Debbie says 'I tried to warn you.'
https://www.independent.co.uk/news/uk/home-news/air-source-heat-pumps-energy-bills-uk-b2249088.html
It would be the same or more if he had gas.
I suspect its not a small house.
QuoteSteve, a company director from Harlaxton, Lincolnshire, who started using the system in July said: "The equipment cost £17,000, then there was the installation so add another £10,000 at least.
Thats not a small heat pump. Ours installed was £7,000 and the bills are £2000 p.a. and the house is set at 21 degrees, as its rental.
QuoteThats not a small heat pump
Compared to what?
World's largest CO2 heat pump with 70MW capacity begins operation to power 25,000 homes
https://www.msn.com/en-us/weather/topstories/world-s-largest-co2-heat-pump-with-70mw-capacity-begins-operation-to-power-25-000-homes/ar-AA1v3Szb