The boss of a Norfolk firm at the vanguard of the green economy hopes that its growth can pick up pace under the new Conservative government.

Finn Geotherm UK, based in Deopham Road, Attleborough, has seen a six-fold expansion of its heat pump installation business over the past five years.

And Guy Ransom, commercial director of a firm that has put itself forward for the EDP's Green 100 which seeks to champion businesses with eco-friendly credentials, believes that the appointment of Amber Rudd as the new energy and climate change secretary is a signal of David Cameron's commitment to the climate change agenda.

Green campaigners had feared the appointment of a climate change sceptic but Rudd has said climate science is 'compelling' and is described by one government insider as 'really green and no-nonsense'.

Mr Ransom, a founding director of Finn Geotherm in 2006, said: 'It is very positive in our view. We did not want any knee-jerk changes under the new government.'

In the five years from 2009 to 2014, the company he runs with fellow director David Alston confounded the economic downturn by growing turnover from £275,000 to £1.6m and increasing its staff from three to 15.

And Mr Ransom believes the market they have reached so far for ground source heat pumps, which use pipes buried underground to extract heat from the earth, and air source heat pumps, which absorb heat from the outside air, is still just the tip of the iceberg.

Finn Geotherm was recently commended as runner-up in national awards for its work installing an 80kw ground source heat pump at the Royal School for Deaf Children in Margate and Mr Ransom said there was a strong economic argument for many schools across the country to switch their energy systems.

He said: 'The case is most compelling for those hundreds of schools who are off the main gas grid and have large playing fields where a ground source collector loop can be installed,'

He said the cost of the Margate school installation was £120,000 but the payback on that - in terms of energy savings and government renewable heat incentive payments - could come in as little as five or six years.

'The government payments continue for 20 years on commercial installations and a heat pump can typically give 30 years of service,' he said.

Mr Ransom, who is proud that Brendan Scott, 20, one of their two apprentices, was recently voted apprentice of the year at City College Norwich, said some 'exceptional commercial projects were in the offing', including the installation of a ground source heat pump at a large local school about to be built and a £500,000 contract with a grain research company in Suffolk for a heating system in a huge glass house.

The company has just invested £50,000-plus in doubling its office space – 'of course heating it with a Lampoassa ground source heat pump system' – and brought in a new fleet of five VW Transporter vans for its engineers.

'In the next six months we will be looking to take on another two engineers and two sales people,' he said.

To enter the Green 100 go to edp24.co.uk/business and click on the Green 100 logo.

Key criteria: Businesses or organisations which have demonstrated innovation or growth through the adoption of sustainable procedures, products or services; businesses or organisations working with partner companies to ensure the adoption of green/sustainable processes into their supply chain; businesses working in the 'green economy' producing innovative products and services to help customers become more sustainable.