If it would add to the Basis of the property it would be a "Substantial Improvement".  Or another way to look at it, if it was a rental property, would it be depreciated over 27.5 years?
https://www.irs.gov/publications/p936#en_US_2018_publink1000230004

Based on that, I would lean towards that a built-in system may qualify.  I would view it as comparable to light fixtures or a security system, which are §1250 property