In Connecticut, the energy efficiency industry is a fast-growing and dynamic one, as companies aim to create sustainable solutions to power our everyday lives. They provide services ranging from clean energy generation to energy storage and waste management. These firms are actively working to reduce our carbon footprint by offering renewable energy options and innovative technologies that enhance system performance. The future holds immense scope for these companies as environmental sustainability becomes not just a necessity, but a focal point for businesses and consumers alike. They are indeed paving the path to a greener, more sustainable future.


Top 23 energy efficiency companies in Connecticut

1. AVANGRID, Inc. (formerly UIL Holdings Corporation)

  • Website: avangrid.com
  • Headquarters: Orange, Connecticut, United States
  • Founded: 1852
  • Headcount: 5001-10000
  • LinkedIn

Avangrid is a leading clean energy company that generates and delivers energy from sustainable, renewable sources. They actively work to protect and enhance the natural environment.


2. HSB - Hartford Steam Boiler

  • Website: hsb.com
  • Headquarters: Hartford, Connecticut, United States
  • Founded: 1866
  • Headcount: 1001-5000
  • LinkedIn

Hartford Steam Boiler (HSB) is a company that specializes in energy efficiency, equipment breakdown, and equipment care. They provide loss-prevention tips and solutions for businesses and homeowners to avoid breakdowns and improve safety. With a focus on renewable energy and cybersecurity, HSB offers comprehensive services to protect and enhance the performance of electrical and air conditioning systems.


3. FuelCell Energy

  • Website: fuelcellenergy.com
  • Headquarters: Danbury, Connecticut, United States
  • Founded: 1969
  • Headcount: 501-1000
  • Latest funding type: Grant
  • LinkedIn

FuelCell Energy is a company that offers efficient and clean solutions for decarbonizing power and producing hydrogen. They provide platforms for distributed power generation, fuel cell platforms, solid oxide electrolysis, and energy storage. Their solutions cater to various industries such as power utilities, microgrids, industrial applications, transportation, buildings, and waste management. They also offer energy services and have a strong focus on carbon capture and tri-generation. FuelCell Energy aims to enable the transition to clean energy and contribute to a sustainable future.


4. Doosan Fuel Cell America, Inc.

Doosan Fuel Cell America is a leading global fuel cell company offering clean and quiet fuel cell products, solutions, and services. We partner with businesses to power a cleaner, energy-independent tomorrow. Our multi-tiered service options are tailored to meet the specific needs of our customers. We also provide government incentives and programs to promote the adoption of fuel cells and energize education on clean energy technology.


5. Viridian International Management

  • Website: viridian.com
  • Headquarters: Norwalk, Connecticut, United States
  • Founded: 2009
  • Headcount: 11-50
  • LinkedIn

Viridian is a company that offers products and services related to energy, environmental disclosures, and customer care. They provide solutions for individuals and businesses who are seeking environmentally friendly and sustainable options for their energy needs.


6. GameChange Solar

  • Website: gamechangesolar.com
  • Headquarters: Norwalk, Connecticut, United States
  • Founded: 2012
  • Headcount: 51-200
  • Latest funding type: Series Unknown
  • LinkedIn

GameChange Solar is a company that is changing the world by making solar energy affordable. They offer innovative solar racking systems and solutions to maximize solar energy production.


7. Steven Winter Associates

  • Website: swinter.com
  • Headquarters: Norwalk, Connecticut, United States
  • Founded: 1972
  • Headcount: 51-200
  • LinkedIn

SWA is a company that specializes in providing innovative energy efficiency, sustainability, and accessibility solutions for buildings. They offer services such as green building certification, energy optimization, and accessibility consulting for both residential and commercial construction projects. With a focus on improving the built environment, SWA has been in operation since 1972.


8. Tradition Energy

Tradition Energy is a company that helps businesses save money on energy costs through energy procurement and supply management. They provide market research, intelligence, and strategic energy risk management services. Tradition Energy also offers sustainability solutions and advises on green power purchases.


9. Energize Connecticut

  • Website: energizect.com
  • Headquarters: New Britain, Connecticut, United States
  • Founded: 1998
  • Headcount: 5001-10000
  • LinkedIn

EnergizeCT provides home and business energy solutions for Connecticut residents. They offer energy assessments, financing, and rebates for a variety of energy-saving improvements.


10. Budderfly

  • Website: budderfly.com
  • Headquarters: Shelton, Connecticut, United States
  • Founded: 2007
  • Headcount: 51-200
  • Latest funding type: Acquired
  • LinkedIn

Budderfly is an energy efficiency company that helps businesses modernize their facilities to be brighter, more comfortable, and more efficient. They offer a unique Energy Efficiency-as-a-Service solution, providing all the technology and investment in efficiency upgrades without any out-of-pocket costs. Their services include constant monitoring, maintenance, and upgrades such as LED lighting, HVAC systems, Budderfly IOT sensors, renewable energy sourcing, and more.


