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

All that matters is output and efficiency. So when one dies the replacement doesn’t need to be the same, just have a similar output with hopefully better efficiency.

Also, not all apartments in a building have the same layout. Some are bigger and therefore need units with larger outputs.