Say, at 18C - does it still work? Maybe 100 times slower, but still work? Or you have to reach 65C for it to evens start working?

I have a large number of plastic things inside my home that I hope do not become decomposed.

Garbage, sure, decompose away.

It’ll eat everything inside!

It might be extremely toxic.

I suspect that your parents' neighbor would already be unhappy if someone smashed their house into micron-size particles, heated it to 155˚F and kept it there for many hours.

At that point, not having the PET broken down into monomers is a pretty lousy silver lining.

(Seriously though, it needs fairly particular conditions to work.)

Don't be histrionic, the PET they did this with wasn't in large chunks, it was processed into a powder (with particle sizes between 200-500 micrometers). This enzyme would be less harmful to their house than rubbing it with acetone.

If you're heating the whole house to 65 degrees, as required, that is probably the least of their worries.

And it's not like the ability to dissolve plastic is new; there are plenty of solvents which will do this for various plastics.

Was it 3-D printed?

I was going to say that it probably isn't PET, but a bit of Googling quickly turns up articles about people making houses out of recycled plastic. If that's what it is, it could well be PET.