Why do some buildings have multiple, different types of A/C units?

Question

I just saw 6 individual units lined up outside an apartment building but only 2 were the same kind.

In: 1

Answer 1

During the original construction all six were probably the same, but four have failed over the years and been replaced by different tenants.

For non-residential buildings, it’s common to have different sized HVAC equipment for different sized interior spaces. The front offices and the cavernous loading dock have different needs.