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Is an insulation required for the return air duct in a conditioned space?

0 votes
Unit Room is air conditioned without false ceiling. Supply air duct from the air handling unit to other rooms are insulated as well as the Fresh air ducts, but return air duct which carries return air from variuos rooms to the unit are not insulated. Will this cause any condensation on the ducts?
asked May 17, 2015 by Nawaf Hassan

1 Answer

+1 vote
As the return air temperature for comfort cooling is around 75°F (per ASHRAE comfort chart, relative humidity in room shouldn’t exceed 50%), it is usually higher than the room’s air dew point, therefore no condensation will be occurred on return duct surface, and as the room temperature is about the return air temperature, also there will be no energy loss in place. No insulation required for the exposed return duct in space. However the good practice is to draw the air system process on psychometric chart and check the dew point level in room.
answered May 19, 2015 by Matt Hall

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