Company lists · Data refreshed September 2026

Top 25 Energy efficiency consulting firms based in the United States

Name: Energy efficiency consulting firms based in the United States
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Sep 2, 2026 2,339 companies tracked

RevenueBase identified 2,339 energy efficiency consulting firms headquartered in the United States as of September 2026 and tracks 32,555 professional contacts across them, including 14,308 with verified work emails and 14,156 with mobile numbers. New York is the largest hub.

This list covers energy efficiency consulting firms headquartered in the United States, 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.

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

2,339Companies

32,555Contacts tracked

14,308Verified emails

14,156Mobile numbers

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The 25 largest energy efficiency consulting firms based in the United States

Ranked by team size

Top 25 of 2,339 energy efficiency consulting firms based in the United States, 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.
#	Company	RevenueBase Smart Search	Headquarters	Employees	Contacts
1	Ameresco	Partial evidence	Framingham, MA, United States	1,001-5,000	1,475 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
2	Willdan	Partial evidence	Anaheim, CA, United States	1,001-5,000	838 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
3	Syska Hennessy Group	Indirect evidence	Jacksonville, FL, United States	501-1,000	806 contacts →
	Indirect evidence “Consult Engineer Commission At Syska Hennessy Group, we create exceptional environments.” Source: RevenueBase Database · checked Sep 2, 2026
4	Resource Innovations	Partial evidence	Chandler, AZ, United States	501-1,000	724 contacts →
	Partial evidence “Resource Innovations (RI) is an energy transformation firm.” Source: RevenueBase Database · checked Sep 2, 2026
5	Albireo Energy	Partial evidence	New York, United States	1,001-5,000	685 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
6	Noresco	Partial evidence	Westminster, CO, United States	201-500	484 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
7	Sitelogiq	Indirect evidence	Minneapolis, MN, United States	501-1,000	451 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
8	TRIO	Partial evidence	Mclean, VA, United States	201-500	382 contacts →
	Partial evidence “We are Trio – built from Edison Energy, Alfa Energy, and Altenex Energy.” Source: RevenueBase Database · checked Sep 2, 2026
9	P2s	Indirect evidence	Irvine, CA, United States	201-500	370 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
10	Wendel Companies	Strong evidence	Middletown, CT, United States	201-500	354 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
11	Cascade Energy	Partial evidence	Burlington, VT, United States	201-500	290 contacts →
	Partial evidence “At Cascade Energy, we believe in better.” Source: RevenueBase Database · checked Sep 2, 2026
12	CMC Energy Services	Strong evidence	Yalesville, CT, United States	201-500	254 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 2, 2026
13	Lime Energy	Partial evidence	Newark, NJ, United States	201-500	233 contacts →
	Partial evidence “Lime Energy is building a new energy future.” Source: RevenueBase Database · checked Sep 2, 2026
14	Mantis Innovation	Partial evidence	Waco, TX, United States	201-500	231 contacts →
	Partial evidence “At Mantis Innovation, our experts provide data-driven, consultative services designed to optimize your facility, sustainability, and energy management strategies, while ultimately…” Source: RevenueBase Database · checked Sep 2, 2026
15	Dalkia Energy Solutions	Strong evidence	Beverly, MA, United States	201-500	212 contacts →
	Strong evidence “Dalkia Energy Solutions, a subsidiary of the EDF (Électricité de France) Group, is a national leader in energy efficiency and sustainability for commercial, industrial, and…” Source: RevenueBase Database · checked Sep 2, 2026
16	PEG	Partial evidence	Fairfax, VA, United States	201-500	211 contacts →
	Partial evidence “PEG presents a comprehensive capacity for the evaluation and understanding of a broad base of energy and environmental sustainability related programs, policies and initiatives.” Source: RevenueBase Database · checked Sep 2, 2026
17	Energy Management Collaborative EMC	Strong evidence	Minneapolis, MN, United States	201-500	197 contacts →
	Strong evidence “EMC manages and scales turnkey energy efficiency solutions for Fortune 500 clients across their North American portfolios.” Source: RevenueBase Database · checked Sep 2, 2026
18	Cenergistic	Partial evidence	Dallas, TX, United States	201-500	187 contacts →
	Partial evidence “At Cenergistic, energy conservation starts with people.” Source: RevenueBase Database · checked Sep 2, 2026
19	Mcclure Company	Partial evidence	Wilkes-Barre, PA, United States	201-500	170 contacts →
	Partial evidence “Headquartered in Harrisburg, Pennsylvania, McClure Company is one of the mid-Atlantic's largest, fully integrated mechanical construction, engineering, maintenance and energy…” Source: RevenueBase Database · checked Sep 2, 2026
20	Energy Network	Partial evidence	Elkhorn, NE, United States	201-500	157 contacts →
	Partial evidence “Energy Network has four areas of expertise, each of which is focused on reducing operational expenses and at the same time augment our clients’ sustainability objectives.” Source: RevenueBase Database · checked Sep 2, 2026
21	RISE	Strong evidence	Cranston, RI, United States	201-500	151 contacts →
	Strong evidence “RISE is a pioneer in the delivery of turnkey energy-efficiency services for residential, commercial and industrial facilities.” Source: RevenueBase Database · checked Sep 2, 2026
22	Four Seasons Environmental, INC	Indirect evidence	Monroe, OH, United States	201-500	134 contacts →
	Indirect evidence Source: RevenueBase Database · checked Sep 2, 2026
23	Synergy Companies	Strong evidence	Fresno, CA, United States	501-1,000	124 contacts →
	Strong evidence “Synergy Companies is the largest energy services companies in California and provides a comprehensive approach to energy efficiency and environmental solutions in both the…” Source: RevenueBase Database · checked Sep 2, 2026
24	Envocore	Indirect evidence	Gambrills, MD, United States	201-500	115 contacts →
	Indirect evidence “We make sustainable happen.” Source: RevenueBase Database · checked Sep 2, 2026
25	Adm, A Qualus Company	Partial evidence	Reno, NV, United States	1,001-5,000	102 contacts →
	Partial evidence “Qualus is a leading pure-play power services firm and innovator at the forefront of the energy transition and transformation, with differentiated capabilities across grid…” Source: RevenueBase Database · checked Sep 2, 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 firms. 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 firms.
Partial evidence: Its own public description names part of energy efficiency consulting firms, 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 firms. 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 2,339 energy efficiency consulting firms based in the United States

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Energy efficiency consulting firms based in the United States at a glance

As of Sep 2, 2026

44.0%Verified-email coverage

43.5%Mobile-number coverage

13.9Average contacts per company

1-10Median size (employees)

3.9%Largest-city concentration · New York

Sep 2, 2026Page data refreshed

Companies by employee count

1-10

1,359

11-50

732

51-200

180

201-500

501-1,000

1,001-5,000

10001+

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.
What qualifies: Companies headquartered in the United States 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. Companies headquartered outside United States are excluded even when they keep an office there.
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, 14,308 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 2, 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 metro

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 based in the United States?

RevenueBase identified 2,339 energy efficiency consulting firms headquartered in the United States 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?

Ameresco, headquartered in Framingham, tops this list with the largest team on record.

Which city has the most energy efficiency consulting firms?

New York leads with 91 headquartered companies, followed by Houston (69) and Chicago (38).

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 14,308 verified decision-maker contacts tracked across these 2,339 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 2, 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.