‘I did these things to my house and now I have zero energy bills’

When Phil and Jackie Coates look at their electricity bills they have a different reaction from most. Because, unlike most people, the Coates home actually makes money. It even charges their electric vehicle for free. Their two sets of solar panels generated twice as much electricity as the couple consumed in 2024. They export the excess power to the grid and are paid for it.

They went down this route to reduce their energy bills and for environmental reasons, as, thanks to the solar panels and a heat pump, they no longer need gas – a fossil fuel – in their house.

Mr Coates said said in terms of home energy he and his wife were living a “zero carbon” life “but without living in a mud hut and eating beans”. He said: “Looking back I would not have done anything differently.”

The number of people installing heat pumps rose by just over 50% in the UK last year compared to 2023, according to a group called the Heat Pump Association, but that will need to increase sixfold to meet a Government target of 600,000 per year by 2028 as part of a legally-binding push to reach net zero by 2050. If net zero is achieved it will mean the UK is no longer adding to the greenhouse gas emissions which heat the planet. Never miss a Swansea story by signing up to our newsletter here

Just switching energy tariffs takes a bit of research, so switching your home’s physical energy systems really does require homework as well as money for upfront costs.

But you don’t have to do it all at once, and experts say the cost of solar panels, heat pumps and batteries to store electricity is coming down and that grant and loan schemes are available. They add that reducing the price we all pay for electricity would further incentivise householders to consider following the likes of Mr and Mrs Coates.

The couple bought their house in Mumbles in 1992 and added a set of solar panels in 2010. South-facing roofs are preferable as they capture sunshine for longer but Mr and Mrs Coates’ roof faces west and east. Their first solar installation was on the west side, costing just over £15,000. It was a lot of money but they benefited from a generous feed-in-tariff which guaranteed them a certain price for the electricity they generated and exported to the grid for 25 years.

This meant they recouped the upfront cost after around eight years and then reinvested it into the east-facing panels in 2022, which cost around £13,000. The replacement subsidy for excess electricity exported to the grid is now less generous, but the more modern panels they installed second time round deliver far more bang for the buck than the first.

A further addition in 2022 was the heat pump, which replaced an old gas central heating boiler. Heat pumps use electricity to draw warmth from the air outside – even in winter – boost it and then feed it into the hot water system, warming a home’s radiators. You don’t get the rapid burst of heat that gas-powered combi boilers provide, and you do need a hot water cylinder to store the warm water.

The Coates were fortunate that a UK Government grant will pay for their heat pump and installation costs over a seven-year period. The cost came to just under £9,700. Heat pumps come in different sizes and large radiators and wide-bore hot water pipes ensure optimal results.

Mr Coates decided to only replace one radiator, in the hall. “Our radiators are large but not hugely efficient,” he said. “The new one in the hallway does work better, but new radiators throughout the house would have cost an extra £2,000.” They also retained their existing pipework.

Mr Coates, 64, stressed that improving a home’s insulation was a key step to reducing heat loss. “It’s something everybody should do,” he said. “It’s a no-brainer. It saves money and saves carbon emissions.” The Coates had their old, poor-performing cavity wall insulation replaced and upgraded their loft insulation themselves, costing a total of around £2,000.

Their well-researched take-up of green technology is different to simply replacing an ageing gas combi boiler, as most householders do. If you’re struggling to meet your monthly mortgage bill or thinking of moving home, investing in solar panels or a heat pump might not be high on your agenda.

There’s also the question of choosing an electricity tariff which incentivises you, for example, to charge your electric vehicle and power up your heat pump at night in preparation for the following day, because the night-time unit price of electricity is much lower than the daytime price.

Installing home energy batteries can smooth out these price differentials as you can charge it up when electricity costs are low and draw from it when they’re high. But they too have an upfront cost – Mr Coates said around £6,000 in his case – and he is doing without one. He reckoned investing in more solar panels would, in his case, be a better use of that money.

