Thundie
Sapling
Yea, I have a thermometer outside, it is usually between 5 and 10 degrees warmer. It's south east facing so it depends if the sun is out or not. When we get around -5 I tend to open the glass panels on sunny days. Floor is also carpeted and off the cold concrete.Have you taken a temp reading on your enclosed balcony? Maybe just a supplemental heater will raise the temp enough to stay above freezing..
Don't really have a good pic at the moment and can't take now as it's pitch black, but here is basically what I mean. It's about 3m long with my trees tucked up against the apartment wall in the corner on the left out of the pic. You can see examples of other apartments in the background. They have the same as me