LEED vs cost and energy

Over the past few years there have been discussions about green construction and making buildings more efficient.  Leadership in Energy and Environmental Design (LEED) was devised to keep track and rate how efficient a building is. When LEED came out in 1998, many people were not sure and questioned whether this new way of building would actually work.  The best economical way to see how much energy a building will use is to model it on a computer.  The accuracy of modeling energy consumption can vary depending on the level of detail.  The more detail the more expensive it will be and depending on which software is used it may not be as accurate as one might think.  Looking at the image below, we can also see that LEED buildings pretty much all group together. There are a few that perform better than expected and a few worse, but majority are 20-30% efficient.

vic4

An article by John H. Scofield looked into seeing if LEED buildings actually do save a significant energy.  In a simple answer, “not really.”  The majority of LEED-certified offices are using less energy than their comparable non-LEED offices, but they only contribute about 10%. A small handful of big buildings contribute a lot more. This can be seen in the graph below. Big buildings account for majority of the consumption and smaller LEED buildings do little to curve the energy consumption.

leed-vs-cost

LEED is also full of regulations that can at time hurt and but restrictions on a project. A new residence hall at Carnegie Mellon University was built as LEED silver and everything was documented to see if it was worth it. At the end:

  • Cost $347,118 more (3% extra in construction cost)
    • 12% of the budget was spent on recycled material  and  9% on sustainable site
    • Larges  increase cost was forced air ventilation ($100,000)
    • Commissioning cost ($65,000)
    • Labor spent on compiling LEED data ($61,000)
  • 20.3% more energy efficient compared to similar residence hall, but uses 12% more energy compared to residence hall with heat recovery system. This increase in energy costs due to:
    • Required greater fresh outdoor air ventilation
    • Resulted in greater heating and cooling loads as well larger electrical fans
    • Green power costs more (LEED green power contract)

    case study 1

LEED seems like it is in the right direction, but with all of its regulations it seems to be doing more harm than good. LEED keeps being updated with new regulations, but these regulations are just being broadened to encompass more topics. LEED covers too many topics from site sustainability to construction, but energy only accounts for one small section. Parts of LEED seem to be working and other parts need to be looked at more closely. LEED needs to be cut back a bit and get revised to focus on more critical areas.

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