Company lists · Data refreshed September 2026

Top 25 Energy efficiency consulting companies worldwide

Name: Energy efficiency consulting companies worldwide
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Sep 21, 2026 13,441 companies tracked

RevenueBase identified 13,441 energy efficiency consulting companies worldwide as of September 2026 and tracks 133,393 professional contacts across them, including 41,585 with verified work emails. The United States is the largest market and Madrid the largest hub.

This list covers energy efficiency consulting companies 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 21, 2026. Country and city lists for energy efficiency consulting companies 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 21, 2026 86% judged on-target in blind review

13,441Companies

133,393Contacts tracked

41,585Verified emails

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The 25 largest energy efficiency consulting companies worldwide

Ranked by team size

Top 25 of 13,441 energy efficiency consulting companies worldwide, ranked by team size, largest first. Data refreshed Sep 21, 2026. RevenueBase Smart Search rates how each company's information relates to energy efficiency consulting companies: 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.
#	Company	RevenueBase Smart Search	Headquarters	Employees	Contacts
1	British GAS	Indirect evidence	Windsor, United KingdomHQ checked Sep 21, 2026	10001+	9,238 contacts →
	Indirect evidence “Taking care of things.” Source: RevenueBase Database · checked Sep 21, 2026
2	Dalkia	Indirect evidence	Saint-andré-lez-lille, FranceHQ checked Sep 21, 2026	10001+	8,427 contacts →
	Indirect evidence “Dalkia : ensemble, relevons le défi climatique!” Source: RevenueBase Database · checked Sep 21, 2026
3	Enova By Veolia	Partial evidence	Dubai, United Arab EmiratesHQ checked Sep 21, 2026	5,001-10,000	4,058 contacts →
	Partial evidence “Enova is the regional leader in integrated energy and multi-technical services, delivering comprehensive services to its clients.” Source: RevenueBase Database · checked Sep 21, 2026
4	Clearesult	Strong evidence	Austin, TX, United StatesHQ checked Sep 21, 2026	1,001-5,000	2,121 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 21, 2026
5	Ameresco	Partial evidence	Framingham, MA, United StatesHQ checked Sep 21, 2026	1,001-5,000	1,383 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 21, 2026
6	GK	Indirect evidence	Oslo, NorwayHQ checked Sep 21, 2026	1,001-5,000	1,150 contacts →
	Indirect evidence “GK er en ledende teknisk entreprenør og servicepartner.” Source: RevenueBase Database · checked Sep 21, 2026
7	Willdan	Partial evidence	Anaheim, CA, United StatesHQ checked Sep 21, 2026	1,001-5,000	851 contacts →
	Partial 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 21, 2026
8	3e Engenharia EM Eficiencia Energetica	Indirect evidence	BrazilHQ checked Sep 21, 2026	201-500	473 contacts →
	Indirect evidence “A 3E Engenharia atua nacionalmente, oferecendo soluções para empresas concessionárias de serviços públicos, no planejamento, gestão, execução e inovação em projetos de Eficiência…” Source: RevenueBase Database · checked Sep 21, 2026
9	Korra Energi	Strong evidence	Cairo, EgyptHQ checked Sep 21, 2026	1,001-5,000	469 contacts →
	Strong evidence “Korra Energi is a proud Egyptian leader in energy efficiency and construction services, backed by over 25 years of expertise and a vision of "Growth and Prosperity"(إعمار الأرض).” Source: RevenueBase Database · checked Sep 21, 2026
10	Veolia Industries Global Solutions	Partial evidence	Aubervilliers, FranceHQ checked Sep 21, 2026	1,001-5,000	460 contacts →
	Partial evidence “Veolia Industries Global Solutions est devenu Veolia Energie Performance depuis le 1er juin 2025.” Source: RevenueBase Database · checked Sep 21, 2026
11	Greenflex	Partial evidence	Paris, FranceHQ checked Sep 21, 2026	501-1,000	390 contacts →
	Partial evidence “Since 2009, GreenFlex has been a key partner in the energy, environmental and societal transformation of organizations, enabling them to change their trajectory towards an economy…” Source: RevenueBase Database · checked Sep 21, 2026
12	TRIO	Partial evidence	Irvine, CA, United StatesHQ checked Sep 21, 2026	201-500	383 contacts →
	Partial evidence “We are Trio – built from Edison Energy, Alfa Energy, and Altenex Energy.” Source: RevenueBase Database · checked Sep 21, 2026
13	P2s	Indirect evidence	Long Beach, CA, United StatesHQ checked Sep 21, 2026	201-500	375 contacts →
	Indirect evidence “P2S has brought forward-thinking, sustainable engineering solutions to California, the Pacific Northwest, and beyond, for over 30 years.” Source: RevenueBase Database · checked Sep 21, 2026
14	MCW Group Of Companies	Strong evidence	Toronto, ON, CanadaHQ checked Sep 21, 2026	201-500	363 contacts →
	Strong evidence “Since 1964 the MCW Group has built a solid reputation for the delivery of Professional Consulting Engineering Services, Energy Management Services, and Engineering Development…” Source: RevenueBase Database · checked Sep 21, 2026
15	AESA	Partial evidence	Barcelona, SpainHQ checked Sep 21, 2026	n/a	351 contacts →
	Partial evidence “Ingeniería y Consultoría Energética orientada a la búsqueda y el desarrollo de soluciones energéticas de alta eficiencia para sus Clientes.” Source: RevenueBase Database · checked Sep 21, 2026
16	ترشيد Tarshid	Partial evidence	Riyadh, Saudi ArabiaHQ checked Sep 21, 2026	201-500	342 contacts →
	Partial evidence “The National Energy Services Company (TARSHID) is a national company wholly owned by the Public Investment Fund (PIF).” Source: RevenueBase Database · checked Sep 21, 2026
17	NUS Consulting Group	Indirect evidence	Park Ridge, NJ, United StatesHQ checked Sep 21, 2026	201-500	336 contacts →
	Indirect evidence “National Utility Service, Inc.” Source: RevenueBase Database · checked Sep 21, 2026
18	Atelier TEN	Indirect evidence	London, United KingdomHQ checked Sep 21, 2026	51-200	323 contacts →
	Indirect evidence “As environmental design consultants, building services engineers and lighting designers, we are committed to high performance and sustainable design within the built environment.” Source: RevenueBase Database · checked Sep 21, 2026
19	ETP CC	Strong evidence	AustraliaHQ checked Sep 21, 2026	n/a	320 contacts →
	Strong evidence “Management Consulting in the Energy Sector” Source: RevenueBase Database · checked Sep 21, 2026
20	EIC Partnership	Partial evidence	Redditch, United KingdomHQ checked Sep 21, 2026	51-200	316 contacts →
	Partial evidence “EIC Partnership: A Legacy of Expertise, A Commitment to Sustainability With origins dating back to 1975, EIC has cultivated nearly 50 years of distinguished service in energy and…” Source: RevenueBase Database · checked Sep 21, 2026
21	Hellio	Indirect evidence	Clichy, FranceHQ checked Sep 21, 2026	201-500	293 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 21, 2026
22	EFFY	Partial evidence	Paris, FranceHQ checked Sep 21, 2026	201-500	292 contacts →
	Partial evidence “Effy, spécialiste de l’efficience énergétique.” Source: RevenueBase Database · checked Sep 21, 2026
23	Entes Elektronik	Strong evidence	Istanbul, TürkiyeHQ checked Sep 21, 2026	201-500	289 contacts →
	Strong evidence “A World Brand/Pride of Turkey In Energy Quality ENTES is a family that works ardently for energy quality and efficiency in our country, where energy is valuable and overcosting.” Source: RevenueBase Database · checked Sep 21, 2026
24	Cascade Energy	Partial evidence	Portland, OR, United StatesHQ checked Sep 21, 2026	201-500	288 contacts →
	Partial evidence “At Cascade Energy, we believe in better.” Source: RevenueBase Database · checked Sep 21, 2026
25	Lake Superior Consulting	Partial evidence	Duluth, MN, United StatesHQ checked Sep 21, 2026	201-500	281 contacts →
	Partial evidence “We act as an extension of your team, combining deep energy expertise with seamless alignment to your processes to advance projects with confidence.” Source: RevenueBase Database · checked Sep 21, 2026

