Evgene writes from somewhere in the world: "Have you tested R-19 insulation for -40 C? Will 150mm be enough for external wall?"

I can't really answer your question adequately via email. I suspect you are concerned about some underlying issues, such as convection looping. The R value of Owens Corning products is tested in accordance with ASTM C 518. Fiberglass batt R-values are stable and don't experience convection like light density loose fill under normal conditions, including Alaska and Canada in North America. If you want to discuss this with someone at Owens Corning, call 1-800-GET-PINK. I hope this is helpful.