How Russell and Kate installed solar panels and a heat pump

When the couple moved into their four-bedroom detached house in Somerset, it had oil-fired central heating. Russell and Kate were both concerned about its impact on the environment.

“Climate change has been on my radar for a long time,” explains Russell, who is a physics graduate. “I couldn’t bear the idea of oil tankers turning up twice a year to fill a tank, and then all that going off into the atmosphere.”

When their oil boiler needed replacing in 2020, they decided to install an air source heat pump instead.

After they had approached local companies, Russell and Kate decided to expand their energy-saving ambitions.

“One of the chaps who came along was very good,” Russell remembers. “He said, ‘If you can afford it, you could have solar panels as well, because they’ll integrate with the heat pump.’”

Russell and Kate opted for an 11.2kW air source heat pump to keep their home warm. They also installed a 3.65kW solar panel system with 18 panels to generate electricity. They added a diverter too, which meant unused electricity from the solar panels could be channeled into the hot water system.

Some of the spare energy from the solar panels would be used for hot water or charging an electric vehicle (EV). As a result, they decided they didn’t need to install a home battery. They did opt for monitoring and metering for the heat pump to get updates and data on its energy use and generation.

For Russell and Kate, installing the heat pump involved some significant home renovations. They saw this as an opportunity to modernise their home and make further energy efficiency improvements.

They already had new windows fitted. “That improved the thermal insulation of the property and meant that we could have a smaller heat pump,” Russell explains.

Because heat pumps run on a lower temperature system than an oil boiler, they needed to install larger radiators that could provide more heat. “We’ve moved nearly all of the radiators to internal walls, so there’s much less heat loss out through the fabric of the building,” Russell explains. Because they also needed new pipework for the heat pump, they had the whole heating system refurbished.

The installation took a week, during which Russell and Kate were able to stay in their home. “They removed the old oil boiler, changed the plumbing, changed the radiators, fitted the heat pump and put a larger hot water tank in the airing cupboard,” Russell recalls.

The solar panels and diverter were then fitted in a couple of days.

The fully integrated nature of their system meant there were challenges with integrating the solar diverter with the heat pump’s optional monitoring and metering units. It took a few weeks to fully resolve the issue, but Russell says the electrician found a creative solution.

Now everything has been running well for several years, and they get the heat pump serviced once a year.

Russell says that both he and Kate feel their sustainable switch from oil boiler to heat pump has been a huge success.

Kate says the house feels warmer than before. Russell has calculated that the heat pump has reduced their CO₂ emissions compared to their old oil boiler by about 80%. The remaining 20% will reduce even further as the electricity grid decarbonises.

They’re more comfortable having the heating on now, too. “When it was oil, we didn’t like to have it on so much, because we knew all that carbon was going into the atmosphere,” says Russell.

To make things even better, the system is totally automated. “There’s never even an issue of having to turn on the heating in the autumn, because if the house gets colder, the heat pump just comes on automatically.”

Russell and Kate received some funding towards this project from the Renewable Heat Incentive, which has since been replaced with the Boiler Upgrade Scheme.

Over time, they’re making their costs back. “The heat pump is certainly costing us less to run than an oil boiler and all those oil deliveries,” says Russell. “It’s hard to quantify that exactly, but it is quite a significant drop.”

The 18 solar panels generate about 4,500kWh of electricity a year. “We manage to use around 3,000kWh of this output. This saves us in the region of £750 per year, which reduces the cost of running our heat pump and our car charging,” Russell says.

Any solar energy they can’t use is sent to the grid for someone else to use. They’re paid for this exported energy through a Smart Export Guarantee tariff. When they need extra electricity to charge their EV they use a low cost overnight tariff.

To anyone thinking about doing the same thing, Russell says it’s important to know the following.

• Even when it’s frosty outside, heat pumps can still keep your home warm and cosy.
• Heat pumps aren’t necessarily more expensive to run than oil or gas boilers and can be cheaper. Some energy companies now have heat pump tariffs too.
• You don’t need underfloor heating with a heat pump, but you might need larger radiators and some new pipework.
• Older houses can have heat pumps installed, but it’s always a good idea to insulate your property as much as you can, whatever form of heating you have.
• You don’t have to have a south-facing roof for solar panels. Russell says his east and west facing solar panels combined work very well, spreading out the generation through the day.

The couple plan to move to a smaller house one day. Would they make the same changes all over again? Russell says, “we would do it again, for sure.”

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