Dew point

Dew point is the temperature at which the water vapour in the air starts to condense into liquid water. When any surface is colder than the surrounding air's dew point, moisture forms on it — that's why, in humid coastal Dubai, cold AC pipes, supply vents, window glass and toilet cisterns 'sweat' through summer. It's the mechanism behind a lot of 'mystery leaks': a chilled pipe or an under-insulated duct sitting below the dew point drips steadily, and people assume a plumbing leak when it's really condensation driven by high humidity. Two levers control it — lower the humidity (a big part of what an air conditioner does, by condensing moisture on its cold coil and draining it away through the condensate drain) or keep cold surfaces above the dew point with proper insulation and a good R-value. When indoor air is very humid the dew point is high, so even mildly cool surfaces sweat and rooms feel clammy — usually a sign the AC isn't running long enough to dehumidify, or a coil and drain that need attention. If pipes and vents are dripping and the air feels wet, that's the case for AC repair in Dubai rather than just mopping up.