Mitsubishi mini split: 2 x 12K=24K?

vivi

I have a 10 year old Mitsubishi mini-split indoor unit, MSY-GE18NA cooling only. It is 31 7/16 wide. I want to replace it with a heat pump. The existing unit is installed in a 450 sq ft room, on the left side of an outside wall with 36" of space on each side of a wide window. 3 Mitsubishi Diamond contractors have proposed to replace it with a MSZ-GL18NA. The problem is that the MSZ-GL18NA is 36 5/16 wide. It won't fit in that space. When we pointed that out to the contractors, one suggested a floor unit, which is not practical in our situation. Another suggested, after consulting with a Mitsubishi rep, a 18K Designer Series unit, MSZ-EF18NA, which is smaller (34 13/16" ), but has a much lower air flow rate. This also seems to be too wide if you allow for enough space to access the inside for maintenance or repair.
I was wondering if installing two 12K units, MSZ-GL12NA, one on each side of the window , would work. Any advice? I uploaded a picture of the wall with the unit we have now.

mattmia2

Is the ceiling accessible from above? There are units that can install in the ceiling.

Hot_water_fan

The MSZ-GL15NA is 31 7/16 inches and actually has higher cooling capacity than the existing one.

pecmsg

18K is a lot of cooling for 450 Sq Ft. 

Where is this house located. I only see 2 outside walls and assuming conditioned space above and below. 

GW

Yes some hvac guys will jam em into a corner- not good. 

A 15 was suggested above, do that 

——of shoot- what you have is 31”? Oops. Can’t get the blower wheel out easily. Gotta yank the blower motor