11. Greenworks Lending from Nuveen

  • Website: greenworkslending.com
  • Headquarters: Darien, Connecticut, United States
  • Founded: 2015
  • Headcount: 51-200
  • Latest funding type: Acquired
  • LinkedIn

Greenworks Lending is a company that offers financing solutions for energy efficiency projects. They specialize in C-PACE (Commercial Property Assessed Clean Energy) financing, which allows property owners to fund upgrades and improvements with no upfront costs. Their services include project types such as new construction, gut rehabs, energy efficient upgrades, solar and renewables, and recapitalization for recently completed projects. They also provide resources like case studies, available states, and FAQs. Greenworks Lending aims to make the world greener by providing loans for sustainable projects.


12. Eemax, Inc. (a Rheem Company)

  • Website: eemax.com
  • Headquarters: Waterbury, Connecticut, United States
  • Founded: 1988
  • Headcount: 51-200
  • Latest funding type: Acquired
  • LinkedIn

Eemax is America’s #1 manufacturer of energy-efficient, sustainable, innovative tankless electric water heaters, water heating boosters, and miniature tanks for residential, commercial, light industrial, and safety applications.


13. Automated Building Systems, Inc.

  • Website: absddc.com
  • Headquarters: Glastonbury, Connecticut, United States
  • Founded: 1986
  • Headcount: 51-200
  • LinkedIn

The company, ABSDDC, offers comprehensive energy efficiency services for commercial clients. They provide solutions for building automation, energy procurement, EV charging, HVAC energy improvements, LED lighting and controls, solar solutions, steam system optimization, and supermarket specialty programs.


14. The Spencer Turbine Company

Spencer Turbine is a company that offers innovative solutions in the field of turbine bypass systems and energy recovery systems. They specialize in providing customized solutions to power plants, helping them optimize their operations and reduce energy consumption. With their cutting-edge technology and expertise, they are committed to driving sustainability and efficiency in the power generation industry.


15. Louth Callan Renewables

Louth Callan Renewables develops, constructs, and maintains clean, renewable-energy projects in the United States, specializing in solar solutions. They offer workmanship warranties and operations and management agreements to ensure optimal functioning of the systems. LCR procures top-level equipment manufacturers and investment-grade panels for their projects.


16. Verdek

  • Website: verdek.com
  • Headquarters: Madison, Connecticut, United States
  • Founded: 2008
  • Headcount: 11-50
  • LinkedIn

Verdek Green Technologies Corp. is a leading solution-driven company that specializes in electric vehicle charging and CNG/LNG infrastructure for sustainable transportation. They offer EV charging stations, CNG/LNG products, virtual pipeline solutions, and turnkey solutions. Their innovative technologies help reduce greenhouse gas emissions and provide clean energy solutions. They serve a wide range of customers, including fleets, ferries, tug boats, trains, and more. Verdek is committed to delivering high-performance products with a small footprint and lower operating costs compared to traditional LNG plants.


17. Counterpointe Sustainable Real Estate LLC

  • Website: counterpointesre.com
  • Headquarters: Greenwich, Connecticut, United States
  • Founded: 2014
  • Headcount: 11-50
  • Latest funding type: Series C
  • LinkedIn

CounterpointeSRE is a company that focuses on sustainable energy finance and provides capital for renewable energy production and energy efficiency projects in commercial buildings. They specialize in financing the construction of new 'greener' buildings and the retrofit of existing properties, directly addressing climate change and bringing efficiency and renewable measures to residential and commercial buildings.


18. Green Energy Solutions

Green Energy Solutions is an energy conservation implementation company that offers cost-effective solutions to businesses for reducing energy usage and improving efficiency. They specialize in upgrading existing equipment in areas such as lighting, refrigeration, HVAC, and solar technologies. With a focus on practical applications and the best return on investment, they strive to provide long-lasting solutions that require minimal capital investment. Their turnkey operation includes product installation, maintenance, and warranty services.


19. Green Star Energy Solutions

Go Green Star is a company that offers energy assessments, audits, and various energy solutions including heat pump technology, new construction design and build, and commercial and multifamily energy programs.


20. Greenleaf Energy Solutions

Greenleaf Energy Solutions is a commercial energy efficiency company that offers practical solutions to meet your energy, environmental, and social ideals. They provide complimentary energy assessments, interest-free project financing, and expertise in utility rebates. Their services include lighting assessment, retrofitting, renewable energy solutions, and mechanical & HVAC solutions.


21. JKMuir

  • Website: jkmuir.com
  • Headquarters: Rocky Hill, Connecticut, United States
  • Founded: 2008
  • Headcount: 11-50
  • LinkedIn

JKMuir is an engineering firm specializing in the integration of sustainability and clean energy into public infrastructure projects. They provide design, construction, and consulting services to drive renewable energy generation and minimize carbon impacts. Their expertise includes energy management, pump system efficiency, sustainability, and decarbonization.


22. Stanwich Energy Advisors LLC

Stanwich Energy is a trusted energy management company that offers comprehensive energy solutions to private and public organizations in the US. They leverage their expertise and market tracking technology to help organizations buy and consume energy smarter, reduce costs, and optimize energy consumption. With a focus on efficiency and reliability, they provide tailored solutions to meet the unique needs of their clients across industries.


23. Evolutionary Home Energy Solutions

Evolutionary Home Energy is a provider of energy-efficient home improvement solutions and technologies, including solar energy systems and efficient home insulation.


Want to find more energy efficiency companies?


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