• April 9, 2014 - Domestic Renewable Heat Incentive Released - Solar Thermal has got the great government funding through the Domestic RHI which it deserves! Solartwin Solar Thermal panels have just become not only a cost cutting and very green option to heat your water but now you will receive additional... More →
  • November 6, 2013 - Notice to Solartwin customers - Letter's from Stenfield & Co - A number of Solar Twin Ltd customers have been in touch this week to query a letter they have received from legal firm Stenfield & Co. - The content relates to Solar Twin Ltd's liquidation, and claims that customers "undoubtedly paid more than... More →
  • July 12, 2013 - Renewable Heat Incentive Updated - Solar Thermal to have Heavy Support - The Government have today released the Renewable Heat Incentive: The first step to transforming the way we heat our homes. If you are looking to buy a SolarTwin System contact Genfit. "the scheme will be open to anyone in these groups who installed... More →
  • May 27, 2013 - DECC announce they are doubling the RHPP grant for solar thermal from £300 to £600 - Solar Thermal Panels Receive Huge Renewable Heat Premium Payment - Solar Thermal has received a huge boost, it's a great time to buy a Solartwin Product. - Greg Barker tweeted about the scheme - - Big uplift for #RHPP Vouchers to put a shot in the... More →
  • February 14, 2013 - Solartwin DIY reviews - SolarTwin Reviews from Reviewcentre - "Review Centre is a community of real people, just like you, sharing their product and service experiences. - Our community of reviewers are a passionate bunch who want to help you discover what's right for... More →
  • January 17, 2013 - Crackdown on aggresive solar selling - YouGen, a leading consumer body serving the renewable and energy efficiency sectors, is calling for a change in the law after a review by the Office of Fair Trading revealed unscrupulous selling tactics by solar and other energy efficiency... More →

Obituary: Kerr MacGregor, Scottish Polymath, Inventor of Solartwin.

Filed under: Latest News

News: 25 March 2011. Britain’s leading solar heating product inventor, Archibald William Kerr MacGregor, 70, of Temple Village, Midlothian, Scotland, died suddenly on Tuesday this week while involved in promoting solar energy.

Kerr MacGregor invented Solartwin (initially known as Flex-sol) , a simple, freeze tolerant, solar water heating system. Over 5000 Solartwin installations are in place across the world, saving nearly 2000 tonnes of CO2 emissions per year thanks to Kerr. But that’s not all…

Seven other inventions by Kerr Macgregor include:

  • Solar Clip Fins – widely used in DIY construction of solar collectors across the world
  • the Thermoscreen, an efficient electric infrared heater, creating pockets of low cost warmth to sit and work, within otherwise cold buildings
  • Smart Solar Shades – for sunspaces in homes
  • Underground Heat Storage – for greenhouses so seedlings can get 2 weeks head start in growth in Spring
  • Low cost design large solar collectors – used in swimming pools in UK and Spain
  • Transpired Plate and Fabric solar collectors – for applications including wood drying
  • Solar Thermal Slates – now used in hundreds of Scottish “Hard to Heat” homes to heat air and control damp and related asthma problems at low cost.

Born in Scotland, his early childhood spent in India, then sent to a spartan boarding school in UK while young, Kerr’s Scottish blood was infused with intellectual and physical wanderlusts which were both irrepressible. Much later in his life, astride a specially adapted solar bicycle, Kerr bicycled from the East coast of Scotland to the West coast, and then back. As with Victorian boat trips to India before his birth, his side-mounted, moveable solar electric panels “travelled posh” (port outbound starboard home) – this time in order to face (ie not avoid) the sunny south – on both legs of his journey. Unlike the Victorians, however, it was quietly implicit in Kerr’s life that he had no truck with the notion, one which still pervades some policy thinking today, that nature is a gift to humanity – who, in turn, can do what they like with it. Instead, Kerr’s approach was benign and more focussed on enjoying nature, and, as a creative engineer, on developing ways of harvesting its surplus energy resources as unobtrusively as possible.

Concerned about the many problems related to fossil fuels, but aware of the context that they had enabled the industrial revolution to take off, he saw them as precious and not to be wasted or over-used. He acknowledged the supremacy of liquid fossil fuels as convenient, concentrated, highly portable forms of power, particularly for use in transport. Keen to examine, and support, if they passed his rigorous evaluations, other people’s alternative visions, Kerr was enthusiastic about the potential of compressed air powered vehicles, some of which are now being developed in France and India. He told me that India, as a populous and rapidly developing country, was a perfect candidate for bypassing fossil fuel transport – by the development of, instead, a national compressed air grid, kept topped up by wind-compressor turbines and other forms of renewable of energy. Kerr’s vision was that every lamp post would have a low cost air compressor turbine on top. These would all be connected to a high pressure grid/reservoir pipes below. Whenever you get home, or stop for a cuppa – you just top up your vehicle with clean air!

