> There's _some_ tension with insulation there, though really at this point it's largely surmountable with triple-glazing etc. A typical triple-glazed window c

> There's _some_ tension with insulation there, though really at this point it's largely surmountable with triple-glazing etc. A typical triple-glazed window can maybe hit R-8 (U 0.125). A typical wall can be R-20 (or greater). There is no surmounting, relative to other assemblies, the suckiness of glass as an insulator. But few people want to live/work in an bunker with no windows if they had a choice, so we accept the compromise. But make no mistake it is a compromise when it comes to energy efficiency.