I don't understand why the central heat and air in my rental property has to be depreciated over 27.5 years! That is certainly not its "useful life"!
The primary reason is because it becomes "a physical part of" the primary structure. It's not like a window A/C unit. You can remove a window unit in about 10 minutes and it has absolutely no effect what-so-ever on the value of the property. But if you remove a central air unit, that will significantly reduce the value of the property and you definitely won't be able to sell it for anywhere near the price you could get if you leave the central air installed.
Another weird one that has to be depreciated over 27.5 years, is a new water heater. Even though it cost less than $800 it still gets depreciated over 27.5 years. That's because a water heater becomes "a physical part of" the plumbing system, which itself is already a physical part of the main structure.
