Company lists · Data refreshed September 2026

Top 25 Energy efficiency contractors worldwide

RevenueBase identified 7,333 energy efficiency contractors worldwide as of September 2026 and tracks 83,036 professional contacts across them, including 30,358 with verified work emails and 0 with mobile numbers. The United States is the largest market and Paris the largest hub.

This list covers energy efficiency contractors worldwide, matched on what each company actually does as described in its own words. Ranked by team size, largest first. Every row shows the company's own description, its RevenueBase Smart Search rating, and when it was last checked. Data refreshed September 16, 2026. Country and city lists for energy efficiency contractors follow the table.

Published by RevenueBase, a B2B data infrastructure company. This list was built with RevenueBase Smart Search, the natural-language company search RevenueBase customers use to build their own targeted lists and unlock verified emails and direct dials at the companies on them. How these lists are built and judged.

How to read this list HQ checked on every row RevenueBase Smart Search rating on every row Refreshed Sep 16, 2026 86% judged on-target in blind review
7,333Companies
83,036Contacts tracked
30,358Verified emails
0Mobile numbers
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The 25 largest energy efficiency contractors worldwide

Ranked by team size
Top 25 of 7,333 energy efficiency contractors worldwide, ranked by team size, largest first. Data refreshed Sep 16, 2026. RevenueBase Smart Search rates how each company's information relates to energy efficiency contractors: strong evidence (its own description names it), partial (names part of it), indirect (matched on the rest of its profile rather than the description shown). Click a contact count to view that company's people.
#CompanyRevenueBase Smart SearchHeadquartersEmployeesContacts
1Indirect evidenceWindsor, United KingdomHQ checked Sep 16, 202610001+9,238 contacts →

Indirect evidence

“Taking care of things.”

Source: RevenueBase Database · checked Sep 16, 2026
2Indirect evidenceSaint-andré-lez-lille, FranceHQ checked Sep 16, 202610001+8,427 contacts →

Indirect evidence

“Dalkia : ensemble, relevons le défi climatique!”

Source: RevenueBase Database · checked Sep 16, 2026
3Strong evidenceAustin, TX, United StatesHQ checked Sep 16, 20261,001-5,0002,121 contacts →

Strong evidence

“CLEAResult is the largest provider of energy efficiency, energy transition and energy sustainability services in North America.”

Source: RevenueBase Database · checked Sep 16, 2026
4Partial evidenceFramingham, MA, United StatesHQ checked Sep 16, 20261,001-5,0001,383 contacts →

Partial evidence

“Ameresco, Inc.(NYSE:AMRC) is a leading energy infrastructure solutions provider dedicated to helping customers reduce costs, enhance resilience, and decarbonize to net zero in the…”

Source: RevenueBase Database · checked Sep 16, 2026
5Indirect evidenceOslo, NorwayHQ checked Sep 16, 20261,001-5,0001,150 contacts →

Indirect evidence

“GK er en ledende teknisk entreprenør og servicepartner.”

Source: RevenueBase Database · checked Sep 16, 2026
6Indirect evidenceAnaheim, CA, United StatesHQ checked Sep 16, 20261,001-5,000851 contacts →

Indirect evidence

“Willdan (NASDAQ: WLDN) provides professional consulting and technical services to utilities, public agencies and private industry throughout the United States.”

Source: RevenueBase Database · checked Sep 16, 2026
7Partial evidenceWestborough, MA, United StatesHQ checked Sep 16, 2026201-500481 contacts →

Partial evidence

“NORESCO, a part of Carrier Global Corporation, helps customers modernize aging building systems and upgrade energy and water infrastructure to meet evolving demands.”

Source: RevenueBase Database · checked Sep 16, 2026
8Partial evidenceAubervilliers, FranceHQ checked Sep 16, 20261,001-5,000460 contacts →

Partial evidence

“Veolia Industries Global Solutions est devenu Veolia Energie Performance depuis le 1er juin 2025.”

Source: RevenueBase Database · checked Sep 16, 2026
9Partial evidenceIrvine, CA, United StatesHQ checked Sep 16, 2026201-500383 contacts →

Partial evidence

“We are Trio – built from Edison Energy, Alfa Energy, and Altenex Energy.”

Source: RevenueBase Database · checked Sep 16, 2026
10Strong evidenceShelton, CT, United StatesHQ checked Sep 16, 2026201-500366 contacts →

Strong evidence

“Budderfly is redefining how energy efficiency, resilience, and grid participation can work together across America’s commercial sector.”

