. . .a thermostat?
FFS, just spent half an hour on the phone with him explaining that the reason the number keeps jumping back to 24 when he's turned it down to 18, is because that is what fucking temperature the room currently is!
DH pissing himself in the corner as I say, 'if you want the number to go down, the house has to get cooler. Open a window!'
FIL: 'so I should just leave it alone now?'
Me: FFS Yes, go to bed! 'Yes, just leave it now, it should get cooler overnight'
They've just had the new boiler installed and every day is a new tale of woe, which is probably our fault for telling them who we used for our boiler.
Roll on Christmas.