Leadership in Energy and Environmental Design. Originaly a certificaton system for commercial buildings with 4 levels of acheivement; Certified, Silver, Gold or Platinum, since 2004 the system has been used for residential homes. The qualifications and standards are stringent and the costs simply to be tested range from $500 - $3000, but the benefits, particulary for builders seem to perhaps outweight the extra expenses and hassels.

LEED certification and accredition are two things. LEEDS certification is for buildings while accreditio is for personnel

"The Leadership in Energy and Environmental Design (LEED) Green Building Rating System, developed by the U.S. Green Building Council, provides a suite of standards for environmentally sustainable construction. Since its inception in 1998, LEED has grown to encompass over 14,000 projects in 50 US States and 30 countries covering 1.062 billion square feet (99 km²) of development area.[2] The hallmark of LEED is that it is an open and transparent process where the technical criteria proposed by the LEED committees are publicly reviewed for approval by the more than 10,000 membership organizations that currently constitute the USGBC. Individuals recognized for their knowledge of the LEED rating system are permitted to use the LEED Accredited Professional (AP) acronym after their name, indicating they have passed the accreditation exam given by the USGBC." "Different LEED versions have varied scoring systems based on a set of required "prerequisites" and a variety of "credits" in the six major categories listed above. In LEED v2.2 for new construction and major renovations for commercial buildings there are 69 possible points and buildings can qualify for four levels of certification: Certified - 26-32 points Silver - 33-38 points Gold - 39-51 points Platinum - 52-69 points LEED certification is obtained after submitting an application documenting compliance with the requirements of the rating system as well as paying registration and certification fees. Certification is granted solely by the Green Building Council responsible for issuing the LEED system used on the project. Recently the application process for new construction certification has been streamlined electronically, via a set of active PDFs that automates the process of filing the documentation." Source and further information: http://en.wikipedia.org/wiki/Leadership_in_Energy_and_Environmental_Design