Taxation of the rental service along with the supply of electricity, which VAT rate to apply?

Due to the temporary reduction of the VAT rate from 23 percent. at 5 percent many landlords had doubts as to whether they should invoice electricity together with the lease at a 23 percent rate, or treat the electricity supply as a provision separate from the rental service and tax it at the 5 percent rate.

Source Archiwum

See also ECJ Case C-42/14 (Wojskowa Agencja Mieszkaniowa) – Letting of immovable property and the provision of water, electricity and heating must be regarded as constituting several distinct and independent supplies