Passive Solar Home with Soil Heat Storage

Josh built this very unique passive solar home in Missouri. The house incorporates the usual south glazing to gather solar heat and good insulation to reduce heating requirements.  But, it also has a unique heat storage capability using the soil under the main floor.  And, a unique cooling system that makes use of the same soil heat store.

Passive solar home with heat storage

The south face of Josh's solar home.


Thanks very much to Josh for taking the time to provide the details on this unique design.




The most unique feature of the house is that it stores excess solar heat during the daytime in a two foot thick soil bank below the floor slab.  This will allow Josh to reduce the overheating problem that passive solar homes sometimes have during the daytime, and to store heat in the soil that can then be used overnight, or even to cover heating needs for some days with no sun.

The house is well insulated using ICF (Insulated Concrete Forms) for the main part of the house, rigid polyiso for the roof, and cellulose for other parts. 

The house also has pex piping embedded in the underfloor heat store, and Josh plans to pipe 62F well water through the piping to cool the heat storage and provide "coolth" for cooling the house in the summer.  A very nice dual usage of the heat store.

soil heat storage ducting

Ducts to distribute solar heat to the below floor heat store.


pex piping in floor

Pex tubing in floor for radiant heating (and for well water cooling in summer).

This pdf provides all the details on the Josh's design (and life) philosophy and construction...

Josh promises an update on the performance of the house once he has lived in the house for a while.


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