李老师讲的alternative这是说反了吗？

The second type of depreciation is referred to as functional obsolescence. It is a loss in value due to a design that is different from that of a new building constructed with an appropriate design for the intended use of the property. 这是functional obsolescence的定义，也就是说这个不好的或者说过时的设计，会降低replacement cost.

Functional obsolescence usually results in the building generating less NOI than it otherwise would because the building may be less efficient and have a higher operating expense or may not command as much rent as a building with the proper design.

这里空调成本是一个incurable functional obsolescence，是需要减去的，可以这么理解，由于层高带来的多的空调成本本来是不需要的，现在要承担这些多余的空调成本，就会降低房屋本身的价值。这个可以和少赚的NOI一起来理解，一方面是成本增高，另一方面是收入减少，都是会降低房屋的价值。