I have multi split airconditioning, with a inverter heat pump similar to the one in Brydo’s picture, that branches off to supply 3 indoor units (lounge and 2 main bedrooms) As well as providing aircon in the warm summer months it can also provide heat. The negative is its certainly not cheap to run especially at todays energy prices. In the summer you get a constant noise from the unit when its on, even if sitting round the corner from it. Unless it above 24c in the house during the summer it stays off and at most run for a hour or two just to coll the bedrooms.