Best Energy Efficiency Tech Companies in Ireland
The 59 best Energy Efficiency Tech companies in Ireland in 2026, ranked by funding and momentum. Funding, investors, founders, valuation, tech stack and live signals. Top: Exergyn.
Ireland's Energy Efficiency Tech sector has 59 companies on our radar, collectively pulling in $76M in disclosed equity funding, and the spread across those companies tells you exactly where the conviction is sitting right now. Exergyn leads the field at $35M, a number that's more than triple the combined totals of Viotas ($11M) and Cylon ($10M). No unicorns yet, but the funding stack isn't shallow either. Backers like Enterprise Ireland, ESB, and Europa are active across the cohort, which signals institutional appetite rather than a handful of isolated bets. And as 2018 research on next-generation energy systems makes clear, the efficiency transition isn't a slow burn, it's compressing fast.
So what's moving underneath the capital? Median install growth across energy apps is running at roughly +28% YoY, which I'd argue is the most underappreciated signal in the sector right now. Hot themes clustering around EV battery technology, solar electricity generation, and next-generation EV platforms are pulling coverage upward, and Ireland's grid-adjacent players are well-positioned to catch that current. If you're trying to map which companies have real funding momentum behind them, this is the list worth starting with.
Our analysis of 50 Energy Efficiency Tech companies
$7.8b in tracked funding; 86% of the stack-profiled cohort runs cloud-native; funding activity peaked in 2025.
Ranked: Best Energy Efficiency Tech companies in Ireland
| # | Company | Employees | Disclosed funding | Last round | Founder | Stage | Tech stack | Recent signals |
|---|---|---|---|---|---|---|---|---|
| 1 | Johnson Controls Manufacturer and supplier of automotive batteries and HVAC equipment | 100,000 100,000 → 60,114 (-40%) | — | 13 mo ago | George Oliver CEO | Public | SitecoreSentryTypeScript+44 | 1 launch · 1 award |
| 2 | PrePayPower Pay-as-you-go electricity and gas retailer | 437 | $7M | 156 mo ago | Cathal Fay CEO | Series A | RubyTrixYouTube+17 | 5 job openings · 1 internship |
| 3 | Hanley Energy Building energy consumption tracking solution provider | 247 | — | — | Clive Gilmore Co-Founder & CEO | Acquired | WordPressMySQLPHP+22 | 1 partnership · 1 award |
| 4 | Smart Efficient Light Control Provider of street lighting monitoring solutions | 200 | $3M | 192 mo ago | — | Acqui-Hired | — | — |
| 5 | VIOTAS Provider of smart grid and demand response technology | 117 | $11M | 13 mo ago | — | Funding Raised | WordPress Block EditorWordPressMySQL+22 | 1 job opening |
| 6 | Cylon Provider of multi-site building energy management systems | 100 | $10M | 144 mo ago | — | Acqui-Hired | — | — |
| 7 | Exergyn Waste Heat to energy converter | 36 | $35M | 53 mo ago | Kevin Toole Co-Founder & CTO | Series A | WordPressMySQLPHP+9 | 2 expansions |
| 8 | horizon energy group Horizon Energy was founded in Ireland in 2006. As one of the first energy consultants working with the… | 27 | — | — | — | Acquired | — | — |
| 9 | ResourceKraft Data analytics for energy management | 20 | $808K | 194 mo ago | Liam Relihan Co-Founder & CEO | Seed | — | — |
| 10 | Climote Provider of heating control systems | 18 | $2M | 92 mo ago | Derek Roddy Co-Founder & CEO | Seed | OpenSSLBootstrapApache HTTP Server+10 | — |
| 11 | Ceramicx Manufacturer of infrared heating systems | 17 | $281K | 129 mo ago | Frank Wilson Co-Founder & Managing Director | Acquired | Cart FunctionalityWooCommerceWordPress+32 | 1 job opening · 1 launch · 1 award |
| 12 | Wattics Cloud based analytics solutions for monitoring appliances and equipments | 13 | $984K | 109 mo ago | — | Acqui-Hired | — | — |
| 13 | VT Electron Company provides grid monitoring solutions for grid operators | 12 | $1M | 122 mo ago | Mark Bannon Founder & CEO | Seed | — | — |
| 14 | KelTech IoE Provider of smart solutions for the communications infrastructure and property technology market | 12 | — | — | Mark Kellett Founder & CEO | Unfunded | — | — |
| 15 | SureWash Hand hygiene training and compliance measurement | 11 | $827K | 151 mo ago | — | Seed | WordPressMySQLPHP+29 | — |
Top 12 Energy Efficiency Tech companies in Ireland
#1
Funding Raised · Limerick, County Limerick · founded 2013 · 117 employees$11.4Mraised▾
Provider of smart grid and demand response technology. It offers demand response solutions that allows commercial and industrial operations to earn revenue by participating in the electricity market.
- May 2025Conventional Debt$11.4M
#2
Series A · Dublin, Leinster · founded 2012 · 36 employees$35.1Mraised▾
Waste Heat to energy converter. It offers a form of waste heat exchanger which helps in converting low-grade waste heat LGWH into a usable form. The technology is particularly suited to industrial applications like combined heat power, biogas, cargo shipping, and more.
- Jan 2022Series A$35M
- May 2017Grant (prize money)$2.8M
- Jun 2015Grant (prize money)$2.7M
- May 2015Grant (prize money)$2.8M
#3
Acqui-Hired · Dublin, Leinster · founded 1985 · 100 employees$9.6Mraised▾
Cylon provides integrated building energy management systems. It designs hardware and software solutions to control, monitor and maintain building environment, maintaining occupant comfort, and more. The company offers 'Cylon Active Energy' - a SaaS-based building energy monitoring system that provides real-time information on energy usage and consumption in a building. Additionally, it also offers energy management tools with features such as charting, analysis, reports, monitoring & alarms, data collection, branding, and more. The company also collects data form wired & wireless sensors.
