Meet the trailblazing eco renovator who pays ‘almost nothing’ for his energy bills

Paul Kershaw is pictured to the left with his electric vehicle on his driveway
Paul Kershaw is leading the way with green technology in his home (Image credit: Paul Kershaw)

When it comes to green living, Paul Kershaw has moved the eco bar to another level.

Not only has he retrofitted his 1960s home so it generates its own source of renewable energy, but he's also helping out by supplying his neighbours with local green energy too. The 51-year-old's timing couldn't be better either, with energy prices increasing to unprecedented levels.

Paul, who had no previous renovation experience, decided to redesign his mid-terrace home in Cambridge after experiencing an accident at work. The original idea was to adapt the house, which he purchased seven years ago, so he could live more practically with his elderly mother. But soon he realised he could do more than that.

First he bought an electric car and added an EV charger to his home as part of a
pioneering vehicle-to-grid trial. After this, he installed solar panels as part of another trial and went off grid with his gas supply by installing an air source heat pump as well as making other environmentally-friendly improvements.

Soon, Paul found he was generating so much solar power that he was not only able to feed his own home, but also supply his neighbours with green energy.

Significantly, this was all achieved on a limited budget (£100,000) and without Paul having a background in building or engineering.

Paul’s home is being celebrated as part of Open Eco Homes, running in Cambridge between 12 September and 18 October. To celebrate its launch, we spoke to Paul about how his ambitious project came together and to see if we could learn any good energy saving tips too.

How 'vehicle-to-grid' earned Paul cash back

I’m greening the neighbours’ houses because I’m putting that solar energy in locally, which is a great feeling.

Paul Kershaw

Paul’s journey towards a greener home began when he was given the opportunity to purchase his first electric vehicle. 

His disability meant he was based at home without needing to travel to work, so he joined a vehicle-to-grid trial with energy firm Ovo and software company Kaluza. 

The trial gave drivers the option when charging an electric car at home to discharge and sell surplus electricity from the vehicle batteries back to the electricity grid.

“I found out about the vehicle-to-grid trial for the EV and I thought ‘that’s the future’. The car is at home during peak periods, so it can be fully charged during the day and help balance the grid,” said Paul. 

When Paul charged his Nissan Leal during off-peak times, the Kaluza app calculated its energy requirements as well as how much he could sell back to the grid. By charging the car during off-peak times and selling power back to National Grid during peak times, Paul says he averaged a payment of £93 a month charging his car on the trial, but made £164 selling power. 

Since the initial vehicle-to-grid trial ended, Paul has since joined a vehicle-to-home trial. This means when his EV is plugged in, it absorbs solar power and stores it in the car battery. The EV battery then matches the load of the house when the sun isn't shining.

paul kershaw using the Kaluza app to export electricity to the local grid

Paul Kershaw uses the Kaluza app to export electricity to the local grid (Image credit: Paul Kershaw)

How solar panels reduced Paul's bills to £7.50

Then last year he joined a buy-in scheme for solar panels, and the combination of an electric vehicle and solar panels reduced Paul’s energy bills to “almost nothing”. He says he pays just £7.50 for electricity per month.

As for the days when there isn’t much sun, like in the winter, Paul’s vehicle is moved on to an EV tariff. This affords him four cheap hours of electricity at night. 

“You can fill up the car battery then and this reduces the bill. So in the high solar generation months, I’m using the bare minimum of energy from the grid."

Grants for electric cars up to £1,500 had been available towards the cost of an electric car before they were scrapped by the Department for Transport in June. 

How Paul supplies green energy to his neighbours

Paul puts his excess green energy to good use too. He sells any excess energy generated from his EV and solar panels back to the local grid. This means his neighbours are able to benefit by using local green solar energy rather than generic power that might not come from renewable sources.

“Any excess solar power I generate gets exported to the local electricity grid as part of the Smart Export Guarantee, so it feeds out to our neighbours’ houses before it goes anywhere else," Paul explains.

"I’m greening the neighbours’ houses because I’m putting that solar energy in locally, which is a great feeling.”

Solar panels installed onto the rear roof of Paul Kershaw's home

Paul's house with solar panels being installed to the rear (Image credit: Paul Kershaw)

Ditching gas and adapting to a heat pump

Paul was able to go off grid with his gas supply by ditching his old gas combi boiler and switching to a heat pump instead.

Paul says his success with the vehicle-to-grid trial and solar panel trial helped his mother agree to making further green improvements. Paul toured other eco homes online though the Open Eco Homes (which his own home is now a part of) showing him how to retrofit a home to improve its energy efficiency. He then hired an architect, and while the Covid pandemic shut down his plans temporarily, in December he was able to install an air source heat pump under the Renewable Heat Incentive (now closed for new applications), and never looked back.

“The difference in efficiency to our old combi boiler is huge. In December I monitored our electricity and gas usage, and when the temperature dropped to zero our combi boiler was at 100kwh that day. One week after the heat pump was installed, the temperature again dropped to freezing and the heat pump was at 30kwh."

Choosing not to retrofit underfloor heating

Paul replaced the radiators when installing the heat pump but opted not to install underfloor heating to save money. 

“As a source of heat, the heat pump is fantastic. The efficiency and economy comes from it running all the time, so you’re very comfortable throughout the day and night. It heats our home at a lower temperature so that means radiators don’t kick out fierce heat.”

Insulating his home and adding more sunlight

Earlier this year, Paul teamed up with a builder friend to complete the rest of his renovation. He is now in the midst of building an extension to let more downstairs light into the house, and adding external wall insulation. 

He has had spray foam insulation applied to the pitched roof along with internal skeiling insulation, and increased the insulation to the flat roof.

Discussing how easy it was to obtain planning permission, Paul said: “The planners whistled through these changes, most likely because it’s all extremely energy efficient.”

Paul Kershaw installing Recticel insulation

Paul has enhanced his home's airtightness and insulation to make it more thermally efficient (Image credit: Paul Kershaw)

Paul's motivation for energy efficiency

With energy prices at a high, there’s never been a better time to make your home more energy efficient and as Paul's house shows, doing so isn't just for new builds.

Paul's eco transformation of his terraced house, which was originally built in 1968, was all about energy efficiency. He was able to ditch gas from the grid by having solar panels. His cooker still runs on LPG but he plans to switch this over to all-electric soon too.

But Paul’s limited budget meant he had to compromise on certain things. He opted for a mechanical extract ventilation (MEV) systems, also know as demand control ventilation, rather than MVHR, which Paul says doesn't have as high installation or running costs. 

"The cost of ducting an MVHR system was prohibitive so I’m using demand control ventilation, which has a permanent extraction of wet air from wet rooms, and the the in-flow of fresh air is controlled. Compared to MVHR, you lose a bit of money initially in the heat you’re not recovering, but it pays off in the end."

Paul is also reusing double glazing and re-fitting windows to be airtight and more thermally efficient, rather than having new glazing installed. 

Paul is hosting an online tour of his home on 15th September, alternatively you can view the house in person on 15 October. Book your tour here.

Jack Woodfield
News Editor

Jack has worked in journalism for 11 years and is the News Editor for Homebuilding & Renovating, a role he has had since 2019. He strives to break the most relevant and beneficial stories for self builders, extenders and renovators, including the latest news on the construction materials shortage and hydrogen heating. In 2021 he appeared on BBC's The World at One to discuss the government's planning reforms. 


He enjoys testing new tools and gadgets, and having bought his first home in 2013, he has renovated every room and recently finished a garden renovation.