Company lists · Data refreshed September 2026

Top 25 Energy efficiency consulting firms worldwide

RevenueBase identified 11,412 energy efficiency consulting firms worldwide as of September 2026 and tracks 126,755 professional contacts across them, including 43,986 with verified work emails and 18,783 with mobile numbers. The United States is the largest market and Madrid the largest hub.

This list covers energy efficiency consulting firms 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 2, 2026. Country and city lists for energy efficiency consulting firms 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 RevenueBase Smart Search rating on every row Refreshed Sep 2, 2026 86% judged on-target in blind review
11,412Companies
126,755Contacts tracked
43,986Verified emails
18,783Mobile numbers
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The 25 largest energy efficiency consulting firms worldwide

Ranked by team size
Top 25 of 11,412 energy efficiency consulting firms worldwide, ranked by team size, largest first. Data refreshed Sep 2, 2026. RevenueBase Smart Search rates how each company's information relates to energy efficiency consulting firms: 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 evidenceStaines, GB10001+9,287 contacts →

Indirect evidence

“Taking care of things.”

Source: RevenueBase Database · checked Sep 2, 2026
2Indirect evidenceSaint-Andre-Lez-Lille, FR10001+8,459 contacts →

Indirect evidence

“Dalkia : ensemble, relevons le défi climatique!”

Source: RevenueBase Database · checked Sep 2, 2026
3Partial evidenceDubai, United Arab EmiratesHQ checked Sep 2, 20265,001-10,0004,058 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 2, 2026
4Strong evidenceToronto, ON, CA1,001-5,0002,137 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 2, 2026
5Partial evidenceFramingham, MA, US1,001-5,0001,475 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 2, 2026
6Indirect evidenceOslo, NO1,001-5,0001,149 contacts →

Indirect evidence

“GK er en ledende teknisk entreprenør og servicepartner.”

Source: RevenueBase Database · checked Sep 2, 2026
7Partial evidenceAnaheim, CA, US1,001-5,000838 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 2, 2026
8Indirect evidenceJacksonville, FL, US501-1,000806 contacts →

Indirect evidence

“Consult Engineer Commission At Syska Hennessy Group, we create exceptional environments.”

Source: RevenueBase Database · checked Sep 2, 2026
9Partial evidenceChandler, AZ, US501-1,000724 contacts →

Partial evidence

“Resource Innovations (RI) is an energy transformation firm.”

Source: RevenueBase Database · checked Sep 2, 2026
10Partial evidenceNew York, US1,001-5,000685 contacts →

Partial evidence

“Albireo Energy is a leading independent building controls and energy services provider recognized by customers for creating intelligent, high-performance buildings.”

Source: RevenueBase Database · checked Sep 2, 2026
11Partial evidenceWestminster, CO, US201-500484 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 2, 2026
12Partial evidenceAubervilliers, FR1,001-5,000469 contacts →

Partial evidence

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

Source: RevenueBase Database · checked Sep 2, 2026
13Indirect evidenceMinneapolis, MN, US501-1,000451 contacts →

Indirect evidence

“SitelogIQ provides design, engineering, and construction management services that help organizations nationwide modernize their facilities and infrastructure.”

Source: RevenueBase Database · checked Sep 2, 2026
14Partial evidenceParis, FR501-1,000400 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 2, 2026
15Partial evidenceMclean, VA, US201-500382 contacts →

Partial evidence

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

Source: RevenueBase Database · checked Sep 2, 2026
16Indirect evidenceIrvine, CA, US201-500370 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 2, 2026
17Strong evidenceHalifax, NS, CA201-500355 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 2, 2026
18Strong evidenceMiddletown, CT, US201-500354 contacts →

Strong evidence

“Wendel is an Architecture, Engineering, Energy Efficiency, and Construction Management Firm that delivers customized solutions and turnkey projects in innovative ways.”

Source: RevenueBase Database · checked Sep 2, 2026
19Partial evidenceRiyadh, Saudi ArabiaHQ checked Sep 2, 2026201-500342 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 2, 2026
20Indirect evidenceSandton, ZA201-500334 contacts →

Indirect evidence

“National Utility Service, Inc.”

Source: RevenueBase Database · checked Sep 2, 2026
21Indirect evidenceLondon, GB51-200321 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 2, 2026
22Partial evidenceRedditch, GB51-200315 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 2, 2026
23Indirect evidenceCreteil, FR501-1,000311 contacts →

Indirect evidence

“Depuis 40 ans, MANERGY s’affirme comme une société indépendante de référence, spécialisée dans l’ingénierie et le conseil en transition énergétique et environnementale.”

Source: RevenueBase Database · checked Sep 2, 2026
24Partial evidenceParis, FR201-500298 contacts →

Partial evidence

“Effy, spécialiste de l’efficience énergétique.”

Source: RevenueBase Database · checked Sep 2, 2026
25Indirect evidenceClichy, FR201-500292 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 2, 2026

Showing 25 of 11,412 energy efficiency consulting firms worldwide

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Energy efficiency consulting firms worldwide at a glance

As of Sep 2, 2026
34.7%Verified-email coverage
14.8%Mobile-number coverage
11.1Average contacts per company
1-10Median size (employees)
1.5%Largest-city concentration · Madrid
Sep 2, 2026Page data refreshed

Companies by employee count

1-10
7,314
11-50
3,136
51-200
645
201-500
118
501-1,000
30
1,001-5,000
24
5,001-10,000
2
10001+
3

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 firms, 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
35 countries, largest first: the United States, France, Spain, Germany, the United Kingdom, Italy, Brazil, the Netherlands, Canada, Australia and 25 more. Country and city lists for energy efficiency consulting firms are linked below.
What qualifies
Companies worldwide whose own description of what they do matches “energy efficiency consulting firms”. 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 firms), 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 firms, 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, 43,986 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 between September 2, 2026 and September 14, 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 firms by location

64 lists · largest first

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

RevenueBase identified 11,412 energy efficiency consulting firms 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 Staines, tops this list with the largest team on record.

Which country has the most energy efficiency consulting firms?

The United States leads with 2,339 companies, followed by France (1,218) and Spain (924). Every energy efficiency consulting firms list by country and city is linked on this page.

Which city has the most energy efficiency consulting firms?

Madrid leads with 172 headquartered companies, followed by Paris (171) and London (135).

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 43,986 verified decision-maker contacts tracked across these 11,412 companies.

How current is this list?

The list refreshes periodically as the company graph is re-checked. This page's figures were pulled from the company graph between September 2, 2026 and September 14, 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.