RevenueBase Smart Search

RevenueBase Smart Search assesses information from a company’s LinkedIn profile, information supplied directly by the company, its website, and other publicly available sources. It uses that information to rate how closely the company relates to this list’s category: energy efficiency consulting companies. Every row carries its rating and the description the rating was read from, so each one can be checked rather than taken on trust.

Strong evidence: The company's own public description of its business names energy efficiency consulting companies.
Partial evidence: Its own public description names part of energy efficiency consulting companies, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name energy efficiency consulting companies. The match rests on the rest of the company's public profile rather than the one sentence quoted here, so this is the rating to check first.

RevenueBase Smart Search is how these lists are built: RevenueBase's data engine and AI assemble the companies that match a category defined in a user's own words, so a list can be about what companies actually do rather than about whichever industry code they were filed under.

Showing 25 of 13,441 energy efficiency consulting companies worldwide

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Energy efficiency consulting companies worldwide at a glance

As of Sep 21, 2026

31.2%Verified-email coverage

9.9Average contacts per company

1-10Median size (employees)

1.3%Largest-city concentration · Madrid

Sep 21, 2026Page data refreshed

Companies by employee count

1-10

8,755

11-50

3,625

51-200

768

201-500

135

501-1,000

1,001-5,000

5,001-10,000

10001+

Email recency is reported on each country list linked below.

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 consulting companies, 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: Every country. Country and city lists for energy efficiency consulting companies are linked below.
What qualifies: Companies worldwide whose own description of what they do matches “energy efficiency consulting companies”. 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 consulting companies), 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 consulting companies, 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, 41,585 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 21, 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 consulting companies by location

48 lists · largest first

Every Energy efficiency consulting companies 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 consulting companies, 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 consulting companies are there worldwide?

RevenueBase identified 13,441 energy efficiency consulting companies 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 consulting companies?

The United States leads with 1,922 companies, followed by France (1,182) and Spain (953). Every energy efficiency consulting companies list by country and city is linked on this page.

Which city has the most energy efficiency consulting companies?

Madrid leads with 171 headquartered companies, followed by Paris (161) and London (118).

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 41,585 verified decision-maker contacts tracked across these 13,441 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 21, 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.