Hi KimSim, the installer came and check. Told me there's no leakage, pressure is alright etc. So will it really be gas shortage causing the problem? or will it be possible the new MHI hardware already have some issue? if i switch to 24-25 degree, the aircon is worst than mrt or bus cooling, its definitely not normal right? My room is not that big, its a 4rm resale. Even if i just on one aircon unit, the cooling is still not enough to me. =(