Battery storage is recorded as part of the EPC assessment under RdSAP 10, but it usually has little to no effect on the actual rating. EPCs are based on modelled energy costs rather than real usage, so unless a battery is specifically set up to cut electricity demand at peak times, it won’t meaningfully lower the estimated cost used in the calculation.

Batteries paired with solar can be genuinely useful in practice, they just don’t tend to move the needle on your EPC band yet. That could change as time-of-use tariffs and smarter systems become more common.