Company lists · Data refreshed November 2026

Top 25 Retrofit engineering consultants based in the United States

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

Compiled by the RevenueBase Data Team Data refreshed Nov 6, 2026 6,060 companies tracked

RevenueBase identified 6,060 company matches for retrofit engineering consultants associated with the United States as of November 2026 and tracks 199,709 professional contacts across them, including 102,538 with verified work emails. New York is the largest hub.

This list covers company matches for retrofit engineering consultants associated with the United States, found by RevenueBase SmartSearch using the meaning of business descriptions in its company graph at Exact. Ranked by professionals tracked, largest first. Rows show recorded descriptions where available, Exact search membership and the snapshot date. Data refreshed November 6, 2026.

Published by RevenueBase, a B2B data infrastructure company. This list was built with RevenueBase SmartSearch, 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 SmartSearch · Exact Recorded Nov 6, 2026 How this list was built

6,060Companies

199,709Contacts tracked

102,538Verified emails

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The 25 largest retrofit engineering consultants based in the United States

Ranked by team size

Top 25 of 6,060 company matches for retrofit engineering consultants based in the United States, ordered by professional contacts tracked in RevenueBase, largest first. Recorded Nov 6, 2026. The RevenueBase SmartSearch column shows Exact match membership in this saved search. Click a contact count to view that company's people. Totals use company locations recorded by RevenueBase; the displayed preview is a smaller selection.
#	Company	RevenueBase SmartSearch	Headquarters	Employees	Contacts
1	Terracon	Exact match	Olathe, NE, United StatesHQ recorded Nov 6, 2026	5,001-10,000	6,576 contacts →
	Exact match “Terracon is a 100 percent employee-owned consulting engineering firm providing quality services to clients.” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
2	Langan Engineering & Environmental Services	Exact match	Parsippany, TN, United StatesHQ recorded Nov 6, 2026	1,001-5,000	2,492 contacts →
	Exact match “Langan's client-focused, highly entrepreneurial culture cultivates an environment of opportunities in which career growth and teamwork flourish.” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
3	ECS Group Of Companies	Exact match	Chantilly, VA, United StatesHQ recorded Nov 6, 2026	1,001-5,000	2,363 contacts →
	Exact match “ECS Group of Companies is a Chantilly, VA-based consulting engineering firm.” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
4	Olsson	Exact match	Lincoln, AR, United StatesHQ recorded Nov 6, 2026	1,001-5,000	2,289 contacts →
	Exact match “Olsson is an engineering firm made up of people who craft expert solutions and designs that improve communities.” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
5	LJA	Exact match	Griffin, GA, United StatesHQ recorded Nov 6, 2026	1,001-5,000	2,206 contacts →
	Exact match “Employee-Owned.” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
6	Colliers Engineering & Design	Exact match	Holmdel, NC, United StatesHQ recorded Nov 6, 2026	1,001-5,000	2,172 contacts →
	Exact match “Colliers Engineering & Design, an affiliate of Colliers, is a trusted provider of multi-discipline engineering and architecture, design and consulting services to public and…” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
7	IMEG	Exact match	Rock Island, IL, United StatesHQ recorded Nov 6, 2026	1,001-5,000	2,116 contacts →
	Exact match “Leaders in Engineering and Innovation.” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
8	Salas O'brien	Exact match	Irvine, CA, United StatesHQ recorded Nov 6, 2026	1,001-5,000	2,110 contacts →
	Exact match “Salas O’Brien is an employee-owned engineering, science, and technical services firm focused on advancing the human experience through the built environment.” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
9	Westwood Professional Services	Exact match	Plano, TX, United StatesHQ recorded Nov 6, 2026	1,001-5,000	1,849 contacts →
	Exact match “At Westwood, our purpose is to create a better world for people through our work.” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
10	Bowman Consulting	Exact match	Reston, VA, United StatesHQ recorded Nov 6, 2026	1,001-5,000	1,827 contacts →
	Exact match “Headquartered in Reston, Virginia, Bowman is a national engineering services firm delivering infrastructure solutions to customers who own, develop and maintain the built…” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
