A related factor may be that LEED does not allow designers to easily forecast energy savings of newer, or less understood, technologies.
A case in point is NRG Insulated Block,which consistently delivers HVAC energy savings of over 60%, by creating insulated thermal mass. In talking to architects and engineers, it is apparent that many are not familiar with the Thermal Time Constant as a measure of a building’s thermal performance. Instead, they look to R-Value and thermal mass.

An ICF wall can have high thermal mass, and high R value, but an ICF wall has isolated thermal mass, meaning that the insulation negates the benfits of the thermal mass.

When forecasting performance, an ICF wall and an NRG wall may have a similar R-value, but the Thermal Time Constant of the NRG wall is much higher, because of NRG’s insulated thermal mass.

NRG measures its performance by comparing US Department of Energy Commercial Building Energy Consumption Survey figures(real numbers), with self-reported utility bills (also the source for US DOE CBEC numbers),so that energy intesity per sq ft is compared.

Even though the HVAC energy savings are consistently above 60% over the CBEC numbers, engineers and architects have to forecast, based not on CBEC numbers, but on an individual energy model that may not deliver as accurate a picture of energy savings provided by insulated thermal mass.

This results in specifying less energy efficient systems that “look good on paper”, but are not as energy efficient, or sustainable, in reality.

Even net zero buildings can be made more sustainable and efficient by implementing solutions like NRG’s insulated thermal mass, but present energy forecasting models do not recognize that value.