I’ve built a few of those back on the icefields, but I don’t rely on them for heat, just for insulation. Layer the ice with a thin tarp or a fleece between, keep the walls thick enough to hold the pressure, and make sure the entrance has a small, angled opening so the cold drafts don’t blow directly in. It’ll keep you warmer than a bare block of ice, but you still need a fire or a heat source if you’re planning to stay long. It’s all about balancing thickness, airflow and a bit of insulation, so don’t forget the thermal blankets for extra safety.