VAT on solar extension

I have a solar installation of 20 panels and am investigating adding 4 panels and a battery. Is VAT chargeable please?

Hi,
If you are adding solar then the  materials and installation can benefir from the energy saving relief.
If batteries are installed then as long as the installation of both solar panels and battery is completed as a single supply of services then this can benefit from the relief
Please see the guidance below:
Installations of energy-saving materials
Thank you.