Best Energy Tech Companies in Connecticut, United States
The 51 best Energy Tech companies in Connecticut, United States in 2026, ranked by funding and momentum. Funding, investors, founders, valuation, tech stack and live signals. Top: Budderfly.
Our analysis of 79 Energy Tech companies
$38.9b in tracked funding; 92% of the stack-profiled cohort runs cloud-native; funding activity peaked in 2025.
Ranked: Best Energy Tech companies in Connecticut
| # | Company | Disclosed funding | Last round | Stage | Founder | Founded | Tech stack | Patents & IP focus | Recent signals |
|---|---|---|---|---|---|---|---|---|---|
| 1 | Budderfly Provider of energy management solutions and services for buildings 76Innovation top 19%Patents top 19%Funding top 22%Growth top 27% All 11 signals ▾Innovationtop 19% Patentstop 19% Fundingtop 22% Growthtop 27% Newstop 30% Moattop 32% Producttop 33% Techtop 41% Talenttop 41% Marketbottom 49% Globalbottom 36% Innovation: 68 patents (top 23% of patent-holders) · 43 filings since 2022 vs 9 in 2017-21 Patents: 68 patents matched (strict assignee match) · 43 filings since 2022 vs 9 in 2017-21 rank vs industry peers · Fliar Intelligence Index 76/100 | $85M | 4 mo ago | Acquired | Al Subbloie Founder & CEO | 2007 | HubSpot CMS HubApple iCloud MailZoho+29 | 68 patents IoT-enabled energy management and efficiency technologies for industrial/commercial power systems | 2 partnerships |
| 2 | Proton OnSite Makes gas generator system | $46M | 15 mo ago | Acquired | — | 1996 | — | — | — |
| 3 | Saphlux Developer of III-V Group-based semiconductor materials 40Talent top 15%Product top 25%Funding top 30%Moat top 32% All 9 signals ▾Talenttop 15% Producttop 25% Fundingtop 30% Moattop 32% Patentstop 38% Innovationtop 40% Techbottom 44% Globalbottom 40% Marketbottom 20% Talent: Analyst team rating 5/5 Product: 6 distinct product lines · Company stage: Series C rank vs industry peers · Fliar Intelligence Index 40/100 | $22M | 3 mo ago | Series C | — | 2014 | Cart FunctionalitySquarespace CommerceSquarespace+13 | 32 patents Patents concentrated in electrical & electronics | 1 partnership |
| 4 | Cadenza Innovation Lithium-Ion-based battery system developers | $20M | 22 mo ago | Series A | Christina Lampe-Onnerud Founder and CEO | 2016 | WordPressMySQLPHP+20 | 100 patents Advanced lithium‑ion battery storage systems with safety, low‑profile disconnects, and carbon‑responsive control | — |
| 5 | Dexmet Expanded metal and foil solutions for diverse engineering applications | $16M | 160 mo ago | Acquired | Tim Poor CEO | 1948 | — | 5 patents Lightning protection systems using ultra‑thin metallic foils and composite conductive structures. | 1 partnership |
| 6 | Solais Lighting Manufacturer of smart LED lighting products | $9M | 78 mo ago | Acquired | Samuel Newberry CEO & President | 2008 | WordPressMySQLPHP+37 | 15 patents High‑efficiency LED lighting modules, drivers, and power‑supply conditioning for improved visual performance. | 1 launch |
| 7 | Noteworthy Offering cloud and AI-driven power line inspection solutions | $9M | 33 mo ago | Series A | — | 2020 | — | — | — |
| 8 | Oasis Charger Corporation Manufacturer of electric vehicle chargers | $7M | 65 mo ago | Series A | Paul Vosper CEO | 2018 | — | — | — |
| 9 | ZoneFlow Reactor Technologies Innovating steam methane reforming for efficient hydrogen production and carbon capture | $5M | 105 mo ago | Seed | — | 2014 | — | 58 patents Patents concentrated in mechanical & energy engineering | — |
| 10 | SRS Provider of a platform for commercial property assessed clean energy programs | $4M | 151 mo ago | Seed | — | 2010 | — | 117 patents Real-time audio signal processing, adaptive object streaming, and immersive sound rendering | — |
| 11 | DashFuel Provider of the petroleum distribution platform | $3M | 37 mo ago | Series A | Miles Moen Co-Founder & CEO | 2022 | WordPress Block EditorWordPressMySQL+18 | — | — |
