BEST SETTINGS FOR A/C EFFICIENCY

Just my opinion, but there are so many variables.  Generally speaking, it takes much more energy to cool a room, and the furnishings, than to keep it cool.  If you are leaving home, but returning in an hour or so, I say leave the AC running.  If you're leaving for the whole day, shut it off.  For sleeping, I have found NOT having a ceiling fan running more efficient and comfortable if you are using AC.  I turn the bedroom unit on about 10 minutes before going to bed, hit Turbo.  Once I'm comfortable, Turbo comes off.  If your home is built smartly, the bedroom AC unit will be placed so it passes either across the head of the bed, or from the head of the bed down to the foot.  For me, I turn the Swing setting off, with the outlet angled so the breeze passes just over the entire bed.  This means you can have the fan speed set to medium or low, or possibly set it to Dry which uses less electricity but puts out colder air.  On Cool and medium fan speed, I was using 1.6 kw, but in Dry it dropped to 1.2 kw.  This time of year I find Dry too cold, so the temp setting goes up and the fan speed drops to Low.  Play around with the settings, but all that matters is that you are comfortable.  There's no point in installing an AC unit if you're not going to use it.

Heat insulation matters.

Single glazed windows and walls with limited insulation bleed cold air, and they act as radiators when the sun hits them.

Climbing plants on outside walls offer a lot of shade.

Reflective window film gets rid of a lot of heat before it enters the room.

Thick curtains are also very helpful.

So many things we can do to make the  a/c more efficient.  If you on the home or are building all the comments above help. If you rent then  do the most cost effective.

An added item -  make sure to keep the a/c maintained properly! Cleaning it regularly keeps it more efficient