Company lists · Data refreshed September 2026

Top 25 Retrofit contractors based in the United States

Name: Retrofit contractors based in the United States
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Sep 17, 2026 5,218 companies tracked

RevenueBase identified 5,218 retrofit contractors headquartered in the United States as of September 2026 and tracks 65,388 professional contacts across them, including 23,994 with verified work emails. New York is the largest hub.

This list covers retrofit contractors 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 17, 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 17, 2026 86% judged on-target in blind review

5,218Companies

65,388Contacts tracked

23,994Verified emails

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The 25 largest retrofit contractors based in the United States

Ranked by team size

Top 25 of 5,218 retrofit contractors based in the United States, ranked by team size, largest first. Data refreshed Sep 17, 2026. RevenueBase Smart Search rates how each company's information relates to retrofit contractors: 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	Mckinstry	Indirect evidence	Seattle, WA, United StatesHQ checked Sep 17, 2026	1,001-5,000	2,213 contacts →
	Indirect evidence “We're a national construction and energy services company dedicated to innovating the waste and climate harm out of the built environment.” Source: RevenueBase Database · checked Sep 17, 2026
2	Ameresco	Indirect evidence	Framingham, MA, United StatesHQ checked Sep 17, 2026	1,001-5,000	1,383 contacts →
	Indirect 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 17, 2026
3	Climatec, LLC	Indirect evidence	Phoenix, AZ, United StatesHQ checked Sep 17, 2026	1,001-5,000	863 contacts →
	Indirect evidence “Climatec has been making buildings safer, more comfortable and efficient for over 40 years.” Source: RevenueBase Database · checked Sep 17, 2026
4	SEL Construction Corporation	Partial evidence	Loomis, CA, United StatesHQ checked Sep 17, 2026	n/a	722 contacts →
	Partial evidence “Experienced commercial contractor specializing in renewable energy, electrical, and roofing projects for privately-owned buildings as well as state/local government buildings in…” Source: RevenueBase Database · checked Sep 17, 2026
5	Baker Group	Partial evidence	Ankeny, IA, United StatesHQ checked Sep 17, 2026	1,001-5,000	655 contacts →
	Partial evidence “Established in 1963, Baker Group is Iowa’s premier full-service specialty contractor-serving commercial, industrial, institutional, and mission-critical markets across the country.” Source: RevenueBase Database · checked Sep 17, 2026
6	Alterman, INC	Indirect evidence	Live Oak, TX, United StatesHQ checked Sep 17, 2026	501-1,000	597 contacts →
	Indirect evidence “Since 1923, Alterman has provided electrical construction on many of San Antonio and Austin's most impressive landmarks and contemporary structures.” Source: RevenueBase Database · checked Sep 17, 2026
7	Murphy Company	Partial evidence	St. Louis, MO, United StatesHQ checked Sep 17, 2026	1,001-5,000	579 contacts →
	Partial evidence “Per Colorado State Law Our CO Plumbing Contractor License Our Master Plumbing License is MP.03001288.” Source: RevenueBase Database · checked Sep 17, 2026
8	Pieper Electric, INC	Indirect evidence	New Berlin, WI, United StatesHQ checked Sep 17, 2026	501-1,000	498 contacts →
	Indirect evidence “At Pieper Electric, Inc,"Our People Are Our Power" isn't just a phrase; it's our way of life.” Source: RevenueBase Database · checked Sep 17, 2026
9	Noresco	Indirect evidence	Westborough, MA, United StatesHQ checked Sep 17, 2026	201-500	481 contacts →
	Indirect 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 17, 2026
10	Carlisle Companies Incorporated	Indirect evidence	Scottsdale, AZ, United StatesHQ checked Sep 17, 2026	5,001-10,000	472 contacts →
	Indirect evidence “Carlisle Companies Incorporated is a leading supplier of innovative building envelope products and solutions for more energy efficient buildings.” Source: RevenueBase Database · checked Sep 17, 2026
11	Sitelogiq	Indirect evidence	Minneapolis, MN, United StatesHQ checked Sep 17, 2026	501-1,000	450 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 17, 2026
12	Jmeg Electrical Contractors	Indirect evidence	Farmers Branch, TX, United StatesHQ checked Sep 17, 2026	501-1,000	437 contacts →
	Indirect evidence “JMEG is a team of professionals who have been providing electrical construction services for over 35 years throughout the state of Texas.” Source: RevenueBase Database · checked Sep 17, 2026
13	Romanoff Group	Indirect evidence	Gahanna, OH, United StatesHQ checked Sep 17, 2026	1,001-5,000	431 contacts →
	Indirect evidence “The Romanoff Group of Companies has been dedicated to providing specialized electrical, plumbing, and heating and cooling services since 1992.” Source: RevenueBase Database · checked Sep 17, 2026
14	John W. Danforth Company	Indirect evidence	Tonawanda, NY, United StatesHQ checked Sep 17, 2026	501-1,000	415 contacts →
	Indirect evidence “We are powered by the best people in the industry.” Source: RevenueBase Database · checked Sep 17, 2026
15	Strada Services	Indirect evidence	Sanford, FL, United StatesHQ checked Sep 17, 2026	1,001-5,000	391 contacts →