Transport, in all its forms, fascinated Kerr. A keen motorcyclist and collector of forms of two wheeled transport, some years later, in his 60’s Kerr motorcycled around Portugal, where he researched the early Knights Templar, who were closely connected with his village. He also motorcycled across several Indian states, re-visiting the old haunts, tastes and scents of his youth, while thinking about India’s air-grid potential. Right up to his last day, running it on biodiesel, when he could, Kerr also drove a four wheeled solar display van called “Solar One”, which introduced, in a hands-on way, the potential of solar technology to schools, festivals and exhibitions. It was covered in, and crammed full of solar gadgets and games such as a solar car racetrack. Designed by Kerr, it has solar underfloor heating and a concealed bunk. In this mobile explanation, Kerr would often stay away from home for a week or more, spreading the rationality of renewable energy to all who would sample his enthusiasm.

Returning from the Isle of Tiree, after such a promotional trip with Solar One, Kerr suddenly died.

Kerr’s life was often more experiential than concrete. Thinking, sitting by the fire stroking his cat, energy, travel, whisky, politics, campaigning, technology, making music, friends and family love: they all sustained the man I have known for over fifteen years. Kerr was immune to both high fashion and consumerism, with the exception of kilts, motorbikes, and the latest green energy gadgets.

Kerr was deep, emotional and multifaceted: a genuine polymath. Superficially, however, Kerr fitted many of the stereotypes of a cerebral boffin, not only because of his insatiable intellectual wanderlust, but also, sometimes, because of his appearance. While many aesthetic sensibilities were rooted in his soul, visual matters were rarely of much consequence to him, particularly when he was away from his caring family, or when continuously operating cerebrally. Then, stray oatcake crumbs might find company within his beard. Practical to the core, his glasses were sometimes lashed together with differently coloured bits of insulating tape.

Untouched by today’s modern superficiality, Kerr’s surfaces were only there to be looked beneath, if you chose to. Below was the irrepressible magic of logic. More than once, Kerr turned up at our Chester offices after four hours on the Edinburgh train, almost looking like he had slept rough, carrying two battered bags-for-life crammed with pencilled calculations and his latest sharp-edged prototypes, carefully cocooned in bubble wrap. Once, my colleagues, looking dubiously at the entry video at the front door latch, asked me to confirm that the person who claimed to have an appointment with me really had one, before they pressed the button to let him in. Together, our hours burnt away in a colourful riot of travel anecdotes, technical ideas, what-ifs, sky-pie business plans, patent application drafts, interspersed with local walks and tours to as many English and Welsh technical museums or industrial heritage sites as we could fit in.

At the end of some brainstorming sessions we sometimes just ended up with far too much more follow-up work: with too many lists and questions for a whole university department to ever answer. Zonked, we, led by Kerr, would usually look at the problem again. On the winning days, well fitting ideas and solutions would cascade with casual ease. Yes! We could distill a brand new product that really would fly – and fly commercially (because that’s the acid test) as well as just intellectually.

For the green consumer, Kerr’s leading commercially successful invention is probably Solartwin: a big, flat, thirty square foot, award winning solar water heating panel which is freezable, unlike almost all other solar panels in the world. By putting water inside his panel, his first vital improvement, Kerr dispensed with antifreeze, which is about six times more viscous. The easier circulation of water, instead of a rather unstable chemical gloop, meant that a miniature, and highly energy efficient pump could be used, instead of a large clunker. We ended up with a pump so small that it could fit in your pocket – and so efficient that it could powered by just a few watts of sunlight via a solar electric panel which itself is smaller than a sheet of A4 paper. Of course, solar powering Kerr’s new solar heating system’s pump, got rid of the need for power generation at electric power stations, along with all their dirty emissions. Putting a figure on this dirt, comparative DTI field trials soon showed that the CO2 savings of typical old solar heating panels are negated by 20% by using mains pumps. Kerr has already ditched them. As a further step on the innovation cascade, we also knew that we could fit Kerr’s simple new solar panels to existing (rather than expensive replacement) hot water stores, also reducing waste. This innovation meant we could install in less than a day – instead of two days, which is what old solar usually needs – an (arguably) welcome productivity advance – on top its safety environmental, cost saving and energy efficiency advances.

