23-11-2013, 04:56 PM
As above, air con dehumidifies the air (hence it needing the drain on the bulkhead to dump the water). Lower humidity allows the air to heat up quicker (humid air is more dense) and stops the windows steaming up, that's why the AC comes on with the recirculate function, and in most cars if you turn the dial to 'windscreen only' it'll bring the AC on as well. If you recirculate warm damp air then that moisture will keep condensing on the windows without the AC working and the heaters will still take a while to fully heat the air.
Obviously it will stop eventually, as there are air ducts at the rear end to allow 'used' air out, but the AC makes the process much quicker.
Obviously it will stop eventually, as there are air ducts at the rear end to allow 'used' air out, but the AC makes the process much quicker.