I’ve found that my bamboo garments stretch out and pill. Is that a common thing for bamboo or did I get unlucky with the quality?

In Sweden 20°C is the lowest acceptable indoor temperature for apartments.

I lived at a place that had 17-19°C indoors for a while. Spent all my time nestled under triple blankets. Sitting still at those temps gets real cold after a while, unlike being outdoors where you’re more likely to be moving (and maybe get some sunlight to warm you up, too).