I worked on the balcony in the winter season 2022-2022, it was from -10 to -30 outside the window, the temperature inside was from +15 to +22, and then when you warm yourself with your warmth and breath, at maximum settings. There is no warm floor. Tolerably, you can live with it, but I would not recommend you to buy for 1kW and with a useless infrared feature. See more power and without infra + be very careful about thermal insulation and leaks through the adjoining windows and window sills. Ideally, you need a good warm floor, not a heater.
As promised, I have included some photos to give a visual of my experience.