Kerr’s original, lateral thinking has just about sustained our family and up to 15 of my colleagues’ families for the past twelve years. And it has saved the planet far better than most solar panels – because of its ultra-light carbon footprint. Thank you, Kerr, for your unique brain’s connectivity. This simple freeze tolerance feature made his panel far greener, safer, simpler and easier to install than the rest. Simplicity and technical elegance typified Kerr’s approach, but I still don’t know how he spotted the conceptual jigsaw parts to fit together in the first place. “Redesign right from scratch” is what Kerr often did, and in doing so, he developed this “disruptive technology” which has shaken UK’s self-serving solar industry so deep to its roots, that one UK trade association still boycotts it, seemingly because it is viewed by some solar installers as a Spinning Jenny.

The clich that “new products are 10% innovation and 90% perspiration” is true. Even if that 10% is one of the scarcest of global resources, much of the initial perspiration can be as a result of long, lonely, mountainous slogs. Over two years, one of Kerr’s doctorate students, at Napier University, Tom Grassie patiently trialled and mathematically modelled his invention. Tom’s complex spreadsheets enabled us to find, among a wasteland of no-go areas (where the concept simply would not work properly) a “hyperdimensional sweet spot” for our final production models, so that the proposed new product’s flow rates, materials, coatings, dimensions and manufacture specifications could nearly all be predicted or calculated with confidence. With only one significant upgrade, that of more complex electronic controls (also 100% solar powered) Solartwin is essentially the same product as Tom Grassie’s model simulated that it should be, twelve years ago.

Of course, commercially, nobody should ever have taken on Kerr’s amazing patent. Except, perhaps, to buy it up and bury it, or to overprice it so it cannot be adopted, or “put it on hold, in reserve”, as is rumoured to be the fate of too many of the world’s best technological brainwaves. The power which is delivered by Government to existing industry incumbents encourages large but vulnerable competitors, for years, to quietly, ruthlessly and systematically wreck the potential markets for game-changing, but minority innovations like Kerr’s. “Define the official scope of solar heating technology so that Kerr’s invention falls just outside” is still the name of one game. Another trick is: “Define historical solar as the best practice. Now define best practice as the only permissible approach, or at least the only technology which allowed to get state subsidy.” One senior industry player, seemingly irritated by our persistence, once told us to shut up or face “consequences”. The consequences of Kerr’s innovation being inherently superior seem to include omissions and misleading phrases thrown into UK’s cross-connected regulatory pot of: solar installer training materials, building regulations, energy saving best practice guides, standards and grants requirements. A clubby strangulation of “industry consensus” has repeatedly trumped good science contaminating, squeezing, even at times totally closing parts of UK’s solar heating market for Kerr’s innovation. Great news for the sports car buying hobbies of the clever lawyers we have repeatedly had to engage in order to seek a less tilted playing field.

Takeup of Kerr’s invention by solar consumers would have been many multiples of what is is today, if it were not for the cultural corruption which is inherent in today’s drift towards what is sometimes celebrated as “industry self-regulation” which has facilitated (and sometimes celebrated) the repeated mugging of his unique product’s market (and now of Kerr heirs). Kerr usually responded predictably to my expressions of frustration about the latest regulatory freeze-ups: first with bewilderment at how a supposedly ethical industry could do such things, then with expressions of surprise at my not being able to stop the rot, followed reflectively by asking “what can I do?” and finally with a flurry of polite letter-writing to those concerned.

Kerr MacGregor always seemed comfortable with his broad creativity. Although he was modest, he was also fully aware of the exceptionality of his talents: once he ventured to imply that his inventions numbered among Europe’s foremost solar inventions, ranking alongside evacuated tube solar collectors. I told him he was stating the obvious. But Kerr himself never claimed to be a leading inventor – he referred, rather distantly, to his innovations. He did not permit his gifts to distance himself from people. Instead, he was generous with another talent – that of communicating technical complexities clearly and simply – very widely. For three decades, working an academic as well as an inventor, Kerr inspired energy engineering students across several Scottish Universities, including Napier and Glasgow. Vocal against the sidelining of tertiary science and engineering teaching, and at the cost-saving closure of engineering labs where he used to teach, Kerr presciently deplored the noughties’ fetishisation of service and financial skills, preferring to see manufacture and technical innovations as more important. Patient in his explanations with the likes of us who were, yes, slower than him, practical, solutions-focussed and a careful, critical listener, I shared Kerr’s disappointment at him being rejected by VSO for a posting in Africa because he was “too opinionated”. Some statistical personality assessment process may need re-calibration.

