Many thanks for the replies.

I understand what you're saying. The measurements from the Efergy meter is probably wrong because of the reactive component. From the 2 pieces of equipment (heat pump & kitchen hob) I'm seeing them register around 650W combined on standby...

But... the amount I'm being ...

Apologies for English.. my Portuguese isn't good enough for this technical subject.

I have residential premises in Portugal and a Daikin Air Source Heat Pump for hot water & underfloor heating. It has always seemed expensive to run so I thought I'd install an energy meter to monitor consumption ...