Hi.
The 0% VAT in relation to energy saving materials is for the materials and installation of these materials. You can see guidance here:
Energy-saving materials and heating equipment (VAT Notice 708/6)
Where the installation of energy saving materials involves anciallary supplies please see section 2.7.2 of the following guidance:
Installations of energy-saving materials
If existing solar panels are upgraded then this can be installed at the 0% rate of VAT as long as the criteria is met in the above link.
The 0% VAT would relate to the materials and to the installation of these materials but would not include services like scaffolfing which are not of themselves energy saving materials or installation services.
We would recommend looking at the guidance carefully and if you feel that the guidance does not fully answer your questions then you would need to put your queries to our Written enquiries Team.
VAT: general enquiries
Thank you.