Renewable energy firm’s surge in demand

Demand for sustainable energy to power homes and cars has seen a business established on a kitchen table evolve into a growing team based in a state-of-the-art showroom.

RNS partner Karen Lyth with Graham

Demand for sustainable energy to power homes and cars has seen a business established on a kitchen table evolve into a growing team based in a state-of-the-art showroom.

The Heat Source provides the latest advances in green technology at its Hillcrest Park base in Caistor, with Government MCS Accreditation to install products from the likes of American car giant Tesla and Stallingborough-based renewables innovator Myenergi.

It was very different 15 years ago when husband and wife team Clare and Grahame Harriman linked up with RNS Chartered Accountants at its Brigg office.

Clare said: “It was about Grahame's vision. He could see what was going to happen regarding the transition to clean energy solutions many years ago.

“We had two very young children and little money to spare. Grahame took the opportunity to retrain as a plumber and electrician at night school whilst holding down a full-time job. This was not easy!

“Once qualified, he took the leap of becoming self-employed, initially working on fossil fuel boilers.

“However, he could see the clean energy potential of electric air source heat pumps and why the technology had been embraced in Scandinavia and Europe.”

The game changer was achieving MCS (Micro-Certification Scheme) Accreditation from OfGem 12 years ago.

“We were one of the first companies in the country to gain this highly sought after quality standard,” said Clare.

“We are audited every year to ensure the highest standards of installation for renewable technologies are maintained.

“This accreditation enables our business to install solar PV panels, Tesla Powerwall batteries, Mitsubishi air source heat pumps, under floor heating, biomass boilers and Myenergi EV chargepoints.

“The business grew from our kitchen table to our converted garage, but it wasn't a suitable place to bring prospective clients.

“We are now in a modern, professional setting which also helps us personally to separate work from home.

“I have seen the graft that Grahame has put in. Even now, there is no room for complacency and he works incredibly hard.”

They met RNS partner Karen Lyth 15 years ago, beginning their company as a sole trader before switching to a limited company.

“We work closely with Karen, Chris, Amy and the team meeting every two or three months,” said Clare.

“The numbers need careful management and meeting face-to-face enables us to chat about where we are at.

“The relationship works really well and having that personal support is important to us. They keep track of the figures and we value their input massively.”

“We have unprecedented demand on our services,” he said. “It has really gone through the roof over the last three years and particularly during lockdown.

“Awareness of the climate crisis and net-zero targets along with rising energy costs have accelerated the transition to clean energy solutions.”

The invasion of Ukraine by Russia and the resulting surge in energy prices has further focused people's minds on becoming more self sufficient with energy generation and not being dependent on gas to heat their homes.

“We are finally seeing awareness of what can be achieved and traction in the market,” said Grahame.

Battery storage means that energy generated by solar panels can be stored and used by households when needed, for instance at night. Batteries can even be charged overnight on a Time-of-Use electricity tariff.

The issue is the shortage of qualified engineers to fit the technology.

Grahame and Clare are working with North Lindsey College in Scunthorpe and Grimsby Institute, creating apprenticeships and encouraging younger people to join the profession.

He said: “For young people, this is a growing industry from which a decent living can be made.

“It is specialised. We pride ourselves on the quality of our work. We have a really good, tight-knit team and are managing the growth and customers' expectations.

“The showroom demonstrates the variety of products and how they can be integrated to create the ultimate low carbon home and business,” said Grahame.

RNS partner Karen Lyth congratulated the couple.

“The business has made huge strides since being established as a sole trader all those years ago,” said Karen.

“Grahame was ahead of his time, seeing the opportunities offered by a low carbon future.

“It has not been easy and the business has needed to adapt to changes in Government policy.

“He and Clare have worked so hard to get the business where it is today and we're proud to provide support.”

For business support, contact RNS Chartered Accountants on Brigg 01652 655111 or email

To find out more about The Heat Source, go to

Grahame at The Heat Source’s showroom in Caistor
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