Sunamp, the thermal battery storage technologies company, has received a £6 million convertible loan note investment from the Scottish National Investment Bank. Sunamp will use these funds to scale up production, increase its sales in the UK, and to accelerate international expansion into China, the Americas and continental Europe. Sunamp plans to launch a larger series B fund raising in the coming months. The Bank’s investment will support Sunamp as it works towards this larger fund raising.

Sunamp is already active in 17 countries and has so far shipped over 15 thousand thermal stores for the residential market from its UK manufacturing facility on the outskirts of Edinburgh. It recently opened new premises in Zurich and will open its first overseas manufacturing facility under licence in Korea in October 2021.

Sunamp’s compact thermal stores (or batteries) are designed to have a lifespan of up to 50 years, and to be highly circular in their product life cycle. The product range includes the world’s most compact and most energy efficient alternative to hot water cylinders and storage water heaters. Connected to renewable energy sources, Sunamp heat batteries support net zero heating and hot water, using less energy than other forms of thermal storage, and taking up a fraction of the space. Utility companies and their customers can benefit by using these compact thermal stores to support demand response for heating as an alternative to new network infrastructure investment to replace gas heating systems.

By harnessing innovation and enabling the adoption of renewable energy, the investment in Sunamp aligns with the Bank’s missions to support Scotland’s transition to net zero and invest in innovation and technologies of the future for a healthier, more resilient and productive population.

In addition to global expansion, the Bank’s investment will support Sunamp to enhance its product line into large mobile and static thermal batteries for improving efficiencies of heating and cooling for business and industry, bolstering its workforce at home and abroad and further developing its solutions to drive fuel economy up and carbon emissions down for the automotive industry.

Andrew Bissell, Sunamp Chief Executive, said: “The Bank and Sunamp share a vision of a world powered by affordable and sustainable energy. The Bank understands and supports the role our thermal technologies will play in accelerating the adoption of renewables in the transition to net zero. We are passionate about what we do, and the Bank’s investment is a strong vote of confidence in our strategy and our capability to become a significant global player in transforming how we heat and cool our buildings.

“With this funding, we will continue to scale the market for our technology and will grow national operating teams in at least 10 countries. There is enormous potential for our thermal storage technologies and products both under Sunamp and partner brands. Our order book grew 250-fold from £200,000 in March 2020 to £55 million by the end of the same year, mainly due to large scale, multi-year OEM and distribution partnerships in Asia, the UK and Europe. There are many exciting opportunities in Sunamp’s pipeline, including some that will see us become firmly established in commercial, industrial and automotive markets as well.”

Eilidh Mactaggart, CEO of Scottish National Investment Bank, said "This innovative Scottish business has developed technology which can make a significant positive impact on domestic and commercial heat provision.

“Sunamp’s thermal energy storage products have the potential to make a significant positive impact on domestic and commercial heat generation and energy efficiency. It is reflective of the quality of Scotland’s research institutions that this technology has been developed in collaboration with the University of Edinburgh and is now being exported internationally. It is an exciting time for the Bank to be supporting the team at Sunamp as they seek to further expand both domestically and internationally.”

For Scottish National Investment Bank media enquiries contact:

Graham McKendry

3x1 Group

07931 382 270


For Sunamp media enquiries contact:

Maggie Wright

07801 710360



Notes to editors        

About Sunamp

Sunamp designs and manufactures space-saving thermal storage products using its patented high energy density phase change material technology, which captures energy from almost any energy source and releases it for heating, cooling and hot water on demand, cutting energy consumption and carbon emissions.

Sunamp heat batteries are used for heating and cooling across a wide range of temperatures, and for a wide range of residential and industrial applications. The company’s range of products for the residential market replaces bulky hot water cylinders with space-saving heat batteries.

Compact, A+ rated and scalable, Sunamp’s heat batteries allow more renewable energy to be used both behind the meter and in the electricity grid by helping to absorb peaks of renewable energy generation, deal with intermittency and reduce curtailment.

Sunamp expects to expand in China, Korea, Germany, Netherlands, France, Ireland, Chile, Canada and the USA. Recruitment is underway for roles in sales, support and manufacturing.

The company previously closed off £4.9m ($6.7m) series A led by Aurus Capital, one of the largest venture capital firms in Latin America with a specialisation in Industrial Technologies investments. Scottish Enterprise and existing private investors were key participants.


The Scottish National Investment Bank is Scotland’s first development investment bank, wholly owned by Scottish Ministers on behalf of the people of Scotland.

The Bank is an impact investor, focussed on delivering both commercial returns and mission impacts with its investments.  The Bank is a PLC and operationally independent from the Scottish government.

The Bank invests in businesses and projects connected to Scotland to deliver long term, patient debt or equity investment where the private market is failing to provide the support businesses and projects require to grow.   

The Bank’s missions are:

  • Supporting Scotland’s transition to net zero
  • Building communities and promoting equality
  • Harnessing innovation to enable our people to flourish

The Scottish Government has committed to capitalising the Bank with £2bn in its first 10 years. Over time as the Bank’s initial investments are repaid, the Bank will reinvest those funds in businesses and projects creating a perpetual investment fund to support the Scottish economy in the long term.

The Bank was established in November 2020 and is led by Chief Executive, Eilidh Mactaggart.


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