Western MD.
Ball Pythons do need very warm temps, especially after they’ve just eaten.
In their native habitat, however, [they’re from northwestern Africa] they are usually found snuggled into barren termite mounds or abandoned rodent dens.
An analogous place *could* be inside the walls, under the floors, under the house...just ~anywhere~, really.
They are functionally ground snakes, unlike their more arboreal cousins, the Boas but they can and do climb.
Whether he’s hiding up or down is a 50-50 chance.
It’s almost a certainty that it will be somewhere dark and snug.
*That* could literally mean *anywhere*.
It’s truly like looking for a needle in a haystack.
I could be looking for him right beside where he is and the vibrations of my search could cause him to slither back to wherever I just finished looking.
I was assured today by his breeder that he won’t head outside for ‘open ground’.
It’s too much against his nature so he’s in the house...somewhere.
I haven’t read every single post but have you thought of renting a thermal scanner? Anything alive would show up. We had thermal scans done of our home and it was amazing what showed up.