Roger and Vina live in a 50-year-old bungalow in South Somerset. Roger, who teaches energy modules at the Open University has long been interested in low carbon retrofit. In their last home, they installed loft and cavity wall insulation, underfloor heating, solar thermal, solar PV and a Powerwall battery as low carbon retrofit solutions. Since moving to their current home in December 2020, they have started on their low carbon retrofit journey once again.
‘When we moved into our bungalow, we knew it would need upgrading and we have begun a programme of improvements that will take some years to fully complete’
The bungalow has cavity wall insulation and 250-300mm of fibreglass insulation in the loft. It also has double glazing throughout. The heating and hot water was supplied entirely by an LPG combi boiler. That only supplies heat to two bedroom radiators and a bathroom towel rail. Wanting to move away from reliance on gas they now have a couple of electric panel heaters in hall and living room, and a 12kWh Sunamp heat battery for the hot water needs. The heat battery utilises a combination of surplus solar electricity and cheaper off-peak electric to provide constant hot water.
The heat battery was installed in November 2021, with Roger doing all of the plumbing. An electrician installed a new dedicated 16 radial supply from the consumer box in the garage to a cupboard in the hall that now houses the heat battery. Roger arranged for the company that supplied the heat battery to visit after the installation, to officially commission it and validate the guarantee.
With some heating, and all cooking and other day-to-day energy use provided by electricity, their consumption is relatively high. So it made sense to try to generate as much of their own electricity as possible. In March 2021 they installed an 8.47 kWp solar photovoltaic array, along with an EV charge point for their electric car. After being on the waiting list for a year they then had the Powerwall house battery installed. The battery helps make the most of the solar whilst also providing increased resilience when faced with future power cuts. This was proved recently when it kept the house powered during a 7-hour power cut! The Powerwall currently calculates that through the PV and battery system they are currently saving about £2,000 a year taking into account the current energy prices! It’s a fantastic low carbon retrofit strategy.
‘We save money and lower our carbon footprint at the same time’
They had no financial help through government and local authority schemes for the improvements done. In fact, Roger had to take out a personal loan to pay for the retrofit works. He expects to have paid off the loan in three years. Since the Feed-in-tariff ended in 2019, the current scheme, named the Smart Export Guarantee, only pays 4p per kWh for electricity exported to the grid. With the dramatic rise in fuel and electricity prices, this figure is very low in comparison and was one of the reasons for investing in a house battery; to make more use of the solar electricity generated.
Future low carbon plans are to install underfloor heating along with a small heat pump to replace the current LPG system altogether, and to replace some of the poorly fitted windows.
Roger took part in the 3rd of a series of Somerset Green Open Homes webinars. You can view the webinar recording here:
