Although this is one of the independent BPR systems for green buildings, LEED system has been
used most widely since LEED buildings are known to be efficient in terms of energy and water
consumption. However, Scofield (2009) claimed that there was no evidence that LEED
certification collectively lowered either site or source energy for office buildings after comparing
energy consumption between LEED buildings and CBECS buildings. Keil (2008) stated that LEED
became expensive, slow, confusing and unwieldy and seemed to focus on points, not
environmental nor financial benefits.
For example, having a few hundred-dollar bike racks and a multimillion-dollar low energy air
conditioning system both get one point. In addition, basic certification (LEED-certified level) is
too low a hurdle to merit the green stamp of approval. In addition, energy and water reductions
cannot be reflected accurately. Furthermore, each of building performance rating systems
provides different assigned points to evaluating categories, such as energy, environment, IAQ
and social aspect. It can cause that the building archives certainly different results on building
performance evaluated by another BPR system, thus it makes users confused whether theirs
buildings are really sustainable.
Although there have been several studies to estimate the benefit and cost for the LEED-certified
buildings, few studies were conducted on the correlation between the earned points from the
system of LEED certification and incremental investments due to lack of related information and
data. Therefore, several studies have been performed on the life cycle costs analysis for LEED
buildings.
In the perspective of life cycle assessment (LCA), LEED system is sufficient to assess the building
performance. However, there are several questions whether LEED-certified buildings are more
cost-effective than the conventional building. According to Menassa (2011), four of eleven LEED
projects had lower electricity consumption savings than their counterpart non-LEED-certified
buildings and other LEED-certified buildings did not meet the expected savings of over 30%.
Therefore, it is necessary to check the incremental investment versus savings of green building
achieving LEED certification when the decision is made on whether the incremental investment
is appropriate depending on the level of LEED.
In order to assess the cost effectiveness for LEED-certified buildings, the integrated LCA and life
cycle cost assessment (LCCA) were used to reflect environmental impacts to life cycle costs in
the estimation of social costs. Recently, an integrated LCA and LCCA approach has been
employed to consider user cost and environmental impact cost. Chan et al. (2008) discussed
that an integrated LCA and LCCA method should be employed for a road construction project
when evaluating infrastructure sustainability, alternative materials, and designs using
environmental, economic, and social indicators.