For no water or air conditioning, I'd expect a full refund for those days - period. (Aside from the previous caveat about being in a part of the world where this is expected at a hotel...)

I've only had this happen to me once: I was checking in to a Residence Inn in downtown San Antonio one evening when they'd had a water main break. They didn't even let people check in to the hotel - instead, the manager informed me of the situation right upon arrival and offered me my choice of any other Marriott downtown at my existing rate. (There are about 10 of them within a couple miles of downtown.)

I picked the other Residence Inn a few miles away, although it was clear that I could have picked one of the two or three full-service Marriotts that typically run a somewhat higher average rate. All in all I thought that was fair.

I didn't stick around long enough to figure out what they were doing with people who were in the middle of their stay.