Company lists · Data refreshed September 2026

Top 25 Geothermal system designers worldwide

RevenueBase identified 4,408 geothermal system designers worldwide as of September 2026 and tracks 26,880 professional contacts across them, including 7,542 with verified work emails. The United States is the largest market and Madrid the largest hub.

This list covers geothermal system designers 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 19, 2026. Country and city lists for geothermal system designers 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.

How to read this list HQ checked on every row RevenueBase Smart Search rating on every row Refreshed Sep 19, 2026 86% judged on-target in blind review
4,408Companies
26,880Contacts tracked
7,542Verified emails
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The 25 largest geothermal system designers worldwide

Ranked by team size
Top 25 of 4,408 geothermal system designers worldwide, ranked by team size, largest first. Data refreshed Sep 19, 2026. RevenueBase Smart Search rates how each company's information relates to geothermal system designers: 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.
#CompanyRevenueBase Smart SearchHeadquartersEmployeesContacts
1Indirect evidenceReno, NV, United StatesHQ checked Sep 19, 20261,001-5,0001,281 contacts →

Indirect evidence

“With over five decades of experience, Ormat Technologies, Inc.”

Source: RevenueBase Database · checked Sep 19, 2026
2Indirect evidenceWarwick, United KingdomHQ checked Sep 19, 20261,001-5,000850 contacts →

Indirect evidence

“We're leading the energy transition to zero carbon, by offering complete residential and commercial heating and hot water solutions.”

Source: RevenueBase Database · checked Sep 19, 2026
3Partial evidenceSan Bonifacio, ItalyHQ checked Sep 19, 20261,001-5,000418 contacts →

Partial evidence

“Comfort, designed around you – Since 1955, Ferroli has been a trusted name in HVAC, delivering innovative solutions for heating, cooling and hot water that combine comfort, energy…”

Source: RevenueBase Database · checked Sep 19, 2026
4Indirect evidenceKennesaw, GA, United StatesHQ checked Sep 19, 2026201-500231 contacts →

Indirect evidence

“Since 1978, Reliable Heating & Air has been serving all of Metro Atlanta's communities offering heating, cooling, plumbing and electrical services, indoor air quality, duct…”

Source: RevenueBase Database · checked Sep 19, 2026
5Indirect evidenceFort Wayne, IN, United StatesHQ checked Sep 19, 2026201-500224 contacts →

Indirect evidence

“WaterFurnace International, Inc.”

Source: RevenueBase Database · checked Sep 19, 2026
6Indirect evidenceDenver, CO, United StatesHQ checked Sep 19, 2026201-500220 contacts →

Indirect evidence

“Tolin Mechanical is a Leading Energy & Commercial HVAC Services Company.”

Source: RevenueBase Database · checked Sep 19, 2026
7Indirect evidenceLititz, PA, United StatesHQ checked Sep 19, 2026201-500191 contacts →

Indirect evidence

“Since 1981, Haller Enterprises has proudly served central and eastern Pennsylvania as a leader in heating, cooling, plumbing, and electrical services.”

Source: RevenueBase Database · checked Sep 19, 2026
8Indirect evidenceDania Beach, FL, United StatesHQ checked Sep 19, 2026201-500168 contacts →

Indirect 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 19, 2026
9Indirect evidenceVoorburg, NetherlandsHQ checked Sep 19, 202651-200149 contacts →

Indirect evidence

“Eteck levert duurzame energie in de vorm van koude en warmte.”

Source: RevenueBase Database · checked Sep 19, 2026
10Indirect evidenceMontpellier, FranceHQ checked Sep 19, 2026201-500132 contacts →

Indirect evidence

Source: RevenueBase Database · checked Sep 19, 2026
11Partial evidenceIcelandHQ checked Sep 19, 202651-200128 contacts →

Partial evidence

“ABOUT http://iceland-drilling.com/ Iceland Drilling Ltd is a leading high technical company in the field of high temperature geothermal drilling and has many decades of experience…”

Source: RevenueBase Database · checked Sep 19, 2026
12Indirect evidenceAnkara, TürkiyeHQ checked Sep 19, 20261,001-5,000124 contacts →

Indirect evidence

“Bilgi birikimini yatırıma ve tasarrufa dönüştürmek için çalışmalarını 1990 yılından bu yana sürdüren Doğan Jeotermal Group ülkemizin sahip olduğu jeotermal enerji kaynaklarını…”

Source: RevenueBase Database · checked Sep 19, 2026
13Partial evidenceMount Kisco, NY, United StatesHQ checked Sep 19, 202651-200118 contacts →

Partial evidence

“Dandelion Energy is the nation’s leading residential geothermal provider, on a mission to make the world’s most efficient heating and cooling technology accessible to everyone.”

Source: RevenueBase Database · checked Sep 19, 2026
14Indirect evidenceStratford, CT, United StatesHQ checked Sep 19, 2026201-500110 contacts →

Indirect evidence

“At ENCON, we take care of people.”

