During the week that more than one million households were asked to cut their energy, switch off their appliances and go dark for one hour or so, there was a home in the Hampshire hills which does not need to save energy, because it “uses the grid as a battery”.

A five-bedroom, five-bathroom eco-home, Warrenside Farm, in the Hampshire hills may look like an average country pile, but through clever engineering, it actually generates more energy than it uses.

A ground source heat pump, tripled glazed windows, special insulation, and mechanical ventilation systems are some of the technologies deployed to maximise the home’s energy efficiency potential.

ELN spoke to Martin Evans, an engineer who is the Director at the Malthouse Consultancy who explained how his “carbon negative” home operates.

“We are not off-grid, we use the grid in effect as a battery, when we have a sunny day, we generate a lot more energy than we use. So we export that to the grid and if it’s a very cold, overcast day, then we will import from the grid, but what we aim for is a true net zero or net negative across a year, to make sure that the total we import is less than the total that we export. So, we export more energy than we import in total across the year.”

Mr Evans says that his “green” home helps him save a lot of money on fuel costs – he said: “I did a calculation to look at what would be spending on energy if we were back before we converted the house – the total running costs for the diesel equivalent and LPG based heating would be around £24,000 a year at today’s costs.

“That’s for all our travel as well, that’s covering 30,000 miles a year. So the cost for us now is something like £4,000 a year or slightly less.”

Click the podcast to listen to the full interview.