	Indirect evidence “Strada Services is a full service electrical, security, and air conditioning contracting company servicing residential, commercial, and industrial customers in Florida and in the…” Source: RevenueBase Database · checked Sep 17, 2026
16	Veregy	Indirect evidence	Phoenix, MO, United StatesHQ checked Sep 17, 2026	501-1,000	383 contacts →
	Indirect evidence “Veregy is an award-winning NAESCO-Accredited decarbonization company focusing on accelerating and simplifying the Energy Transition.” Source: RevenueBase Database · checked Sep 17, 2026
17	Homeworks Energy, INC	Indirect evidence	Medford, MA, United StatesHQ checked Sep 17, 2026	201-500	356 contacts →
	Indirect evidence “At HomeWorks Energy, our mission is simple, literally: Energy Efficiency, Simplified.” Source: RevenueBase Database · checked Sep 17, 2026
18	United Mechanical	Partial evidence	San Jose, CA, United StatesHQ checked Sep 17, 2026	201-500	346 contacts →
	Partial evidence “United Mechanical specializes in HVAC and Plumbing systems design, construction, retrofit, repair, and 24/7 emergency service for commercial and industrial properties throughout…” Source: RevenueBase Database · checked Sep 17, 2026
19	Sunbelt Controls	Strong evidence	Pleasanton, CA, United StatesHQ checked Sep 17, 2026	201-500	322 contacts →
	Strong evidence “Sunbelt Controls is a leading full-service building automation contractor for new construction and retrofit projects in the Western United States.” Source: RevenueBase Database · checked Sep 17, 2026
20	Villara Building Systems	Partial evidence	Mcclellan Park, CA, United StatesHQ checked Sep 17, 2026	1,001-5,000	303 contacts →
	Partial evidence “Villara is one of the nation’s largest mechanical contractors.” Source: RevenueBase Database · checked Sep 17, 2026
21	John E. Green Company	Indirect evidence	Highland Park, MI, United StatesHQ checked Sep 17, 2026	1,001-5,000	301 contacts →
	Indirect evidence “In 1909, John E.” Source: RevenueBase Database · checked Sep 17, 2026
22	Kimbel Mechanical Systems INC	Indirect evidence	Fayetteville, AR, United StatesHQ checked Sep 17, 2026	501-1,000	297 contacts →
	Indirect evidence “Kimbel Mechanical Systems, Inc.” Source: RevenueBase Database · checked Sep 17, 2026
23	The Hill Group	Partial evidence	Franklin Park, IL, United StatesHQ checked Sep 17, 2026	501-1,000	285 contacts →
	Partial evidence “The Hill Group is a Chicago-based mechanical contractor specializing in HVAC, plumbing, fire protection, testing/balancing, and commissioning.” Source: RevenueBase Database · checked Sep 17, 2026
24	Batchelor & Kimball, INC	Partial evidence	Conyers, GA, United StatesHQ checked Sep 17, 2026	1,001-5,000	270 contacts →
	Partial evidence “Batchelor & Kimball is a mechanical engineering and plumbing contractor specializing in projects that call for advanced expertise and problem-solving.” Source: RevenueBase Database · checked Sep 17, 2026
25	GEM Incorporated	Partial evidence	Walbridge, OH, United StatesHQ checked Sep 17, 2026	1,001-5,000	270 contacts →
	Partial evidence “Contractor for Life At GEM Inc, we’re experienced problem solvers with the insight, integrity and resources to see you through your toughest challenges.” Source: RevenueBase Database · checked Sep 17, 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: retrofit contractors. 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 retrofit contractors.
Partial evidence: Its own public description names part of retrofit contractors, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name retrofit contractors. 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 5,218 retrofit contractors based in the United States

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Retrofit contractors based in the United States at a glance

As of Sep 17, 2026

36.7%Verified-email coverage

12.5Average contacts per company

11-50Median size (employees)

2.5%Largest-city concentration · New York

Sep 17, 2026Page data refreshed

Companies by employee count

1-10

2,352

11-50

1,989

51-200

660

201-500

125

501-1,000

1,001-5,000

5,001-10,000

10001+

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 5,218 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 retrofit contractors, 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 “retrofit contractors”. 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 retrofit contractors), 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 retrofit contractors, 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, 23,994 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 17, 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.

Retrofit contractors 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 retrofit contractors, 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 retrofit contractors are there based in the United States?

RevenueBase identified 5,218 retrofit contractors 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?

Mckinstry, headquartered in Seattle, tops this list with the largest team on record.

Which city has the most retrofit contractors?

New York leads with 129 headquartered companies, followed by Houston (72) and Los Angeles (72).

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 23,994 verified decision-maker contacts tracked across these 5,218 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 17, 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.