The emerging technology of wireless sensing shows promise for changing the way sensors are used in buildings. Lower cost, easier to install, sensing devices that require no connections by wires will potentially usher in an age in which ubiquitous sensors will provide the data required to cost-effectively operate, manage, and maintain commercial buildings at peak performance. This chapter provides an introduction to wireless sensing technology, its potential applications in buildings, three practical examples of tests in real buildings, estimates of impacts on energy consumption, discussions of costs and practical issues in implementation, and some ideas on applications likely in the near future.