Adequately insulated?

This is a view from the uncompleted wood storage shed to the small insulated studio building. We just spent the past week there checking out if our insulation work over the summer was adequate to keep us warm in the winter months. So at minus 15 Celsius we were cosy. Can we remain as warm when it dips to minus 30? Yet to be experienced. Maybe January will throw some seriously cold weather and we will see how well we did our job.