| 12 | Sustainable Real Estate Solutions Software for calculating energy saving as financial impacts | $3M | 166 mo ago | Seed | Brian McCarter CEO | 2010 | — | — | — |
| 13 | Raise Green Developer of a crowdfunding platform for renewable energy and climate solution projects | $2M | 37 mo ago | Seed | Jackie Logan CoFounder | 2011 | — | — | — |
| 14 | Enviro Power Online platform offering HVAC monitoring solutions | $2M | 38 mo ago | Series A | — | 2013 | — | — | — |
| 15 | Avalence Provider of electrolytic hydrogen fuel generators | $1M | 190 mo ago | Funding Raised | Deborah Moss Founder & Principal | 2002 | — | 9 patents Advanced pressure and liquid-level control systems for hydrogen electrolyzers | — |
| 16 | Skyre Develops and manufactures products for energy and other industries | $380K | 99 mo ago | Seed | Trent M. Molter Founder | 2007 | Cart FunctionalitySquarespace CommerceSquarespace+11 | 74 patents Electrochemical gas separation and production systems for H₂, O₂, and CO₂ | — |
Top 12 Energy Tech companies in Connecticut
#1
Acquired · Shelton, Connecticut · founded 2007 · 103 employees$84.8Mraised▾
Provider of energy management solutions and services for buildings. It provides integrated light switches to monitor and control lighting loads, advanced power strips to monitor and control plug load at the workstation level, temperature sensors, and electrical panel-level monitoring devices to monitor load at each level and report back to central software. It caters to corporations, municipal governments, colleges, universities, and manufacturers.
- Mar 2026Conventional Debt$550M
- Jun 2025Conventional Debt$100M
- Jan 2024Conventional Debt$400M
- Oct 2020Series B$7.8M
#2
Series C · New Haven, Connecticut · founded 2014 · 3 employees$22Mraised▾
Developer of III-V Group-based semiconductor materials. It provides users with III-V Group-based semiconductor materials for fabricating semiconductor wafers or integrated circuits with a new base material which finds applications in improving LED technology and LED performance. It also provides a chip out which could reduce the cost of manufacturing LED-based lighting by 10 times.
- Apr 2026Series C$43.5M
- Dec 2022Series B$15.8M
- Mar 2017Series A$5M
- Jul 2015Seed$200K
#3
Acquired · Wallingford, Connecticut · founded 1996 · 144 employees$45.6Mraised▾
Proton OnSite manufactures hydrogen, nitrogen, and zero air generators. The company also develops proton exchange membrane (PEM) electrolysis systems that support gas generation units. Proton OnSite server U.S. military, aerospace, fueling, and renewable energy industries.
- Apr 2025Grant (prize money)$4.9M
- Mar 2020Grant (prize money)$1.9M
- 2016Grant (prize money)$841.2K
- 2015Grant (prize money)$150K
#4
Series A · Oxford, Connecticut · founded 2016 · 28 employees$20.3Mraised▾
Lithium-Ion-based battery system developers. It is a provider of energy storage solutions based on architectures for lithium-ion battery packs. The company claims that its cell design combines the best properties of wound jelly rolls and large prismatic cells and allows for high energy density at low cost for EV, PHEV, and grid markets.
- Oct 2024Conventional Debt$2.8M
- Oct 2022Series A—
- Feb 2022Series A$5M
- Feb 2021Series A$3.4M
#5
Series A · Stamford, Connecticut · founded 2020 · 5 employees$8.6Mraised▾
Offering cloud and AI-driven power line inspection solutions. Its sensors can be mounted on vehicles for real-time asset inspection. It offers Inspector Edge which uses existing fleet vehicles to inspect and inventory assets in the field, and Inspector Cloud which provides analytics solutions.
- Oct 2023Series A$5.6M
- Jul 2022Seed$3M
- Jun 2021Seed$1.9M
#6
Series A · Norwalk, Connecticut · founded 2022 · 8 employees$3.2Mraised▾
Provider of the petroleum distribution platform. It offers solutions such as workflow management, real-time syncing, digital invoicing, and more.
