[Porsche-O-Phile]

You sure it's not being built as a telco switch building? A lot of times those are located in residential areas and the towns require efforts be made to have them at least sorta appear residential, but for obvious reasons (typically unmanned infrastructure) they can't have blatant exploitable points of access like windows. Just a thought - Ive designed several of these and that's kind of what it reminds me of, especially if there are large elec cabinets with disconnects... Oversized HVAC and/or undersized (or non-existent) plumbing would also be signs. Utility equipment generates a fair amount of heat.

If it's clearly a private party I'm guessing grow house or meth lab.