It can be done with heated, after conducting hot water or laying the heating cable. But if the old radiator batteries with new ones on the balcony cannot be replaced by the furniture while furniture is carried out. The balcony also needs to glaze. Installation of a three -chamber PVC package is one of the best options for warm glazing. There are a lot of wall demolition options, but the best in this case is when an increase in the window opening and the installation of the table is made instead of the windowsill. If there is a difference of floors between a room and a balcony, you can build a step. And you can use the newly acquired area at the discretion, for example, build a recreation corner or install a small bed. It all depends on what size the balcony.