What is "superinsulation"

n. 1 The efficient thermal insulation of a building or system , especially by using multiple layers, or low-conducting fibre 2 (context physics English) A quantum state of zero electrical conductivity (or infinite resistance) - the opposite of superconductivity

Superinsulation is an approach to building design, construction, and retrofitting that dramatically reduces heat loss (and gain) by using much higher levels of insulation and airtightness than normal. Superinsulation is one of the ancestors of the passive house approach.