# AC Temperature Drop ?



## We Fix Houses (Aug 15, 2007)

Quick question ? Maybe its a quick question.....? 

In a split system forced air AC (nearest the air handler) is there an expected temp for the supply or what should the temp drop be from the return to the supply ?


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## Tom M (Jan 3, 2007)

I think about 15 degrees is the ideal difference


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## flashheatingand (May 3, 2008)

About 20 degree split.


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## kooltech (Apr 1, 2011)

In humid climates, an 18-20 is best or the home may too humid and feel warmer than need be. Black matter can develop (the stuff we don't like to talk about). We have that situation here where I am.
In dry climates areas, a 15+ seems to be acceptable.

Keep in mind- this split won't diagnose a problem with the system and the system must have been running for at least 15 minutes and the home already in the comfort zone. If the a/c was off and the home humid and hot- air split readings can be useless.


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## MechAcc (Feb 27, 2005)

I can't recall where I found this chart measure return air dry bulb and wet bulb temp and the intersect gives you a target temperature drop. You'll note that as the wet bulb temp increases the actual temp drop decreases. This is due to more latent heat being removed.


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