It is typically much more expensive to dig down than build on the surface, and in the Phoenix area ground temps are still very warm. A well insulated building o

It is typically much more expensive to dig down than build on the surface, and in the Phoenix area ground temps are still very warm. A well insulated building on the surface will be easier to build, maintain, and won’t require significantly more energy to keep cool. (And with a data center, the majority of the heat is coming from inside the facility, not the environment outside.)