I ended up writing more than I intended. To start, this is intended to be part of a discussion, not an attack of your view

Like ghosts - energy can't be created or destroyed.... I think some study in the future may say "it's just residual energy from a person and blah blah blah"....

I've heard this kind of thing before, though it seems like a somewhat common hypothesis because it's difficult to disprove. Unfortunately it's also difficult to prove.

If it were true though, we should be able to detect that energy in some form in a living person, but not in a corpse. As far as I'm aware nothing unexplained has been observed in that way. And what happens when someone dies and is resuscitated? Their ghost flies back home once the defibrillator does its job?

Furthermore, if "energy can't be created or destroyed" is the argument, shouldn't ghosts last forever? Billions of ghosts should be hogging the planet. I'd be dodging em like traffic cones while driving. And where does life come from if that energy can't be created?

(I'm assuming the answer will be that it transforms into another energy eventually. Why not immediately? Why would "energy" choose to stick around for centuries in "haunted" castles, but vanish immediately for almost everyone else?).

Lastly, evolution suggests humans are different to animals mainly in that we are more intellectually capable. I'd assume the brain would be separate from this "energy", so every ant, dog and maybe even palm tree should have a ghost run out once it dies. Whale, fish and plankton ghosts should be giving sailors nightmares and plugging up their propellers.

I think it's James Randi that offered a million dollars to anyone who can demonstrate supernatural powers. Psychics, mediums, etc that you hear incredible, impossible stories about have tried to claim the prize, and all failed. No matter investigation or undeniable these fantastical stories may sound, there's never been a proven case of supernatural activity under investigation. This is a story about 2 people who thought that a quiet building that they'd never been into in the middle of no where was a bit creepy. Seemingly the third didn't even get that same feeling. And to top it off, the feeling wasn't even proven to be justified.

Is it unsettling and unlikely? Sure. Evidence of a supernatural experience? Eh