Hello, WFH equesters!

I would appreciate any insight on modeling underground surfaces from anyone that has tried modeling continuous insulation as is common on Passive House projects, especially in radiant slab heating applications.

I want to compare alternative thicknesses for continuous horizontal underslab insulation for both radiant slab heating and non-heated slab applications. Continuous underground insulation is becoming more common, particularly in Passive House projects or from passive-house-inspired architects. DOE-2.2 and 2.3 emphasize slab edge effects in the documentation and seem to ignore potential heat transfer from surfaces that have a path of travel greater than 4' between the surface and ambient air conditions. The wizards have only one option in the dropdown menu for continuous slab insulation - R10 continuous. Any underground slabs that have no exposed perimeter are given an R-100 insulation layer that results in near-zero heat transfer in the simulation.

All tips, musings and even non-sequiturs will (likely) be appreciated.

~Bill

William Bishop, PE, BEMP, BEAP, CEM, LEED AP
Senior Energy Engineer

T: (585) 698-1956 F: (585) 325-6005
bbishop at pathfinder-ea.com www.pathfinder-ea.com
134 South Fitzhugh Street
Rochester, NY 14608