I'll be interested to see how people use them in the UK, because most people don't have a balcony and most people don't have outdoor sockets they can plug them in to.
Cut moulded mains plug off the end, drill hole in wall or window frame, feed cable through, put a new 3 pin plug on the end, job done. That's how I'll be doing mine. If you've got a mains socket near an external wall on a ring main though (it'll have two twin and earth cables going into the back of the wall socket) you can run a spur to an external mains socket and under the regs it's also something you can DIY without needing an electrician.