Company lists · Data verified August 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 Verified Aug 28, 2026 2,339 companies tracked

There are 2,339 energy efficiency consulting firms headquartered in the United States (RevenueBase, August 2026). RevenueBase 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. Data current as of August 28, 2026.

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 verified Aug 28, 2026. Click a count to unlock that company's people.
#	Company	HQ	Employees	Contacts	Verified emails
1	Ameresco	Framingham, MA	1,001-5,000	1,475	1,125
2	Willdan	Anaheim, CA	1,001-5,000	838	636
3	Syska Hennessy Group	Jacksonville, FL	501-1,000	806	416
4	Resource Innovations	Chandler, AZ	501-1,000	724	558
5	Albireo Energy	New York	1,001-5,000	685	382
6	Noresco	Westminster, CO	201-500	484	249
7	Sitelogiq	Minneapolis, MN	501-1,000	451	283
8	TRIO	Mclean, VA	201-500	382	245
9	P2s	Irvine, CA	201-500	370	208
10	Wendel Companies	Middletown, CT	201-500	354	238
11	Cascade Energy	Burlington, VT	201-500	290	194
12	CMC Energy Services	Yalesville, CT	201-500	254	155
13	Lime Energy	Newark, NJ	201-500	233	53
14	Mantis Innovation	Waco, TX	201-500	231	183
15	Dalkia Energy Solutions	Beverly, MA	201-500	212	67
16	PEG	Fairfax, VA	201-500	211	68
17	Energy Management Collaborative EMC	Minneapolis, MN	201-500	197	132
18	Cenergistic	Dallas, TX	201-500	187	140
19	Mcclure Company	Wilkes-Barre, PA	201-500	170	89
20	Energy Network	Elkhorn, NE	201-500	157	25
21	RISE	Cranston, RI	201-500	151	57
22	Four Seasons Environmental, INC	Monroe, OH	201-500	134	7
23	Synergy Companies	Fresno, CA	501-1,000	124	31
24	Envocore	Gambrills, MD	201-500	115	80
25	Adm, A Qualus Company	Reno, NV	1,001-5,000	102	47

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 Aug 28, 2026

1-10Median size (employees)

New YorkLargest hub · 91 HQs

14,156Contacts with mobile numbers

0Emails re-verified in last 30 days

Companies by employee count

1-10

1,359

11-50

732

51-200

180

201-500

501-1,000

1,001-5,000

10001+

Energy efficiency consulting firms by metro

Metro	Companies
Energy efficiency consulting firms in New York	91
Energy efficiency consulting firms in Houston	69
Energy efficiency consulting firms in Chicago	38
Energy efficiency consulting firms in Atlanta	37
Energy efficiency consulting firms in Austin	37
Energy efficiency consulting firms in Denver	36
Energy efficiency consulting firms in Dallas	33
Energy efficiency consulting firms in Portland	30

How this list was built

Source: The RevenueBase company graph: 21.3 million companies and 398.9 million professional contacts resolved from primary sources.
Inclusion: Companies whose own business descriptions match “energy efficiency consulting firms”, with match quality audited by blind human judging, and headquartered in the United States.
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: Contact records re-verify on a rolling cadence; 0 contacts on this list were re-verified in the last 30 days.
Refresh: Lists are refreshed periodically as the underlying company graph is re-verified. Last verified Aug 28, 2026.

Frequently asked

How many energy efficiency consulting firms are there based in the United States?

There are 2,339 energy efficiency consulting firms headquartered in the United States as of August 2026 (RevenueBase).

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 is refreshed periodically as the underlying company graph is re-verified. It was last verified on August 28, 2026.

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About this data

RevenueBase is a B2B contact data platform. Its company graph covers 21.3 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, the same data that powers RevenueBase's B2B data products and the free research portal.