The University of Arizona says that the U.S. Green Building Council has awarded two new residence halls with LEED platinum certification—the highest category of recognition for environmentally friendly design and construction.

Árbol de la Vida (Tree of Life) and Likins residence halls opened in 2011 on the Tucson campus. Árbol de la Vida has about 720 residents, and Likins has about 370. Each of the halls has roof-mounted solar panels to provide a portion of the facilities’ hot-water needs; low-flow bathroom fixtures and dual-flush toilets to conserve water; occupancy sensors to adjust thermostats when rooms are not occupied; and awnings on the south side to maximize sunlight in the winter and block it in the summer.

The buildings were constructed with recycled and local materials. Students use software on the Web to monitor the buildings’ energy usage.