Central hydro air conditioning

Hi All, moved to a new house. I’m based in Asia, in shanghai. Currently it’s very hot and humid. It’s around 39-45 degrees Celsius with very high humidity. The house we have rented has central air con and it’s a hydro version. The landlord claims this is cheaper to run compared to traditional AC systems. Anyways I know now that it takes longer to cool the house compared to traditional AC units but the question I have is the following. Is it cheaper to keep the AC on 24/7? The ground floor is a massive one room with open kitchen, dining area and TV area. First floor has the master bedroom, bath and a guest room. 2nd floor is my daughters room, guest room, laundry room ( no a/c in this room) and my man cave with my gaming rig plus separate bathrooms for each room. Considering the heat during the day and that the temperature doesn’t really drop at night my question is if it would be cheaper / more efficient to keep the AC on 24/7 in the rooms we use. Which would be the ground floor ( this room has 3 separate units ) we can usually manage with 1 or 2 units on to keep the ground floor somewhat cool. We usually switch it off at night and then turn on in the morning and keep on during the day as we have dogs at home. But I just wanted to clarify it would should keep them on or just continue like before and only use them when we use the rooms.
As an example the 2nd floor rooms take very long to cool vs the ground floor.
Any advise is appreciated