Bur Dubai's old buildings — why does the AC here sweat, drip and smell more, and what actually helps?

It's both the location and the age, and the good news is it's fixable, not something you have to live with. Bur Dubai near the creek runs genuinely humid, and humidity is what turns ordinary AC into sweating pipes, drips and musty smells, because the system is pulling a lot of moisture out of the air and every cold surface wants to condense. In older buildings three things line up: chilled pipework whose insulation has perished (so it sweats and drips instead of staying dry), a condensate drain that's partly blocked or badly sloped (so water backs up), and a coil and drain pan that have grown the biofilm that gives the sour smell on start-up. None of that is the AC being dead. A proper service that re-insulates the sweating sections, clears and re-slopes the condensate drain, and does a real coil-and-pan clean stops all three. Getting AC repair in Bur Dubai to look at the drainage and insulation specifically, not just gas, is what actually fixes the humidity symptoms here.