[bpfrh]

It's funny that in this case the law now protects you.

Generally anything you do indoor that falls under normal usage(painting walls, hanging furniture with big screws,etc.) is ok without approval, at least in my country/city(austria) and the land lord can't deny any of this and is not even required to be notified.

As you would have an open window and a not so noise machine running this would be ok, but energy efficiency is quite bad and you lose the benefits of the thermal insulation of your building.