Source: RevenueBase Database · checked Sep 16, 2026
11Indirect evidenceLyon Cedex 7, FranceHQ checked Sep 16, 2026501-1,000366 contacts →

Indirect evidence

“Depuis près de 25 ans, HomeServe accompagne les particuliers vers une maison plus durable, plus sûre et plus économique.”

Source: RevenueBase Database · checked Sep 16, 2026
12Strong evidenceMedford, MA, United StatesHQ checked Sep 16, 2026201-500356 contacts →

Strong evidence

“At HomeWorks Energy, our mission is simple, literally: Energy Efficiency, Simplified.”

Source: RevenueBase Database · checked Sep 16, 2026
13Indirect evidenceCourbevoie, FranceHQ checked Sep 16, 2026201-500318 contacts →

Indirect evidence

“En 2019, le Groupe EDF veut rendre la vie des Français plus simple et lance IZI by EDF, sa plateforme pour accompagner ses clients vers la transition énergétique.”

Source: RevenueBase Database · checked Sep 16, 2026
14Indirect evidenceClichy, FranceHQ checked Sep 16, 2026201-500293 contacts →

Indirect evidence

“Engagé depuis 2008, Hellio est le pionnier du marché des économies d’énergie en France (métropole et Outre-Mer).”

Source: RevenueBase Database · checked Sep 16, 2026
15Partial evidenceParis, FranceHQ checked Sep 16, 2026201-500292 contacts →

Partial evidence

“Effy, spécialiste de l’efficience énergétique.”

Source: RevenueBase Database · checked Sep 16, 2026
16Partial evidencePortland, OR, United StatesHQ checked Sep 16, 2026201-500288 contacts →

Partial evidence

“At Cascade Energy, we believe in better.”

Source: RevenueBase Database · checked Sep 16, 2026
17Partial evidenceJuiz De Fora, BrazilHQ checked Sep 16, 2026201-500280 contacts →

Partial evidence

“A DEODE Energia foi fundada em 2012 proveniente da HF Energy.”

Source: RevenueBase Database · checked Sep 16, 2026
18Strong evidenceFort Washington, PA, United StatesHQ checked Sep 16, 2026201-500252 contacts →

Strong evidence

“CMC Energy Services is a woman-owned full-service energy efficiency company with nearly 50 years of experience delivering value-based energy conservation services.”

Source: RevenueBase Database · checked Sep 16, 2026
19Indirect evidenceQuébec, QC, CanadaHQ checked Sep 16, 2026201-500238 contacts →

Indirect evidence

“At Ecosystem, we believe in building meaningful relationships with both our clients and employees.”

Source: RevenueBase Database · checked Sep 16, 2026
20Indirect evidenceNew York, NY, United StatesHQ checked Sep 16, 2026201-500233 contacts →

Indirect evidence

“As of November of 2025, AMA Group has merged with CMTA!”

Source: RevenueBase Database · checked Sep 16, 2026
21Partial evidenceNewark, NJ, United StatesHQ checked Sep 16, 2026201-500233 contacts →

Partial evidence

“Lime Energy is building a new energy future.”

Source: RevenueBase Database · checked Sep 16, 2026
22Partial evidenceDartmouth, NS, CanadaHQ checked Sep 16, 202651-200230 contacts →

Partial evidence

“EfficiencyOne is a leading efficiency expert.”

Source: RevenueBase Database · checked Sep 16, 2026
23Partial evidenceSao Paulo, BrazilHQ checked Sep 16, 202651-200225 contacts →

Partial evidence

“Empresa voltada a projetos de Otimização e Eficiêntização no uso da energia elétrica.”

Source: RevenueBase Database · checked Sep 16, 2026
24Strong evidenceJaipur, IndiaHQ checked Sep 16, 202651-200217 contacts →

Strong evidence

“Design2Occupancy Services LLP (D2O) is a leading organization providing a platform and solutions in Energy Efficiency Analysis and Energy Code Compliances, Climate Change…”

Source: RevenueBase Database · checked Sep 16, 2026
25Strong evidenceDetroit, MI, United StatesHQ checked Sep 16, 202651-200216 contacts →

Strong evidence

“Walker-Miller Energy Services (Walker-Miller), one of the largest African American and woman owned energy efficiency companies in the United States, changes lives through energy.”

