Company lists · Data verified August 2026

Top 25 Energy efficiency investment firms based in the United Kingdom

Name: Energy efficiency investment firms based in the United Kingdom
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Verified Aug 28, 2026 243 companies tracked

There are 243 energy efficiency investment firms headquartered in the United Kingdom (RevenueBase, August 2026). RevenueBase tracks 1,967 professional contacts across them, including 773 with verified work emails and 134 with mobile numbers. London is the largest hub.

This list covers energy efficiency investment firms headquartered in the United Kingdom, matched on what each company actually does as described in its own words. Ranked by team size, largest first. Data current as of August 28, 2026.

243Companies

1,967Contacts tracked

773Verified emails

134Mobile numbers

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The 25 largest energy efficiency investment firms based in the United Kingdom

Ranked by team size

Top 25 of 243 energy efficiency investment firms based in the United Kingdom, ranked by team size, largest first. Data verified Aug 28, 2026. Click a count to unlock that company's people.
#	Company	HQ	Employees	Contacts	Verified emails
1	Octopus Energy Generation	London	201-500	152	104
2	Cenergist	Washington	201-500	63	35
3	Greengen	London	11-50	59	38
4	Energy Drive	London	51-200	59	19
5	Aura Power	Bristol	11-50	58	43
6	The Improveasy Group	Altrincham Manchester	51-200	57	38
7	Carb0n	London	11-50	56	38
8	Cotswold Energy Group	Stonehouse	51-200	46	24
9	Cotopaxi LTD	Skelmersdale	11-50	42	26
10	Bluewater	London	11-50	38	21
11	Zestec Renewable Energy	Bournemouth	11-50	28	2
12	Larkfleet Group Part Of Phoenix Sustainable Investments	Bourne	11-50	26	5
13	Green Energy International Limited	Cheadle Hulme	11-50	25	4
14	Lawler Sustainability	London	11-50	24	16
15	Pash Global	London	11-50	22	9
16	Making Energy Greener	Southport	51-200	21	14
17	Boom Power	Arundel	11-50	18	13
18	RMS Energy Solutions	Coventry	11-50	15	6
19	Victory Hill Capital Partners LLP	London	11-50	14	10
20	Energy Gain UK	Manchester	11-50	14	10
21	Helios Energy Investments	London	11-50	14	9
22	United Capital	London	501-1,000	14	4
23	HYCAP	Oxford	11-50	13	11
24	Susten	London	11-50	11	4
25	Carbon Saving Group	n/a	11-50	9	5

Showing 25 of 243 energy efficiency investment firms based in the United Kingdom

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Energy efficiency investment firms based in the United Kingdom at a glance

As of Aug 28, 2026

1-10Median size (employees)

LondonLargest hub · 90 HQs

134Contacts with mobile numbers

0Emails re-verified in last 30 days

Companies by employee count

1-10

137

11-50

51-200

201-500

501-1,000

1,001-5,000

5,001-10,000

Energy efficiency investment firms by metro

Metro	Companies
Energy efficiency investment firms in London	90
Energy efficiency investment firms in Manchester	10
Energy efficiency investment firms in Cambridge	3
Energy efficiency investment firms in Birmingham	3
Energy efficiency investment firms in Bristol	3
Energy efficiency investment firms in Harrogate	3
Energy efficiency investment firms in Nottingham	3

How this list was built

Source: The RevenueBase company graph: 21.3 million companies and 398.9 million professional contacts resolved from primary sources.
Inclusion: Companies whose own business descriptions match “energy efficiency investment firms”, with match quality audited by blind human judging, and headquartered in the United Kingdom.
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: Contact records re-verify on a rolling cadence; 0 contacts on this list were re-verified in the last 30 days.
Refresh: Lists are refreshed periodically as the underlying company graph is re-verified. Last verified Aug 28, 2026.

Frequently asked

How many energy efficiency investment firms are there based in the United Kingdom?

There are 243 energy efficiency investment firms headquartered in the United Kingdom as of August 2026 (RevenueBase).

What is the largest company on this list?

Octopus Energy Generation, headquartered in London, tops this list with the largest team on record.

Which city has the most energy efficiency investment firms?

London leads with 90 headquartered companies, followed by Manchester (10) and Cambridge (3).

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 773 verified decision-maker contacts tracked across these 243 companies.

How current is this list?

The list is refreshed periodically as the underlying company graph is re-verified. It was last verified on August 28, 2026.

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Energy efficiency investment firms by geography

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About this data

RevenueBase is a B2B contact data platform. Its company graph covers 21.3 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, the same data that powers RevenueBase's B2B data products and the free research portal.