My through the wall air conditioner is no longer working. It is a Carrier GCA051B installed in 2001, with a sleeve.

Assuming the sleeve is ok, what do I replace it with? It looks like the model is a window unit, used with a sleeve. Can I use another window unit of the same size? It covers just a 12x15 bedroom.

Any advice will be greatly appreciated.

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2 Answers 2


First, if it works even at all, check with your power company about any appliance upgrade assistance they may have. They will often subsidize replacement with efficient appliances, especially air conditioners, because every watt of A/C draw they eliminate is a peaking unit power plant they don't have to build. Peaking units are by far the most expensive because the bank wants the mortgage paid exactly the same as a baseload 24x7 nuke, but the peaking unit only makes hay a few hundred hours a year.

There's window units, and then, there's wall units.

Wall units are much tougher and more industrial units than window air conditioners. They also have a much tougher and more industrial price :)

As such, people like to substitute for window units, which is not a good idea. Window A/Cs assume a threshold only a few inches wide, especially on the top. The wall passage tends to be deep, and the window unit won't perform well there.

One could install a window :)


Yes you can replace the unit make sure the vents are in similar places you don’t want the sleeve blocking outside air flow normally on the sides and back. Also make sure the unit tilts slightly to the outside so the water can drain outside.

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