In 2008 Deerns became a member of USGBC and is thus authorised to certify buildings according to LEED. 

In 1998, the U.S Green Building Council (USGBC) established the ‘Leadership in Energy and Environmental Design building assessment system for new construction’, or LEED-NC. In the US this voluntarily applied system is accepted as the national standard to assess the energy performance, durability and sustainability of buildings. Buildings can be categorised in one of four categories: Platinum, Gold, Silver and Certified.

Besides certification, Deerns can also give advice during the design stage of a building to target a particular LEED rating.