Desert Mass
A Prototype ADU for Tempe’s Hot-Arid Climate
With Sydney Tucker
Tempe ADU Design Competition
One of 5 winning designs selected to be adopted as a Standard Plan ADU by the city.
Desert Mass is a prototype accessory dwelling unit (ADU) designed to leverage the environmental patterns of Tempe’s hot-arid climate. Instead of resisting the intense heat and dramatic temperature swings with mechanical systems, the project employs mass walls to moderate thermal comfort.
The design uses three L-shaped cores constructed from concrete masonry units (CMU). These cores, in combination with a concrete floor slab and roof, surround the ADU with a dense layer of thermal mass. These mass elements help counteract temperature fluctuations by absorbing solar heat during the day and delaying its transmission to the indoor spaces until nighttime. The lower evening temperatures of the Sonoran Desert balance out the released
heat, reducing the dependency on active cooling systems.
This thermal exchange also works in reverse during cooler months. Solar energy collected during the day is stored in the thermal mass and slowly released after sunset, helping maintain warmth through the night. In both summer and winter, Desert Mass reduces reliance on mechanical conditioning and provides a more stable and comfortable indoor environment.
