I am looking at replacing my old central AC unit with a heat pump one using existing ductwork. A contractor quoted me Fujitsu Airstage indoor unit AMUG48LMAS with outdoor unit AOUG48LMAS1. I checked the Fujitsu website and it reads


Can a unit designed for mini-split system be used for central AC ductwork?

1 Answer 1


There are many types of mini-split systems. The more familiar use of that term is when referring to a wall-hung ductless indoor unit; however, mini-splits are not limited to ductless indoor units. There are ducted indoor units, which can still be called mini-split systems.

The indoor unit you reference is a ducted air handling unit. The limits of its use will be the total cooling and heating capacity, the volume of air that the fan can move, and the friction loss of the ductwork used to distribute that air.

According to the specification sheet for that unit, it is capable of the following:

Heating & Cooling Capacities (Btu/h):

  • Cooling, rated for 45,600 (13,000 min - 48,000 max)
  • Heating, rated for 53,000 (11,000 min - 54,000 max)

Indoor Fan (CFM):

  • High: 1,640, Med: 1,020, Low: 820, Quiet: 590

Whether or not this unit meets the requirements of your system needs, I can not say.

  • With these specs, could you please suggest what would be the trade offs of this system vs a dedicated 4ton/48000btu central AC unit?
    – ahala
    Nov 9, 2023 at 0:33
  • 2
    This is a 4-ton central AC unit.
    – pdd
    Nov 9, 2023 at 0:43
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    @ahala -- ducted minisplit air handlers (especially the compact "pancake" units) have lower rated static pressure than their "traditional" North American counterparts, which means you have to pay more attention to duct design instead of slobbering flex duct everywhere, only to have it to turn into an air-conditioner-strangling ductopus on you! Nov 9, 2023 at 4:39

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