I want to give them the benefit of the doubt and say perhaps it's a deep freezer that is only opened occasionally, and I guess is pretty well sealed as long as it's closed.
The kitchen appears to have one of those built-in fridges that matches the cabinets:
The house was built in 1969. Circles were peak modernity back then!
I hatelove this house, you couldn't pay me a million dollars to live there but it is definitely achieving some kind of look....sort of like Flintstones porno set vibes.