Company lists · Data refreshed September 2026

Top 25 Building energy efficiency retrofit companies based in the United States

Name: Building energy efficiency retrofit companies based in the United States
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Sep 16, 2026 1,393 companies tracked

RevenueBase identified 1,393 building energy efficiency retrofit companies headquartered in the United States as of September 2026 and tracks 15,350 professional contacts across them, including 5,842 with verified work emails. New York is the largest hub.

This list covers building energy efficiency retrofit companies 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 16, 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 HQ checked on every row RevenueBase Smart Search rating on every row Refreshed Sep 16, 2026 86% judged on-target in blind review

1,393Companies

15,350Contacts tracked

5,842Verified emails

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The 25 largest building energy efficiency retrofit companies based in the United States

Ranked by team size

Top 25 of 1,393 building energy efficiency retrofit companies based in the United States, ranked by team size, largest first. Data refreshed Sep 16, 2026. RevenueBase Smart Search rates how each company's information relates to building energy efficiency retrofit 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	Ameresco	Partial evidence	Framingham, MA, United StatesHQ checked Sep 16, 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 16, 2026
2	Noresco	Strong evidence	Westborough, MA, United StatesHQ checked Sep 16, 2026	201-500	481 contacts →
	Strong 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
3	Homeworks Energy, INC	Strong evidence	Medford, MA, United StatesHQ checked Sep 16, 2026	201-500	356 contacts →
	Strong evidence “At HomeWorks Energy, our mission is simple, literally: Energy Efficiency, Simplified.” Source: RevenueBase Database · checked Sep 16, 2026
4	Lime Energy	Strong evidence	Newark, NJ, United StatesHQ checked Sep 16, 2026	201-500	233 contacts →
	Strong evidence “Lime Energy is building a new energy future.” Source: RevenueBase Database · checked Sep 16, 2026
5	Dalkia Energy Solutions	Strong evidence	Beverly, MA, United StatesHQ checked Sep 16, 2026	201-500	210 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 16, 2026
6	Bright Power	Strong evidence	New York, NY, United StatesHQ checked Sep 16, 2026	51-200	205 contacts →
	Strong evidence “Bright Power is a leading provider of energy efficiency and decarbonization solutions for the real estate industry.” Source: RevenueBase Database · checked Sep 16, 2026
7	Energy Management Collaborative EMC	Strong evidence	Minneapolis, MN, United StatesHQ checked Sep 16, 2026	201-500	193 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 16, 2026
8	Hill York	Strong evidence	Dania Beach, FL, United StatesHQ checked Sep 16, 2026	201-500	168 contacts →
	Strong evidence “Hill York is a full service contractor that offers a full array of energy efficient air-conditioning services from concept to completion, maintenance to repair and everything in…” Source: RevenueBase Database · checked Sep 16, 2026
9	Mcclure Company	Partial evidence	Harrisburg, PA, United StatesHQ checked Sep 16, 2026	201-500	166 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 16, 2026
10	GSM Services	Indirect evidence	Gastonia, NC, United StatesHQ checked Sep 16, 2026	201-500	159 contacts →
	Indirect evidence “For nearly a century, GSM Services has built its reputation on reliability, honesty, expert service, and high-quality workmanship.” Source: RevenueBase Database · checked Sep 16, 2026
11	RISE	Strong evidence	Cranston, RI, United StatesHQ checked Sep 16, 2026	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 16, 2026
12	Willdan Performance Engineering	Partial evidence	Denver, KS, United StatesHQ checked Sep 16, 2026	51-200	129 contacts →
	Partial evidence “Willdan Performance Engineering specializes in energy and infrastructure improvement projects through design-build and performance contracting.” Source: RevenueBase Database · checked Sep 16, 2026
13	Cypress Envirosystems	Partial evidence	San Jose, CA, United StatesHQ checked Sep 16, 2026	11-50	128 contacts →
	Partial evidence “We Make Buildings Brilliant.” Source: RevenueBase Database · checked Sep 16, 2026
14	Synergy Companies	Strong evidence	Fresno, CA, United StatesHQ checked Sep 16, 2026	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 16, 2026
15	Erus Energy	Strong evidence	Phoenix, AZ, United StatesHQ checked Sep 16, 2026	51-200	118 contacts →
	Strong evidence “Erus Energy helps building owners evaluate and finance investments in Solar Energy and other energy saving equipment.” Source: RevenueBase Database · checked Sep 16, 2026
16	Melink Corporation	Strong evidence	Milford, OH, United StatesHQ checked Sep 16, 2026	51-200	116 contacts →
	Strong evidence “We are a global provider of energy efficiency solutions for commercial buildings with five business offerings: HVAC Testing, Adjusting & Balancing, Intelli-Hood® Kitchen…” Source: RevenueBase Database · checked Sep 16, 2026
17	PSD	Strong evidence	Ithaca, NY, United StatesHQ checked Sep 16, 2026	51-200	112 contacts →