As things stand the Coates make a return every year on their investment as well as powering their home and running their electric car, which does 9,000-odd miles per year, for free. This is mainly due to the generous feed-in-tariff from their first set of solar panels and also the way they’ve adjusted their behaviour.

Reflecting on the environmental benefits, Mr Coates said: “We’ve got climate change happening, and we’ve got one planet. I think it’s incumbent on all of us to consider our way of life to reduce our footprint. It all adds up.”

Ashley Hale, managing director of Swansea firm Hale Heating and Renewables, said his family-run company had more demand for solar panels and batteries than heat pumps at present. Asked what advice he would give to householders considering new installations, Mr Hale said: “Research companies and get them round to your home. Make sure they check your roof, the tiles, the loft space. It’s all about the right design. You design the system to maximise savings.”

He added: “The technology has improved so much. Our solar panels and equipment are mostly from China. It’s fantastic quality. Our panels have a 30-year product warranty and a 25-year performance warranty. I would love it if they were from a British company, but it’s the cost of manufacturing.”

Mr Hale said batteries were in his view a “game-changer”, allowing householders to build up a store of electricity and draw from it at times of their choosing. The former Army engineer said upgrading home insulation was “massive” when it came to heat pumps and that space was needed internally for a water tank.

Mr Hale also advocated better education for the public on this subject, and said his company would be opening a new renewables centre in Cwmdu Industrial Estate, Cwmdu, where people could find out more about home energy technology.

A larger-scale housing energy project, called homes as power stations, is being rolled out as part of the city deal for the Swansea Bay City Region. The target is to retrofit 7,000 existing properties and deliver 3,300 new ones in Swansea, Neath Port Talbot, Carmarthenshire and Pembrokeshire so that they’re effectively mini-power stations.

“It’s creating cleaner, greener and more energy-efficient homes,” said homes as power stations project manager Oonagh Gavigan. It was a complex subject, she said, as most properties were different as were householders’ needs. “Technology can be fantastic or a massive failure,” she said. “Getting the ingredients right is something of a task.”

The project is helping housing associations and councils decarbonise their housing stock. Two demonstration homes with differing installations have been created in Margam by housing association Tai Tarian, with the Cardiff University’s Welsh School of Architecture undertaking pre- and post-installation monitoring.

Ms Gavigan said people living in homes as power stations needed to use them correctly. “If you get that right you should have very, very low or nearly zero bills,” she said. Ms Gavigan agreed that technology had improved significantly and that costs were coming down. Importantly, she said mortgage companies and lenders were starting to see the benefits of this technology.

Her colleague Alec Thomas, the project’s supply chain lead, said there was a skills shortage in terms of maintenance as well as installation. “We need new people, and existing people,” he said. Both he and Ms Gavigan said they would consider installing solar panels and a battery in their homes at some point. “It is something I’m looking into at the moment,” said Ms Gavigan.

The UK Government runs a scheme offering loans to householders to make energy-saving improvements. There is also a £7,500 subsidy for homeowners and property landlords to upgrade existing boilers with heat pumps. The cost of these £7,500 grants comes from general taxation. The cost of the old, generous feed-in tariffs are funded through consumers’ energy bills.

There are also two schemes in Wales – Green Homes Wales, managed by the Development Bank of Wales, which provides advice, interest-free loans and access to grant funding, and Nest Warm Homes, which offers advice and also free energy-saving measures for eligible low-income households.

In Mumbles, Mrs Coates said she and her husband were more mindful to use electricity at night, for example heating the home’s water or running the washing machine, to make use of cheap tariffs. This same applied when it was sunny and the solar panels were operating at high output.

Asked if friends and neighbours were curious about what they’d installed, and what tips she would give, Mrs Coates said: “Go for it! Particularly consider fitting solar panels because they are ‘fit-and-forget’ and the payback period is quick.” She said she was pleased that her carbon footprint had reduced. “Collectively we can make a big difference,” she said. “The fact these measures save money is the icing on the cake.”