Interesting paper from the recent CIBSE Technical Symposium looking at the possibilities for a portable wireless sensor network approach to post-occupancy building commissioning:

http://www.cibse.org/content/cibsesymposium2013/paper065.pdf

Addresses many of the well documented issues concerning building energy use in practice and the potential  benefits of a wireless monitoring solution including flexible deployment, temporary usage or as a seasonal commissioning aid.