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This ad may have been parodying the one you're looking for:
https://youtu.be/NUg9oMRZLBU
I will look again for the original.
No luck locating the commercial you described. But LG Art Cool air conditioners are flat enough to be covered by a framed picture, according to ads I've found. Pretty modern!
Edited to add: A search for "items mistaken for modern art" brought up some hits, including this article:
Apparently students now like to put random everyday objects in museums to see what happens.
I remember when the modern art craze was made fun of in cartoons and situation comedies when someone with little art knowledge made a mistake while viewing the art pieces.
Edited by PCD

I need tv commercial for an air conditioner for Mistaken for Exhibit
- A tv commercial has a man impressing a woman by explaining the meanings behind various art works at a gallery. He comes to one that he praises for it sleekness and minimalism... then another lady reaches over and turns the air conditioner on.
Edited by jormis29