Will Battery Storage Improve My EPC Rating Under RdSAP 10?
As more homeowners install solar photovoltaic (PV) panels, battery storage systems are becoming increasingly popular. A common question is whether adding a battery to an existing solar PV system will improve an Energy Performance Certificate (EPC) rating.
The answer is potentially yes. Under RdSAP 10, the methodology used to assess the energy performance of existing homes in England and Wales, battery storage systems can now be taken into account where sufficient evidence is available.
However, the impact on an EPC rating will vary depending on the property, the renewable energy system installed, and other energy efficiency measures already present.
What Does a Solar Battery Do?
A solar battery stores excess electricity generated by solar photovoltaic (PV) panels during the day so that it can be used later when the panels are producing less energy, such as during the evening or overnight.
Without battery storage, surplus electricity is often exported back to the electricity grid. With a battery system, more of the renewable energy generated can be used within the home.
Can Battery Storage Improve an EPC Rating?
Under RdSAP 10, battery storage systems can contribute positively to a property's EPC assessment.
Battery storage can increase the amount of renewable electricity generated on-site that is used within the dwelling, reducing reliance on electricity imported from the grid. This may improve the property's calculated energy performance.
However, the actual impact will depend on several factors, including:
The size of the solar PV system.
The capacity of the battery storage system.
The property's energy demands.
The heating and hot water systems.
Other energy efficiency measures already installed.
The evidence available to support the installation.
How Much Could My EPC Rating Improve?
There is no standard increase in EPC rating from installing battery storage.
The greatest benefit generally comes from the solar PV system itself, with battery storage providing an additional contribution by improving the use of renewable energy generated by the property.
For some homes, battery storage may contribute only a small number of SAP points. For others, particularly where larger solar PV systems are installed, the impact may be more noticeable.
The overall EPC rating will still be influenced by factors such as:
Insulation levels.
Heating system efficiency.
Hot water provision.
Windows and glazing.
Lighting.
Renewable energy technologies.
What Information Does the Assessor Need?
If you have installed battery storage, it is important to provide supporting documentation where available.
Useful evidence may include:
MCS certificates.
Installation certificates.
Manufacturer specifications.
Battery capacity details.
Commissioning documentation.
Providing accurate information helps ensure that the system can be correctly recorded during the EPC assessment.
Are Solar Panels More Important Than Battery Storage?
In most cases, the solar PV system itself will have a greater influence on the EPC rating than the battery storage system.
Battery storage is designed to maximise the use of renewable electricity generated by the solar panels, helping homeowners make better use of their renewable energy investment.
Both technologies can contribute to improved energy performance, but battery storage should generally be viewed as a complementary technology rather than a replacement for solar generation.
How A1 Home Inspectors Can Help
At A1 Home Inspectors, we assess properties with a wide range of renewable energy technologies, including solar PV systems and battery storage.
If you have recently installed renewable energy improvements and would like to understand their potential impact on your EPC, our assessors can help ensure that relevant information is accurately reflected within the assessment process.
Need an EPC for a property with solar panels or battery storage? Contact A1 Home Inspectors today to speak with one of our assessors.
Disclaimer
The information provided on this page is for general guidance only. The impact of battery storage on an EPC rating will depend on the assessment methodology in force at the time of inspection, the evidence available to the assessor, and the specific characteristics of the property and renewable energy system installed.
