage system made by Buffalo-based Viridi and installed by Budderfly at customer facilities. “Rather than give the saved kilowatt back to the utility, we put it into the lake,” Subbloie said.

Each of the medium-size batteries offers 150 kilowatt-hours of storage, roughly equivalent to 11 Tesla Powerwall batteries, the company said. At its peak, the “energy lake” can offer 30 kilowatts of power for five hours. Battery storage allows businesses to keep unused energy and use it during peak demand periods, when electricity is more expensive, helping lower costs and improve reliability. With the new offering, Budderfly is entering a fast-growing segment of the energy sector. The global battery energy storage market was valued at $32.62 billion in 2025 and is projected to reach $161.12 billion by 2034, driven by rising electricity demand, grid constraints and the need to store excess power from solar and wind, according to Fortune Business Insights. The industry includes both manufacturers and companies that install and manage storage systems. Tesla, for example, is a leading manufacturer, while Connecticut-based Cadenza Innovation is developing its own battery technology. Firms like Ellington-based Earthlight Technologies focus on installing and integrating systems — an approach more in line with Budderfly’s model. Subbloie said Budderfly is rolling out its battery installations in three phases. The first, already underway, will install batteries in 11 locations — OEM’s Shelton site, three commercial sites in Massachusetts and seven locations in California. Phase two will increase installations to 100 sites, while phase three calls for batteries to serve about 30% of Budderfly’s commercial portfolio of roughly 9,000 locations.

The business model

As part of Budderfly’s energy-as-a-service business model, the company assumes responsibility for clients’ utility spending and funds efficiency upgrades that reduce energy use by about 30%. It signs long-term contracts with customers and generates revenue through a share of the resulting energy cost savings. Budderfly installs equipment such as HVAC systems, air quality controls, LED lighting, smart panels, sensors and solar panels at no upfront cost, and provides around-the-clock, AI-enabled monitoring, maintenance and infrastructure upgrades. “Humans made equipment, lighting, things that are efficient, that need to be managed,” Subbloie said. “If you’re good at what you do, you can go get that 30%” savings. For OEM Controls, which employs about 200 people and has faced rising energy costs, Budderfly is investing $1.5 million in upgrades to the electronic controls manufacturer’s nearly 85,000 square feet of facilities in Shelton. In addition to installing battery technology, Budderfly has added LED lighting and a new water heating system, and replaced 90% of OEM’s rooftop solar system and 18 rooftop HVAC units.

Largest HVAC installer

Budderfly installs equipment in about 150 locations per month. “We’re putting in 400 commercial HVACs every month in the United States,” Subbloie said. “We are probably the largest installer of HVACs in the country right now.” He said the units save about 55% of the energy used by the systems they replace. Budderfly now has customers in all 50 states, and outsources about 80% of its installations, Subbloie said. The company still employs project managers and between 40 and 50 mechanical and electrical engineers. Budderfly has a Milford warehouse where it stores about 1,600 HVAC units, and even that building has been made net-zero for carbon emissions because it’s heated by geothermal energy. Subbloie said Budderfly has also focused heavily on developing its own technology and software. He said he previously tried to persuade Google to create a version of its residential Nest thermostat for commercial and industrial buildings, but when that effort fell short, “we created our own.” Budderfly also developed billing software that integrates with 600 utility companies nationwide, allowing it to manage energy billing for customers. “We patented that entire process,” Subbloie said. Budderfly has no plans to leave Connecticut despite its continued growth, Subbloie said. He expects staffing to increase by 10% to 20% annually, though not at the same pace as the company’s growth, in part because of improving use of AI tools. “The reason these big financial players are giving us so much money, it’s because they’re comfortable with where we’re going to put it, and we know the return we’re going to get from it,” he said.