Source: RevenueBase Database · checked Sep 19, 2026
15Indirect evidenceArmonk, NY, United StatesHQ checked Sep 19, 202651-200108 contacts →

Indirect evidence

“Brightcore Energy is a leading renewable energy solutions provider serving commercial, institutional, and government clients.”

Source: RevenueBase Database · checked Sep 19, 2026
16Indirect evidenceAthens, GreeceHQ checked Sep 19, 2026201-500105 contacts →

Indirect evidence

“SYCHEM S.A.”

Source: RevenueBase Database · checked Sep 19, 2026
17Indirect evidenceLons, FranceHQ checked Sep 19, 2026201-50089 contacts →

Indirect evidence

“Fondée en 1983 par Patrice Bobion (artisan électricien) et Jean-Pierre Joanin (artisan plombier) l’entreprise Bobion & Joanin est devenue en près de 40 ans un acteur majeur du…”

Source: RevenueBase Database · checked Sep 19, 2026
18Indirect evidenceRound Rock, TX, United StatesHQ checked Sep 19, 202651-20089 contacts →

Indirect evidence

“CASA Mechanical is owned and operated by the W.G.”

Source: RevenueBase Database · checked Sep 19, 2026
19Partial evidenceWien, AustriaHQ checked Sep 19, 2026201-50087 contacts →

Partial evidence

“Vaillant Österreich bietet #energiesparende und #umweltschonende Systeme für #Heizen,#Kühlen und #Warmwasser.”

Source: RevenueBase Database · checked Sep 19, 2026
20Indirect evidencePhelps, NY, United StatesHQ checked Sep 19, 202651-20082 contacts →

Indirect evidence

“Halco is a highly accredited, national award-winning contractor that has been providing high-quality solutions to residential and commercial clients since 1984.”

Source: RevenueBase Database · checked Sep 19, 2026
21Partial evidenceGreenville, IL, United StatesHQ checked Sep 19, 202651-20081 contacts →

Partial evidence

“Enertech Global is a leading manufacturer and visionary in the geothermal heating and cooling industry.”

Source: RevenueBase Database · checked Sep 19, 2026
22Indirect evidenceTulsa, OK, United StatesHQ checked Sep 19, 2026201-50081 contacts →

Indirect evidence

“Hayden is a technology and engineering company that builds critical infrastructure for compute, energy and thermal performance.”

Source: RevenueBase Database · checked Sep 19, 2026
23Indirect evidenceClamart, FranceHQ checked Sep 19, 202651-20079 contacts →

Indirect evidence

“The Earth can accumulate summer heat and reuse it in the winter, so energy can be stored from season to season.”

Source: RevenueBase Database · checked Sep 19, 2026
24Partial evidenceBozeman, MT, United StatesHQ checked Sep 19, 2026201-50072 contacts →

Partial evidence

“Energy 1 designs and installs state-of-the-art Mechanical, Electrical, and Plumbing systems that utilize renewable technologies and deliver efficiency, elegance, and legacies our…”

Source: RevenueBase Database · checked Sep 19, 2026
25Partial evidenceCopenhagen, DenmarkHQ checked Sep 19, 202651-20069 contacts →

Partial evidence

“Energy Machines is a leading provider of integrated energy systems that decarbonize heating and cooling while reducing operating costs for real estate owners, municipalities, and…”

Source: RevenueBase Database · checked Sep 19, 2026

Showing 25 of 4,408 geothermal system designers worldwide

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Geothermal system designers worldwide at a glance

As of Sep 19, 2026
28.1%Verified-email coverage
6.1Average contacts per company
1-10Median size (employees)
0.5%Largest-city concentration · Madrid
Sep 19, 2026Page data refreshed

Companies by employee count

1-10
2,396
11-50
1,547
51-200
314
201-500
39
501-1,000
6
1,001-5,000
8
5,001-10,000
1
10001+
4

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 geothermal system designers, 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 geothermal system designers are linked below.
What qualifies
Companies worldwide whose own description of what they do matches “geothermal system designers”. 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 geothermal system designers), 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 geothermal system designers, 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, 7,542 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 19, 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.

Geothermal system designers by location

17 lists · largest first

Every Geothermal system designers list RevenueBase publishes, by country and city. Counts are matching companies in each list as of its own refresh date.

Countries

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 geothermal system designers, 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 geothermal system designers are there worldwide?

RevenueBase identified 4,408 geothermal system designers 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?

Ormat Technologies, INC, headquartered in Reno, tops this list with the largest team on record.

Which country has the most geothermal system designers?

The United States leads with 816 companies, followed by France (449) and Germany (377). Every geothermal system designers list by country and city is linked on this page.

Which city has the most geothermal system designers?

Madrid leads with 23 headquartered companies, followed by London (21) and Roma (19).

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 7,542 verified decision-maker contacts tracked across these 4,408 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 19, 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.