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Insulation on an air handler

but unless your air handler has decent internal insulation, I would be more concerned about condensation outside the AHU, dripping onto the attic floor, making an absolute moldy mess of things. Bad enough if indoors but in a well ventilated attic could spell disaster, IMHO. Chances are it has some internal insulation but I would be surprise if it was more than half an inch to an inch and if it covered the corners and access doors well.

An external wrapping job with scrupulous sealing of seams is crucial but will block access to filters and coils. Expect to destroy the insulation job and repair or replace it at service time. (This is another reason I like filter return grilles.)

Yes ventilate the attic of course, but do not expect the temperature to get anywhere below ambient, rather it will be about 20-30 degrees above ambient. (Cannot get to 90 degrees using 95 degree outside air you know :)


  • Dan_29
    Dan_29 Member Posts: 111
    Insulation on an air handler

    I have recently had a split central a/c system installed in my single family residence. The system is properly sized and services the first floor from a basement air handler due to a need not to tear up to many walls or ceilings in the duct installation.

    An air handler located in the attic supplies the second and third floor with air via knee walls. The flexible ducts are insulated. The air handler which they are connected to has no insulation on the exterior. I am concerned that the air handlers lack of insulation and very hot air temperatures,in Summmer, will reduce my system efficiency and cost more money to operate the system.

    I am considering doing two jobs to increase system efficiency. The first is power venting attic via the gable vents. The second is installing an exterior insulation jacket on the air handler.

    Are the above two tasks worth the effort in terms of increased system efficiency and money saved? Is there anything else I can do to make the system more efficient and save on my electric bill?


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