Thermal Storage Wall

An exterior solar-glazed thermal storage wall absorbs sunlight (heat) in winter, conducting heat through the wall and releasing it into an adjacent space at night.

A Thermal Storage Wall is a mass wall, usually masonry, located directly behind solar glazing (facing the equator).

Size the wall and solar glazing area as a percentage of the floor area to be heated:

Cold Climates*

• 30% at 28º – 40º latitude

• 40% at 44º – 56º latitude

Temperate Climates**

• 20% at 28º – 40º latitude

• 30% at 44º – 56º latitude

Make the exterior wall surface a dark color, and make the thickness of the wall:

• 30 – 46 cm (12-18 in) for concrete

• 25 – 36 cm (10-14 in) for brick

• 20 – 30 cm (8-12 in) for adobe

*Cold = Winter temp. -6.7ºC to -1.1ºC (20ºF to 30º F); **Temperate = Winter temp. 2.2ºC to 7.2ºC (35ºF to 45º F). When there is a useable space between wall and glazing, and a convective connection to adjacent spaces, the wall can be a medium color. Recommendations are for skin-load dominated buildings.