New analysis shows solar panels could save customers £399 per year

Published: 13 June 2023

An independent report commissioned by SLH has revealed the potential impact of solar panels on the energy efficiency of our homes and how customers can get the best from their systems.

We commissioned Sava, a company with over 40 years of experience in ‘Making Buildings Better’, to look at our current building stock, focussing on the 891 homes currently fitted with photovoltaic (PV) solar panels. We asked Sava to look at the impact that the panels have on the energy efficiency of our homes and calculate the average potential savings that customers could expect.

Using Sava’s sophisticated modelling software, we input the details of our PV-equipped homes, including the home type, construction method, existing insulation and other factors to produce an overall SAP figure, with and without PV panels.

And the results were impressive.

Without PV panels, the average SAP rating* of our homes is 69. This equates to average carbon emissions of 2.7 tonnes per year, or an average fuel cost of £662.

With PV panels in place, the average SAP rating rose to 82, slashing carbon emissions by a tonne to 1.7 tonnes per year and average fuel costs to £263 per year, a saving of £399.

What is SAP?

SAP stands for Standard Assessment Procedure, which is how the energy efficiency of homes is calculated, based on heating, lighting, ventilation and hot water systems. The scale runs from 1-100. The higher the number, the lower the average running costs.

Sava’s report clearly demonstrated that PV panels have a significant impact on the efficiency of our homes and customers’ electricity costs. They also recommended that to get the most from the panels, customers should try to use electricity during the day when the panels are producing electricity, rather than in the evening.

PV panels are just one way that we’re working towards a longer-term goal of making all our homes more energy efficient, with our pilot retrofit programme underway and a focus on energy efficiency in all our new build homes.

We’ve also been successful in securing Wave 2 funding from the government’s Social Housing Decarbonisation Fund, which will see poorly-insulated homes receive cavity wall insulation as part of our 2023-24 investment programme.

“We’re delighted to get some real figures on the impact of PV panels in our homes. With ever-increasing energy costs, we wanted to be able to assure those customers who have PV panels that they are a real benefit,” said Angela Perry, Executive Director of Assets and Development at South Liverpool Homes.

“Sava is a trusted name in housing physics and energy modelling, and to see the potential that PV panels have in generating real savings for our customers gives us real insight.

“Their research will help us plan for the future both in terms of retrofitting our current homes and building new energy-efficient homes, which is the foundation of our carbon roadmap to 2050.”

Busting myths and cutting bills

If you’re one of the 891 households with PV panels installed then you’re already reaping the benefits of solar power in your home. But here’s how to get the best from your panels, and a few myths busted for good measure.

• Use your high-energy appliances/devices in daylight hours (washing machine, tumble dryer, vacuum cleaner, iron, electric cooker, etc.) If you can't use them during the day then consider using the timer feature on some appliances.
• Try not to use too many appliances at the same time.
• Turn off any devices which are on standby mode such as your TV.
• Charge devices during the day (e.g. phone, tablet, toothbrush).
• Use LED lightbulbs – they use 90% less energy.
• If you have an electric shower, think about showering in the day. rather than at night.

Getting the best from your panels 

*SAP ratings include just heating, hot water and lighting, and do not include energy used by other appliances like TVs, washing machines and refrigerators. The majority of our homes use gas boilers for heating and hot water so most energy savings from solar panels would be from electrical appliances like TVs, washing machines and refrigerators.