Air Conditioning - Window Ac in wall?

can I install any "window" AC unit through a wall, or does it need to actually go through a window?

No, it does not need to go through a window. I've not done it but have seen units mounted through a wall.

One problem you might find is the power cords on window units usually aren't very long.

I think if you check most window units wont work in a wall. The wall will cover up some of the side vents and you cant have any of the vents covered up. If you check the wall units are in a sleeve set up. so they can slide in and out.

the key is how much room is on the sides of the unit, i believe. if there is enough room for air to flow thru the side vents, u should be fine. if the unit is exactly the size of the sleeve, though, it doesnt give the vents any room to breathe. so if your "sleeve" or wall opening is 26" wide and the unit u are installing is 21" for example u should be ok. just dont block off those extra 5 inches.

what do the rest of u guys think??

When trying to install a window unit in a wall you need to have all of the side vents at least 3/4" out past the wall.
If you have the vent area inside the wall there is a high likelyhood that water will get into the wall cavity.

Most standard walls of 2x4 construction do not accept the installation of a wall unit very well.
I have on occasion been forced to do this but had to make the outside hole larger than the inside to keep the vents free.
This takes some creative carpentry to do and in your case it would make spending the extra money on a casement unit well worthwhile.

Great info, thank you. Does anyone have a recommendation on a wall unit? I am trying to cool about 1,100 square feet of dinning space, in my pizzeria with an open kitchen. I have about 3 tons now, which doesn't do the job. I am only trying to find an inexpensive "patch" until I can afford to do the job properly.

A pizza restaurant is a far cry from a residence which is what this forum is for but for your dining room you would need at least a 24,000 btu commercial unit.
You have to consider the cooking equipment and exhaust fan will add a tremendous amount of heat and air change.

I have been working with the restauranteurs for many years and understand the nature of finances but if there is a way to get this much cooling you won't have to worry about it for a long time.

And no, a 10,000 btu unit from Walmart won't be enough!

sorry, I didn't realize this was only for residences. Thank you all for your help.

No, that's ok.

One thing that you could do is use two 12,000 btu units.
This would be a bit quieter and also distribute the air better.