	Strong evidence “PSD is an energy efficiency services and technology company.” Source: RevenueBase Database · checked Sep 16, 2026
18	Midwest Mechanical Commercial, Industrial Hvac Mechanical Services	Strong evidence	Lombard, IL, United StatesHQ checked Sep 16, 2026	51-200	110 contacts →
	Strong evidence “Chicago's Facilities Management Company Midwest Mechanical is a commercial HVAC services and facility management company focused on energy efficiency for building owners and…” Source: RevenueBase Database · checked Sep 16, 2026
19	Blocpower	Partial evidence	Brooklyn, United StatesHQ checked Sep 16, 2026	51-200	110 contacts →
	Partial evidence “BlocPower is upgrading America’s buildings to be smarter, greener and healthier for all-fighting the climate crisis and creating good green jobs.” Source: RevenueBase Database · checked Sep 16, 2026
20	Brightcore Energy	Partial evidence	Armonk, NY, United StatesHQ checked Sep 16, 2026	51-200	108 contacts →
	Partial evidence “Brightcore Energy is a leading renewable energy solutions provider serving commercial, institutional, and government clients.” Source: RevenueBase Database · checked Sep 16, 2026
21	Apadana	Partial evidence	New Hope, MN, United StatesHQ checked Sep 16, 2026	51-200	107 contacts →
	Partial evidence “Apadana was founded in 2013 by electrical and mechanical engineers who committed their expertise to delivering energy conservation and renewable energy generation solutions with a…” Source: RevenueBase Database · checked Sep 16, 2026
22	Earthlight Technologies	Strong evidence	Ellington, CT, United StatesHQ checked Sep 16, 2026	51-200	99 contacts →
	Strong evidence “Earthlight is a Solar and Energy Efficiency contractor dedicated to meeting people’s ecofriendly needs by providing them with quality energy conservation solutions.” Source: RevenueBase Database · checked Sep 16, 2026
23	KW Engineering	Strong evidence	Oakland, CA, United StatesHQ checked Sep 16, 2026	51-200	97 contacts →
	Strong evidence “In 1998, I started kW Engineering as a two-person firm with a singular vision: to become the leading technical experts at saving money in buildings by saving energy and water.” Source: RevenueBase Database · checked Sep 16, 2026
24	Optimum Energy	Strong evidence	Seattle, WA, United StatesHQ checked Sep 16, 2026	51-200	86 contacts →
	Strong evidence “With 20 years of experience and 300+ plants and institutions served globally, nobody understands energy infrastructure, efficiency, and financial opportunity quite like Optimum…” Source: RevenueBase Database · checked Sep 16, 2026
25	Dreamline AI	Partial evidence	Orlando, FL, United StatesHQ checked Sep 16, 2026	51-200	78 contacts →
	Partial evidence “Dreamline AI closes the funding gap for the clean energy economy.” Source: RevenueBase Database · checked Sep 16, 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: building energy efficiency retrofit 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 building energy efficiency retrofit companies.
Partial evidence: Its own public description names part of building energy efficiency retrofit companies, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name building energy efficiency retrofit 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 1,393 building energy efficiency retrofit companies based in the United States

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Building energy efficiency retrofit companies based in the United States at a glance

As of Sep 16, 2026

38.1%Verified-email coverage

11.0Average contacts per company

11-50Median size (employees)

2.4%Largest-city concentration · New York

Sep 16, 2026Page data refreshed

Companies by employee count

1-10

684

11-50

537

51-200

136

201-500

501-1,000

1,001-5,000

Email recency for this list is measured worldwide rather than for United States, so it is reported there. Company counts and contact totals on this page are exact for United States, over 1,393 companies.

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 building energy efficiency retrofit 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.
What qualifies: Companies headquartered in the United States whose own description of what they do matches “building energy efficiency retrofit 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 building energy efficiency retrofit 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 building energy efficiency retrofit companies, 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, 5,842 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.

Building energy efficiency retrofit companies by metro

Building energy efficiency retrofit companies in New York34

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 building energy efficiency retrofit 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 building energy efficiency retrofit companies are there based in the United States?

RevenueBase identified 1,393 building energy efficiency retrofit companies 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 building energy efficiency retrofit companies?

New York leads with 34 headquartered companies, followed by Denver (21) and Houston (21).

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 5,842 verified decision-maker contacts tracked across these 1,393 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.