11	CHA Consulting, INC	Exact match	Albany, NH, United StatesHQ recorded Nov 6, 2026	1,001-5,000	1,780 contacts →
	Exact match “CHA Consulting, Inc.(CHA) is an innovative, full-service engineering, design, consulting, and program/construction management firm providing a wide range of technology-enhanced…” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
12	JMT	Exact match	Serving Clients Across The Us, NJ, United StatesHQ recorded Nov 6, 2026	1,001-5,000	1,771 contacts →
	Exact match “JMT is an employee owned, multi-disciplined firm offering a full array of planning, design, and construction phase consulting services for infrastructure projects throughout the…” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
13	UES	Exact match	Orlando, FL, United StatesHQ recorded Nov 6, 2026	1,001-5,000	1,694 contacts →
	Exact match “UES provides professional engineering, environmental, testing and inspection services to clients across the United States.” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
14	GEI Consultants, INC	Exact match	Woburn, MA, United StatesHQ recorded Nov 6, 2026	1,001-5,000	1,675 contacts →
	Exact match Recorded description not available. Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
15	Atwell, LLC	Exact match	Southfield, MI, United StatesHQ recorded Nov 6, 2026	1,001-5,000	1,561 contacts →
	Exact match “Atwell is a full-service consulting, engineering and construction services firm that delivers a broad range of creative solutions to clients in the real estate and land…” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
16	Ulteig	Exact match	Fargo, IA, United StatesHQ recorded Nov 6, 2026	1,001-5,000	1,491 contacts →
	Exact match “Ulteig delivers comprehensive design engineering, program management and technical and field services that strengthen infrastructure vital to everyday life.” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
17	Partner Engineering & Science, INC	Exact match	Torrance, WA, United StatesHQ recorded Nov 6, 2026	1,001-5,000	1,481 contacts →
	Exact match “Partner Assessment Corp.” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
18	Davey Resource Group, INC	Exact match	Kent, OH, United StatesHQ recorded Nov 6, 2026	1,001-5,000	1,477 contacts →
	Exact match “Davey Resource Group, Inc.(DRG) provides innovative consulting and field services that support utility infrastructure and environmental stewardship.” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
19	Walter P Moore	Exact match	Houston, TX, United StatesHQ recorded Nov 6, 2026	1,001-5,000	1,446 contacts →
	Exact match “Welcome to Walter P Moore!” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
20	GPI Greenman-Pedersen, INC	Exact match	Melville, FL, United StatesHQ recorded Nov 6, 2026	1,001-5,000	1,401 contacts →
	Exact match “With a staff of over 1,800 professionals, Greenman-Pedersen, Inc.(GPI) is a leading engineering consulting firm that specializes in the innovative design and construction of…” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
21	Pennoni	Exact match	Philadelphia, DE, United StatesHQ recorded Nov 6, 2026	1,001-5,000	1,322 contacts →
	Exact match “Since our founding more than five decades ago, our clients trust Pennoni’s commitment to elevating the impact of projects on our communities.” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
22	Apex Companies	Exact match	Rockville, MD, United StatesHQ recorded Nov 6, 2026	1,001-5,000	1,321 contacts →
	Exact match “Who is Apex?” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
23	Volkert, INC	Exact match	Mobile, AL, United StatesHQ recorded Nov 6, 2026	1,001-5,000	1,244 contacts →
	Exact match “Volkert’s history began in 1925 when it was founded in New Orleans as Doullut & Erwin to provide waterfront and heavy construction services, as well as airport design services…” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
24	Haley & Aldrich	Exact match	Burlington, MA, United StatesHQ recorded Nov 6, 2026	501-1,000	1,208 contacts →
	Exact match “Haley & Aldrich is committed to solving our clients’ most meaningful challenges in the built and natural environments.” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
25	Affiliated Engineers, INC	Exact match	Madison, IL, United StatesHQ recorded Nov 6, 2026	1,001-5,000	1,099 contacts →
	Exact match “Affiliated Engineers, Inc.(AEI) provides engineering leadership and whole-mission solutions for complex building, energy, and utility projects.” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase

RevenueBase SmartSearch

Describe a niche business in your own words. RevenueBase SmartSearch compares the meaning of your description with company business descriptions compiled in the RevenueBase company graph. Exact, Similar, Related and Broad control how closely companies must fit.

