Case study: Solar PV, solar thermal and heat pump system replaces gas central heating

Installer looks at how a family home in Wiltshire has made the move from a gas central heating system to a renewable solution.

In July, a Grant renewable heating system was installed for a detached, four bedroom house in Wiltshire. Alongside the new heating system, which has replaced the gas boiler previously heating the home, the family have also installed a solar PV system to provide their electricity. Using a local G1 Installer, Howard Croker & Sons, this home is having its heating, hot water and electricity requirements met by renewable energy, helping the family to be more sustainable and reduce their energy bills.

The property has been the home of Michelle and Nick Lancaster and their son Reece for twelve years. During this time, the family has made a number of alterations and adaptions to the property to suit the requirements of Reece, who was disabled from birth and requires 24/7 care. A wide range of medical equipment is installed, including a lift to take Reece upstairs and downstairs, a hoist to help him in and out of bed, monitoring equipment and a hydrotherapy pool for Reece to exercise in, and all this equipment contributed to the household’s incredibly high energy bills.

“Our bills were astronomical,” explained Michelle. “Our energy costs in one month would be the equivalent of what most families would spend in a year so we really needed an alternative solution to both our heating and hot water needs and our electricity usage.”

One of the first upgrades they made was the installation of a solar PV system which is using the sun’s energy to create electricity for the home. Due to the size of the system installed, the new solar PV panels create an oversupply during the day so the family are hoping to later install battery storage so that this renewable electricity can be used at night as well. The solar PV fulfills their electricity demand which has significantly reduced their monthly bills.

“We were keen to futureproof the home for Reece even further,” continued Nick. “The solar PV addressed our electricity usage but we also wanted our heating and hot water provided in a more cost-effective, sustainable way hence our research led us to heat pumps.”

To learn more about air source heat pumps and whether this technology would be suitable for their home, the Lancaster family turned to their neighbour and local heating company, Howard Croker & Sons. After carrying out a full heat loss calculation on the property, Dave Croker specified a renewable heating system that would fulfil both their heating and hot water demand. The system recommended and later installed included an Aerona³ 17kW air source heat pump, a Grant Solar Thermal 2-collector on-roof system, a 300ltr Quick Recovery Twin Coil Cylinder, a Grant Low-Loss Header and a Mag One filter.

“We have been installing Grant products for many years,” comments Dave. “In recent years, we have been fitting more and more renewable heating solutions for our customers and when Michelle and Nick approached us to discuss the options available to them, Grant’s products were the first to come to mind. Given the size of the property, the largest of the Aerona³ heat pumps was selected.”

With an A+++ ErP energy rating, Grant’s Aerona³ heat pumps are an effective, reliable, low carbon alternative to traditional heating systems, such as gas boilers. The Lancaster’s home was well insulated with double glazed windows throughout so it was suitable for the installation of a low temperature heat pump.

“The solar thermal system,” continued Dave, “which is easily incorporated into the heating system thanks to the twin coil hot water cylinder, allows the family to harness the sun’s energy in another way, this time heating their hot water.

“We installed an on-roof kit with Grant’s solar thermal collectors situated to the left of the solar PV panels. Opting for an on-roof mounting arrangement was straightforward for this retrofit installation. What was less straightforward was overcoming an issue with the pigeons who took a liking to nesting near the panels! Nick contacted his roofer who sourced some flashing which matched the colour of the solar thermal panels – a novel solution which looks good and keeps the pigeons out.

“The Grant solar thermal system is going to produce much of the family’s annual hot water demand so this will help further reduce their energy bills.”

The family are really pleased with their new Grant heat pump and solar thermal system. “We knew the installation of the solar PV and renewable heating system would be a big project but it has been worth it,” concludes Michelle. “From start to finish, it took twelve days to fit everything and complete the wiring so we took a trip to Cornwall while Dave and the team completed the installation. We’ve returned to a home which is now far more sustainable, which is greatly reassuring for us as we care for Reece and even more so in the current cost of living crisis.”

For further information about Grant’s renewable heating products, please visit