- Jun 2023Series A$3.2M
#7
Seed · New Haven, Connecticut · founded 2011 · 9 employees$2.2Mraised▾
Developer of a crowdfunding platform for renewable energy and climate solution projects. It provides equity-based crowdfunding platforms where people can invest in oil-and-gas-related ventures. Its features include a list of projects like electric vehicle infrastructure, diesel generator replacements, microgrids, and solar projects.
- Jun 2023Seed$1M
- Oct 2022Seed$1.2M
- 2021Seed$20K
- Feb 2019Grant (prize money)$10K
#8
Acquired · Stamford, Connecticut · founded 2008 · 42 employees$9.4Mraised▾
Manufacturer of smart LED lighting products. Their proprietary technology features Luxiance thermal management and technology which enhances the performance compared to normal LED lighting products. Offers products under two brands SOLARIS which includes track lights, linear wall fixtures, recessed downlights, LED lamps, track systems, and others, and ENERGYLITE which includes roadway lighting, floodlighting, security lighting, billboard lighting, and others. The products are integrated with dimming features and different types of sensors. Solais LED products are used in retail, commercial, museum, and hospitality environments.
- Jan 2020Series B$5.3M
- Nov 2011Series B$1.8M
- Dec 2009Series A$2.3M
- Dec 2009Series A$638K
#9
Series A · East Hartford, Connecticut · founded 2018 · 26 employees$7Mraised▾
Manufacturer of electric vehicle chargers. The company designs and develops chargers for the electric vehicle market. The company is also called as JuiceBar EV.
- Feb 2021Series A$6.5M
- Feb 2021Seed$450K
- Aug 2019Seed—
#10
Acquired · Wallingford, Connecticut · founded 1948 · 66 employees$16Mraised▾
Expanded metal and foil solutions for diverse engineering applications. They provide highly configurable expanded and perforated materials, including metal foils and polymers, tailored to meet specific application requirements. Their solutions cater to dimensional, conductivity, weight, or strength demands. They offer expanded metal solutions widely used in aerospace, electrochemical, medical, and automotive industries. Expanded polymer solutions are used in advanced filtration systems, particularly in the semiconductor, medical, gas, and oil industries. They provide materials for electrodes in primary and secondary battery applications, fuel cells & hydrogen electrolyzers, aircraft & wind blade lightning strike protection, filtration, thermal management, EMI/RFI shielding, and hi-temp gaskets and bushings. They focus on precision, high-quality, and repeatable products.
- Mar 2013Conventional Debt$16M
#11
Series A · Hartford, Connecticut · founded 2013 · 24 employees$1.5Mraised▾
Online platform offering HVAC monitoring solutions. It provides onsite energy storage, backup power, and a boiler. It uses an integrated electric generator in a water boiler.
- May 2023Series A—
- Oct 2019Series A$1.5M
#12
Seed · Windsor, Connecticut · founded 2014 · 11 employees$4.8Mraised▾
Innovating steam methane reforming for efficient hydrogen production and carbon capture. This company focuses on revolutionizing hydrogen production through advanced steam methane reforming (SMR) technologies. They offer solutions to dramatically improve the efficiency of hydrogen production from hydrocarbons. Their key offerings include structured catalysts and processes designed to capture carbon emissions from the SMR process. These technologies can be retrofitted to existing SMR plants. They collaborate with industry leaders to bring innovative solutions to the market. The company is dedicated to developing new technologies for recuperative reforming and integrating renewable energy into the SMR process, contributing to a cleaner hydrogen economy. Their focus is on providing cost-effective and environmentally responsible solutions for hydrogen production.
- Oct 2017Seed$276K
- Nov 2016Seed$562.5K
- Aug 2015Seed$750K
- Dec 2014Seed$3.2M
Funding & investor landscape
Notable founders
Market landscape — 10 sub-themes by coverage
Share of Energy Tech coverage by sub-theme.
Regulatory-risk over time rising
Funding & growth over time
funding rising · growth rising
What Connecticut researches in energy storage
- University of Connecticut20
Common questions
Rohit lives in the feed. He covers what's moving right now — the funding rounds, launches and shifts breaking across the trade press — and ties them back to where the sector is heading.