The British Isles have not just lost its top solar heating inventor. Scotland has also lost a passionately rational nationalist, who was, for many years, an energy policy adviser to the Scottish National Party. Kerr’s persistent logicality and courteous lobbying is partly responsible for Scotland’s green energy policies being many years ahead of those which exist south of the border. Kerr’s nationalism, although all-pervasive, was also un-invasive, courteous and intensely cultural. On numerous summer sailing trips around Scotland, Kerr and his friends apparently planned their voyages by putting the winds in second place to their route’s product sampling potential – at island distilleries. Malt whiskies were an evening indulgence he shared with guests to his family’s traditional stone built, partly solar heated home which was populated by more harps than I have ever seen. “Living in this house is like living in heaven” he once said to me, his gentle voice rejoicing in their music.

Bagpipes, both conventional Scottish pipes and his portable pocket-sized bagless solar powered pipes were Kerr’s chosen musical instrument at most get-togethers. At international solar conferences, after enduring numerous detailed Powerpoints (explainalised in EuroEngrish) Kerr, wearing his kilt, would stride up to the podium, thank his hosts with a broad smile, and finally pipe the Gay Gordons. [A video of clad his prototype in tartan. Scotland has lost a rational green nationalist. The world has lost an inventive polymath. I have lost a critical friend. But Kerr MacGregor’s environmental gifts to the world live on.

MacGREGOR KERR (Temple Village). Suddenly, on Tuesday, 22nd March, 2011, Kerr, dear husband and friend of Anabel, much loved and loving father of Kirsty, Eoghann, Ellen and Colin and proud grandad of Sorley and Alasdair. Following a Private Committal, Memorial Service on Friday, 1st April, at Temple Village Hall, Midlothian, Scotland, at 2pm, to which all are welcome. Family flowers only, please.

Our thoughts are for Kerr’s family.

From Barry, the Johnston family and everyone at Solartwin. 25 March 2011

(No copyright whatever applies to this obituary. Please feel free to reproduce and improve on it


Written and published by -
Genfit - 0344 567 9032

For speed, and for the sake of the environment, Solartwin offer feasibility checks and fixed price solar quotes by phone.
Unique in the world, Solartwin's phone survey now also uses online aerial photographs of your roof in most urban areas!

Unlike most solar surveys, our instant surveys and quotes are completely free and with no obligation.
Click here to request a survey

Or Call us on

0344 567 9032

Domestic Renewable Heat Incentive Released

Solar Thermal has got the great government funding through the Domestic RHI which it deserves! Solartwin Solar Thermal panels have just become not only a cost cutting and very green option to heat your water but now you will receive additional funding too! The Domestic RHI rates – Released April 2014 Ofgem have produced a […]

Read More | Archives

Notice to Solartwin customers – Letter’s from Stenfield & Co

A number of Solar Twin Ltd customers have been in touch this week to query a letter they have received from legal firm Stenfield & Co. The content relates to Solar Twin Ltd’s liquidation, and claims that customers “undoubtedly paid more than you should have and it is highly likely that you will have been […]

Read More | Archives

Renewable Heat Incentive Updated – Solar Thermal to have Heavy Support

The Government have today released the Renewable Heat Incentive: The first step to transforming the way we heat our homes. If you are looking to buy a SolarTwin System contact Genfit. “the scheme will be open to anyone in these groups who installed an eligible technology since 15th July 2009” so if you have a […]

Read More | Archives

DECC announce they are doubling the RHPP grant for solar thermal from £300 to £600

Solar Thermal Panels Receive Huge Renewable Heat Premium Payment Solar Thermal has received a huge boost, it’s a great time to buy a Solartwin Product. Greg Barker tweeted about the scheme – Big uplift for #RHPP Vouchers to put a shot in the arm of the market ahead of full Domestic #RHI tinyurl.com/ktxz3o2 — Greg […]

Read More | Archives

Solartwin DIY reviews

SolarTwin Reviews from Reviewcentre “Review Centre is a community of real people, just like you, sharing their product and service experiences. Our community of reviewers are a passionate bunch who want to help you discover what’s right for you.” (Review Centre) We are well rated on review centre, this shows the excellent product quality of […]

Read More | Archives


or jump to...