Source: RevenueBase Database · checked Sep 16, 2026

Showing 25 of 7,333 energy efficiency contractors worldwide

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Energy efficiency contractors worldwide at a glance

As of Sep 16, 2026
36.6%Verified-email coverage
11.3Average contacts per company
1-10Median size (employees)
1.7%Largest-city concentration · Paris
Sep 16, 2026Page data refreshed

Companies by employee count

1-10
4,332
11-50
2,306
51-200
511
201-500
94
501-1,000
17
1,001-5,000
14
5,001-10,000
1
10001+
4

How this list was built

Company categories are rarely black and white. RevenueBase reads each company's own description of its business to decide whether it belongs among energy efficiency contractors, so some rows will be adjacent to the category rather than pure plays. The description and RevenueBase Smart Search rating on every row are there so you can check each match yourself.

Source
The RevenueBase company graph: 60 million companies and 398.9 million professional contacts resolved from primary sources, queried with RevenueBase Smart Search, the natural-language company search available to every RevenueBase user.
Coverage
25 countries, largest first: the United States, France, Italy, Spain, the United Kingdom, Germany, Canada, Brazil, Australia, the Netherlands and 15 more. Country and city lists for energy efficiency contractors are linked below.
What qualifies
Companies worldwide whose own description of what they do matches “energy efficiency contractors”. Matching reads each company's description, not its industry code or its name.
RevenueBase Smart Search
RevenueBase Smart Search is how this list is assembled and how each row is rated. RevenueBase's data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to a category defined in a user's own words. Each row is rated strong evidence (its own description names energy efficiency contractors), partial evidence (it names part of the category) or indirect evidence (the description shown names none of it and the match rests on the rest of the company's profile). The description supporting each rating is quoted on the row.
What we exclude
Companies whose own description does not clearly place them among energy efficiency contractors, and records with no verified work email.
Match quality
In blind human judging of this matching method, 86% of matched companies were on target. Expect roughly 1 in 7 rows to be adjacent to the category rather than a pure play. Every row shows the company's own description and its RevenueBase Smart Search rating so you can judge each match yourself. Read the full methodology: how the lists are built, how the judging worked, and what the figure means.
Ranking
Team size, largest first: companies are ordered by the number of professionals RevenueBase tracks at each one. Employee ranges shown are reported bands, for context.
Verification
Every listed company carries at least one verified work email, 30,358 across the full list. Contacts re-verify on a rolling cadence, and each contact's own verification date is shown inside RevenueBase.
Refresh
This page's figures were pulled from the company graph on September 16, 2026. Lists refresh periodically as the graph is re-checked.
Corrections
Wrong category, wrong headquarters, or a company that has closed? Use “Report an issue” on any row. Reports go to the RevenueBase Data Team and feed back into the company graph.

Energy efficiency contractors by location

31 lists · largest first

Every Energy efficiency contractors list RevenueBase publishes, by country and city. Counts are matching companies in each list as of its own refresh date.

Countries

Cities

Frequently asked

What is RevenueBase Smart Search?

RevenueBase Smart Search is how RevenueBase decides which companies belong on this list and how strongly each one fits. Its data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to the category the list is about. Each row is rated strong evidence when the company's own description names energy efficiency contractors, partial evidence when it names part of the category, and indirect evidence when the description shown names none of it and the match rests on the rest of the company's profile.

How many energy efficiency contractors are there worldwide?

RevenueBase identified 7,333 energy efficiency contractors worldwide as of September 2026, matched on each company's own description of what it does rather than its industry code.

What is the largest company on this list?

British GAS, headquartered in Windsor, tops this list with the largest team on record.

Which country has the most energy efficiency contractors?

The United States leads with 2,028 companies, followed by France (921) and Italy (604). Every energy efficiency contractors list by country and city is linked on this page.

Which city has the most energy efficiency contractors?

Paris leads with 123 headquartered companies, followed by Madrid (114) and New York (75).

How do I get contact information for these companies?

A free RevenueBase account lets you run this exact search and work the top results, verified emails and direct dials included. Upgrading unlocks all 30,358 verified decision-maker contacts tracked across these 7,333 companies.

How current is this list?

The list refreshes periodically as the company graph is re-checked. This page's figures were pulled on September 16, 2026.

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About this data

RevenueBase is a B2B data infrastructure company. Its company graph covers 60 million companies and 398.9 million professional contacts, with emails verified on a rolling cadence rather than scraped once and left to decay. These company lists are generated directly from that graph with RevenueBase Smart Search, the same natural-language company search every RevenueBase user has: describe a market in plain words, get the companies that match, and add verified emails and direct dials for the people at them. It is the same data that powers RevenueBase's B2B data products, and a free account includes 500 credits to start. How these lists are built and judged.