Company lists · Data refreshed September 2026
Top 25 Net-zero retrofit consultants worldwide
RevenueBase identified 2,942 net-zero retrofit consultants worldwide as of September 2026 and tracks 21,912 professional contacts across them, including 7,727 with verified work emails. The United States is the largest market and London the largest hub.
This list covers net-zero retrofit consultants worldwide, 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 29, 2026. Country and city lists for net-zero retrofit consultants follow the table.
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.
The 25 largest net-zero retrofit consultants worldwide
Ranked by team size| # | Company | Contacts | |||
|---|---|---|---|---|---|
| 1 | 1,145 contacts → | ||||
Indirect evidence “OLA Sustainability, LLC OLA Sustainability is a consulting firm that focuses on integrating sustainable practices into commercial and multifamily design projects.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 2 | 342 contacts → | ||||
Indirect evidence “The National Energy Services Company (TARSHID) is a national company wholly owned by the Public Investment Fund (PIF).” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 3 | 317 contacts → | ||||
Indirect evidence “Climate change is without a doubt the greatest challenge we face in these times.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 4 | 253 contacts → | ||||
Indirect evidence Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 5 | 238 contacts → | ||||
Indirect evidence “At Ecosystem, we believe in building meaningful relationships with both our clients and employees.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 6 | 233 contacts → | ||||
Indirect evidence “As of November of 2025, AMA Group has merged with CMTA!” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 7 | 210 contacts → | ||||
Indirect 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 29, 2026Thanks. The Data Team will review it. | |||||
| 8 | 205 contacts → | ||||
Indirect evidence “Bright Power is a leading provider of energy efficiency and decarbonization solutions for the real estate industry.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 9 | 157 contacts → | ||||
Strong evidence “Zenergi supports and empowers your journey to net zero.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 10 | 149 contacts → | ||||
Indirect evidence “Accenta aide les acteurs de l’immobilier à maîtriser leurs charges, valoriser leurs actifs et répondre aux exigences réglementaires, grâce à la performance énergie-carbone.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 11 | 144 contacts → | ||||
Strong evidence “Trailblazing the way to net zero smart buildings Our cutting-edge PROActiv Solutions enhance the health, energy efficiency and sustainability of UK businesses and commercial…” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 12 | 142 contacts → | ||||
Indirect evidence “Optimised exists to accelerate the shift to a low-carbon future by making energy management work; commercially, operationally and sustainably.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 13 | 139 contacts → | ||||
Indirect evidence “Sénova est "le partenaire de la rénovation énergétique de votre habitat".” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 14 | 130 contacts → | ||||
Indirect evidence “Resalta is a leading European energy service company (ESCO) helping organizations reduce costs, lower emissions, and optimize energy use.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 15 | 129 contacts → | ||||
Partial evidence “Recognised as the Consultancy of the Year in 2021 by Energy Live News, Consultus delivers world-class consulting, buying and management services for Business Energy and Business…” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 16 | 128 contacts → | ||||
Indirect evidence “We Make Buildings Brilliant.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 17 | 125 contacts → | ||||
Indirect evidence “ecoworks is the trusted partner for the housing sector when it comes to affordable, energy-efficient renovations.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 18 | 123 contacts → | ||||
Strong evidence “OTC Flow is your partner in achieving net zero emissions, providing customized solutions for your financial-environmental obligations and aspirations.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 19 | 121 contacts → | ||||
Indirect evidence “Michaels Energy is a veteran-owned energy consulting firm that exists to help businesses minimize waste and maximize value.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 20 | 115 contacts → | ||||
Partial evidence “Longevity Partners is a multidisciplinary energy and sustainability consultancy.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 21 | 109 contacts → | ||||
Indirect evidence “EcoEngineers, an LRQA company, is a consulting, auditing, and advisory firm with an exclusive focus on the energy transition and decarbonization.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 22 | 108 contacts → | ||||
Indirect evidence Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 23 | 107 contacts → | ||||
Indirect 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 29, 2026Thanks. The Data Team will review it. | |||||
| 24 | 98 contacts → | ||||
Strong evidence “BOOTES - India’s 1st NET-ZERO Company.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 25 | 90 contacts → | ||||
Partial evidence “We are a leading provider of retrofit residential decarbonisation across the UK.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
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: net-zero retrofit consultants. 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 net-zero retrofit consultants.
- Partial evidence
- Its own public description names part of net-zero retrofit consultants, so it works in or next to the category without describing itself that way.
- Indirect evidence
- The description shown does not name net-zero retrofit consultants. 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 2,942 net-zero retrofit consultants worldwide
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Net-zero retrofit consultants worldwide at a glance
As of Sep 29, 2026Companies by employee count
Email recency is reported on each country list linked below.
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 net-zero retrofit consultants, 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.
- Coverage
- Every country. Country and city lists for net-zero retrofit consultants are linked below.
- What qualifies
- Companies worldwide whose own description of what they do matches “net-zero retrofit consultants”. 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 net-zero retrofit consultants), 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 net-zero retrofit consultants, and records with no verified work email.
- 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, 7,727 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 29, 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.
Net-zero retrofit consultants by location
17 lists · largest firstEvery Net-zero retrofit consultants list RevenueBase publishes, by country and city. Counts are matching companies in each list as of its own refresh date.
Countries
- Net-zero retrofit consultants based in the United States536
- Net-zero retrofit consultants based in the United Kingdom407
- Net-zero retrofit consultants based in France309
- Net-zero retrofit consultants based in Germany262
- Net-zero retrofit consultants based in Canada168
- Net-zero retrofit consultants based in Italy111
- Net-zero retrofit consultants based in Spain98
- Net-zero retrofit consultants based in the Netherlands60
- Net-zero retrofit consultants based in India58
- Net-zero retrofit consultants based in Australia54
- Net-zero retrofit consultants based in Switzerland42
- Net-zero retrofit consultants based in Belgium41
- Net-zero retrofit consultants based in Ireland31
Cities
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 net-zero retrofit consultants, 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 net-zero retrofit consultants are there worldwide?
RevenueBase identified 2,942 net-zero retrofit consultants worldwide 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?
OLA, headquartered in Austin, tops this list with the largest team on record.
Which country has the most net-zero retrofit consultants?
The United States leads with 536 companies, followed by the United Kingdom (407) and France (309). Every net-zero retrofit consultants list by country and city is linked on this page.
Which city has the most net-zero retrofit consultants?
London leads with 84 headquartered companies, followed by Paris (37) and New York (28).
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 7,727 verified decision-maker contacts tracked across these 2,942 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 29, 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.