And with loose fill cellulose in the walls, and just 1»
rigid foam insulation around the slab perimeter near the bedrooms (9 to 12» down in the soil), the heat loss would be about 35W / F temperature difference.
(clockwise from top left) the ground floor was excavated and
rigid insulation placed
around the perimeter to cut thermal bridging here; airtightness taping
around joist ends; new roof rafters insulated with Icynene spray
foam insulation; airtightness detailing to the roof, with Pro Clima Intello membrane under internal battening.