This idea has been around for a while, and scales both ways.... I know house where where 40 tons of crushed rock were added to a new basement enclosure under a

This idea has been around for a while, and scales both ways.... I know house where where 40 tons of crushed rock were added to a new basement enclosure under a new large south facing sun room, that has fans and a differential controller to pump excess heat into the rock, was built in the 1980's here in Nova Scotia, the house only needs suplimental heat for comfort in the form of a small wood stove.