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. Definition There is no universally agreed definition of superinsulation, but superinsulated buildings typically include: Very high levels of insulation, typically R-40 (RSI-7) walls and R-60 (RSI-10.6) roof, corresponding to SI U-values of 0.15 and 0.1 W/(m²·K) respectively) Details to ensure insulation continuity where walls meet roofs, foundations, and other walls Airtight construction, especially around doors and windows to prevent air infiltration pushing heat in or out a heat recovery ventilation system to provide fresh air No large windows facing any particular direction Much smaller than conventional heating system, sometimes just a small backup heater Nisson & Dutt (1985) suggest that a house might be described as "superinsulated" if the cost of space heating is lower than the cost of water heating. Beside the above mentioned meaning of high level of insulation, the terms superinsulation and superinsulating materials is in use for high R/inch insulation material like vacuum insulation panels (VIPs) and aerogel. Theory A superinsulated house is intended to reduce heating needs very significantly and may even be heated predominantly by intrinsic heat sources (waste heat generated by appliances and the body heat of the occupants) with very small amounts of backup heat. This has been demonstrated to work even in very cold climates but requires close attention to construction details in addition to the insulation (see IEA Solar Heating & Cooling Implementing Agreement Task 13). History The term "superinsulation" was coined by Wayne Schick at the University of Illinois Urbana–Champaign. In 1976 he was part of a team that developed a design called the "Lo-Cal" house, using computer simulations based on the climate of Madison, Wisconsin. Several houses, duplexes and condominiums based on Lo-Cal principles were built in Champaign–Urbana in the 1970s. In 1977 the "Saskatchewan House" was built in Regina, Saskatchewan, by a group of Canadian government agencies. It was the first house to publicly demonstrate the value of superinsulation and generated a lot of attention. It originally included some experimental evacuated-tube solar panels, but they were not needed and were later removed. The house was heated primarily by waste heat from appliances and the occupants. In 1977 the "Leger House" was built by Eugene Leger, in East Pepperell,