casing yellow, remove and repaint.
if very old (maybe over 15 years) and non inverter, you save money to new inverter model with tnb.

Electricity consumption is key. Just changed to new one, TNB bill a lot cheaper. 247 user here

more on energy usage and if still feels cold
if both is not good, can consider a new one

My house have all non inverter including mine the bill always RM300 - Rm400

My non inverter aircond spoiled so i change to panansonic 5 stars inverter guess what now the bill only RM200 - RM240

I turn on 24/7 but temperature must set 24 and above also the room must be able to retain the coldness or else there no saving because aircond cannot cut compressor because cannot reach the set temperature.

this is my st rating

It’s written in the photo look closer
Brand is Panasonic