Archania

I am in the unfortunate situation that i am required to bill my landlord for gas and electricity usage for the tenants living above the property i rent for my business, and have recently applied for VAT Registration. We have a single gas and electricity supply for the whole property, the bills are in my name, however the landlord did install submeters so i can bill him directly based on usage. Having read all the documentation, i am still unclear as to if i recharge VAT at 20%. My understanding is, that if i am raising an invoice, to another vat registered business, i would recharge at 20%. However my landlord is disagreeing, stating that i should only charge 5% Vat as that is generally what is charged by the Utility company. I do not want to get this wrong, can anyone advise?