What about using a heat pump with AC? They might end up being more suitable for your layout.

where to place air conditioning units?

WHY use a Window Air Conditioner vs Ductless Mini-Split Cooling System.

https://www.ductless-mini-split-air-conditioner.org/

Ductless Mini-Split Air Conditioners.

May cool multiple rooms – can manage up to four units when connected to one outdoor condenser (you can add another outside evaporator) to cool more rooms.

You’ll have install flexibility – you can hang units from walls or suspend them from ceilings, while managing them all with a remote-control device.

Whisper quiet units – unlike noisy window ACs.

They keep you safer from outside threats – since ductless units only need a small hole (impossible for a human burglar to enter) for installation.

AC WINDOW:

Keep in mind that there is a security risk with a window air conditioner. There is not much holding it there beside its weight and removal from the outside (depending on where it is located) could provide an easy unwanted entry into the home.

Tend to be noisy – the more you pay for window units, the less the noise. But, even more expensive window units, typically, are rather noisy, particularly, when going through their dehumidifying cycle.

They can lead to lack of security – since burglars can remove window ACs from the outside, they could enter your home through the open window.

Window ACs reduce natural light in your home – as you fill a window with an AC unit, you’ll lessen the natural light your home’s interior usually enjoys.

They are not attractive – manufacturers always choose efficiency over aesthetics for window units.

Hi, it's not a window unit, it's central air units near a window ... looking for pros/cons

Is there any intermediate roof level where you could put one without deafening a bedroom, etc.? otherwise, side by side seems best.

Compressor units must be spaced apart to allow adequate airflow or efficiency is impaired, and can lead to operational and failure trouble.

The condensers need room to breathe, room to be serviced, repaired etc.

Placing near a window is fine as long as it's not a bedroom window as noise may be an issue for some units. (cheaper are noisier, and noise is subjective... some people complain about pins dropping--- even the quiet units make *some* noise)

In terms of aesthetics (looks) --- some people would like to be comfortable --- if your goal is hide them so you can't see them, this isn't productive during a heat wave. The hotter it gets, the more you will wish you had not been so picky in trying to hide them. (they don't work via magic, science only here)

In best cases I like to see 3 feet clearance around all sides except for the back side up against the wall 2 feet is fine. I wouldn't 'stack' them. You're asking for a lot of trouble if you do that.

One should fit well in the cut out. If they are different sizes then see if the bigger one can go there. I would put the second one behind the house to the left of the cut out of your diagram. This would hide it when looking from the street. The drawback it is right below the back widow. If you want a clear view of the backyard then move it to the left 4-5 feet so it is less noticeable when you look out.

Thank you the comments are helpful

Should have gone heat pump . Now ask the architect what they were thinking of for units to fit that space. Would it not be possible to just get one bigger unit to handle it all.

I do not like condensers under a window....you need at least 3 ft clearance on at least 3 sides of condenser, 2 ft on side next to wall...if side x side for other condenser, again plenty of clearance btw the two...

I don't see how changing the AC condensers to heat pumps helps the physical placement of the equipment. They are approximately the same size. It is late to think about zoning the two floors or tying the two floors together. I personally would not give up having two systems so there is one less condenser on the back of the house.

I also don't like the condenser under the window. I would move it so it is out view. There are ways to hide it as long as you maintain the minimum clearances.

How big are the units you are spec'ing (tonnage, dimensions). You might get two smaller units in that space. Ideally you want over a foot clearance but, depending on your circumstances, you can get away with a little less. You'll loose a little efficiency but it shouldn't be too much. What are the dimensions of the space you have there (5' by ?')?

Finally got to measure, the cutout is 2 feet x 4 feet

Thanks everyone.. we will use the slim line - and place one in the cut out on the back right side of the house and one on the back left side of the house... hopefully it will work