What is thermal mass anyway? Thermal mass in the solar heating context refers to the capacity of dense materials (concrete, rock etc.) to store significant quantities of heat, at a reasonable rate, as their temperature rises (and then release it as the temperature around them falls). If a regular sheetrock house has a fair amount of south windows it will overheat on sunny winter days and cool down rapidly after sundown. Such large interior temperature swings are unacceptable from a comfort point of view, and a portion of the collected solar heat is unusable and therefore wasted as well.

The remedy for this untenable situation is to add interior thermal mass materials so that interior temperature swings are kept to 10F, say between 65F and 75F. The main functional idea behind deploying thermal mass materials is that they suck up excess solar heat during the day, thus preventing overheating of the house air. Then during the night this heat is slowly released into the rooms. The stored solar heat, you could say, is invited out of storage as the house air tries to cool down.

White Horse Mesa will combine two forms of thermal mass:

1. Geothermal Mass - slow release
2. Structural Mass - rapid release