#4
Funding Raised · Galway, Galway · founded 2012$1.7Mraised▾
Sparkworks offers edge computing-based full stack IoT platform and programmable APIs. It includes device connector, event and rule processor, storage services, etc. Offers features like ready-to-use mobile applications, real-time IoT data analysis for intelligent interaction, fast data access, open design, easy reconfiguration across different wearable devices, a minimum response time for critical products, and others. Its platform can drive RaspberryPi and a 433MHz transmitter to control RF devices for various integrated solutions like smart buildings, smart cities, hi-end wearables, etc.
- Jan 2021Grant (prize money)$522.7K
- Jan 2019Grant (prize money)$507.5K
- Jan 2018Grant (prize money)$378.8K
- Jan 2017Grant (prize money)$123K
#5
Series A · Dublin, Leinster · founded 2009 · 437 employees$6.6Mraised▾
Pay-as-you-go electricity and gas retailer. The company provides electricity and gas on a pay-as-you-go basis. The company provides its customers with a meter and a smartphone app. The users can top-up the electricity using the app. The app provides information on energy usage and pricing.
- Jun 2013Series A$6.6M
#6
Acqui-Hired · Mayo, County Mayo · founded 1983 · 200 employees$3.1Mraised▾
SELC manufactures electronic controllers for street lighting which includes ballasts, photocells, communications systems, powerline, wireless central monitoring systems, and time clocks. Its solutions optimize the switching on and off, dimming of street lights, and can adjust the intensity of lighting based on prevailing conditions. The products power the lamp with a unique waveform so as to increase its life, predict in advance when the lamp will fail and communicate this information to a central management system, thus assisting in lighting maintenance programs.
#7
Seed · Dundalk, County Louth · founded 2011 · 18 employees$1.7Mraised▾
Provider of heating control systems. Using the climote remote, the user can set up to three zones for heating control or two zones and hot water control. It has an sms built in allowing control via text, online using a computer or through a smartphone app for Android and iOS.
- Nov 2018Seed$1.7M
- Apr 2015Grant (prize money)$53.8K
#8
Acqui-Hired · Dublin, Leinster · founded 2011 · 13 employees$983.5Kraised▾
Wattics provides software solution to monitor and manage the electrical consumption of machines and appliances in industrial and commercial sites. They offer cloud-based analytics solutions for customers with meter or without meters and propose turnkey solutions to improve savings.
- Jun 2017Grant (prize money)$180.7K
- Jan 2017Grant (prize money)$169.7K
- Sep 2016Grant (prize money)$225.6K
- Mar 2016Grant (prize money)$407.5K
#9
Seed · Glasnevin, Leinster · founded 2014 · 12 employees$1.4Mraised▾
Company provides grid monitoring solutions for grid operators. It also offers tools for capturing remote data and asset analysis. It also developing and deploying IoT for zero carbon neutrality.
#10
Seed · Limerick, County Limerick · founded 2007 · 6 employees$1.1Mraised▾
Episensor has developed sensor systems for demand response and energy management applications. The system collects data from the power grids and industrial environments which is relayed to cloud platform and then displayed on an intuitive interface for data visualization at the customer end. Data collectors like wireless probe temperature sensor, electricity consumption monitor send data to the gateway via ZigBee network. User can also add other sensor nodes to the gateway and schedule a time for exporting.
- Dec 2011Seed$1.1M
#11
Seed · Dublin, Leinster · founded 2011 · 11 employees$827Kraised▾
SureWash provides a gesture recognition technology based hand-hygiene quality management system. The system helps healthcare management audit every hand wash, provide Hand Hygiene training with patented video measurement technology and customised management reporting on hand-washing performance. The company, a spin-out of Trinity College, is backed by Enterprise Ireland and New Leaf Investments.
- Dec 2013Seed$827K
#12
Acqui-Hired · Dublin, Leinster · founded 2016$620Kraised▾
Provider of LED light source modules. The module is in the form of a tile that produces a surface of white light and can be fixed to lightings and luminaires. It is developed using its patent-pending technology that combines the thin features of OLED.
- Apr 2018Seed$620K
Funding & investor landscape
Notable founders
Market landscape — 10 sub-themes by coverage
Share of Energy Efficiency Tech coverage by sub-theme.
Regulatory-risk over time rising
Funding & growth over time
funding flat · growth flat
How research on Energy Efficiency & Buildings is moving in Ireland
A read on the academic research around Energy Efficiency & Buildings — which themes are gaining ground, the institutions and researchers driving them, and how the tone is shifting. Based on 100 Ireland-affiliated papers.
- University College Dublin25
- Trinity College Dublin11
- University of Limerick11
- Technological University Dublin9
- University College Cork8
- Energy management2→6
- Efficient energy use2→4
- Heat pump3→14
- Renewable energy1→8
- Electricity1→8
- Thermal energy storage1→5
- Passive cooling1→4
- Heat pump8
- Air source heat pumps3
- Heat exchanger3
- Thermal comfort2
- Thermal energy storage2
Where energy efficiency is researched across Ireland
Location clusters by institution affiliation — each city's volume, stance tone, and a quick read on its hot topic, what's advancing, the opening opportunity, and the main concern.
Common questions
Rohit lives in the feed. He covers what's moving right now — the funding rounds, launches and shifts breaking across the trade press — and ties them back to where the sector is heading.