This list uses Exact for “retrofit engineering consultants”. Each Exact match badge shows membership in that saved search; it is not an individual similarity score or a service-quality rating. Recorded descriptions are shown where available.

Showing 25 of 6,060 retrofit engineering consultants based in the United States

See the full list, filter by size, metro and specialty, and access 102,538 tracked professional contacts with verified work emails. Direct dials are available where recorded.

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Retrofit engineering consultants based in the United States at a glance

As of Nov 6, 2026

51.3%Verified-email coverage

33.0Average contacts per company

11-50Median size (employees)

3.8%Largest-city concentration · New York

Nov 6, 2026Page data refreshed

Companies by employee count

1-10

2,959

11-50

2,169

51-200

683

201-500

141

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 6,060 companies.

How this list was built

The recorded descriptions help you assess these company matches. Check a company’s website for its current services and locations.

Source: The RevenueBase company graph: 60 million companies and 398.9 million professional contacts resolved from primary sources, queried with RevenueBase SmartSearch, the natural-language company search available to every RevenueBase user.
What qualifies: Company records associated with the United States whose business descriptions match “retrofit engineering consultants” by meaning at the Exact setting. Descriptions are compiled in the RevenueBase company graph from public websites, profiles and company information where available; they are not guaranteed quotations from the company's website.
RevenueBase SmartSearch: Describe a niche company in your own words to find businesses by meaning. Exact, Similar, Related and Broad control the breadth of RevenueBase SmartSearch. This saved list uses Exact. Each row's Exact match badge shows inclusion in that search, not an individual score or a service-quality judgment.
Public preview: The public preview omits records without a verified work email. Where headquarters information is recorded, preview rows are also filtered to this page’s location. Dataset totals and geographic summaries describe the full matched records before these preview filters.
Match quality: RevenueBase's August 25, 2026 study assessed 4,198 description/company pairs across matching settings. The publisher reports 86% good or better at Exact. This evaluates the method across queries; it does not audit this individual list. Recorded company descriptions, where available, help you judge each match yourself. Read the full methodology: how the lists are built and what the study measures.
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 displayed company carries at least one verified work email. RevenueBase tracks 102,538 professional contacts with verified work emails across the full matched dataset. 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 November 6, 2026. Lists refresh periodically as the graph is re-checked.
Record context: Company records and descriptions can change. Check the company's website for its current services and locations.

Retrofit engineering consultants by metro

Frequently asked

What is RevenueBase SmartSearch?

RevenueBase SmartSearch finds niche companies by the meaning of their business descriptions in the RevenueBase company graph. Exact, Similar, Related and Broad control how closely companies must fit your description. This list uses Exact for “retrofit engineering consultants”; each Exact match badge shows search membership, not an individual similarity or quality score.

How many retrofit engineering consultants are there based in the United States?

RevenueBase identified 6,060 company matches for retrofit engineering consultants associated with the United States as of November 2026, using the meaning of business descriptions at Exact. This is the recorded matched set in the RevenueBase company graph.

What is the largest company on this list?

Terracon tops the displayed preview by professional contacts tracked in RevenueBase. Recorded headquarters appear in the company rows.

Which city has the most retrofit engineering consultants?

New York leads with 233 company records, followed by Houston (134) and Chicago (76).

How do I get contact information for these companies?

A free RevenueBase account lets you run this exact search and work limited free results with 500 credits to start. Upgrading provides access to the 102,538 professional contacts with verified work emails tracked across these 6,060 companies; direct dials are available where recorded.

How current is this list?

The list refreshes periodically as the company graph is re-checked. This page's figures were pulled on November 6, 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 SmartSearch, 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.