Hi, everyone,

I've gotten involved in doing a short write-up for the United Nations Environmental
Programme (UNEP) on the energy savings in the building sector due to the implementation of
building energy standards over the past two decades. My thesis is that although the
theoretical energy efficiency of the building stock has improved significantly over this
period, the actual measurable reductions in energy use intensity has been quite small, due
to the following factors - increased amount of plug loads, and improvements in thermal
comfort in lieu of real energy reductions (the so-called "take-back effect" mentioned by
Mark Modera and others). The bottom line is that although one can say that energy use
intensity in refrigerators have gone down by more than 50%, one cannot simply cannot say
the same in either residential or commercial buildings. At the most elementary level, has
anyone documented the change in EUIs in residential and commercial buildings by vintage
based on data bases such as RECS and CBECS for the entire US, or CEUS for California ? On
a more detailed level, does anyone know of studies that estimated the changes in space
conditioning energy use between buildings built before the standards, i.e., 1970's
vintage, and afterwards, i.e., within the last decade?

I'm throwing the net wide here, because I need to get some ballpark numbers by this
Friday. Thanks.

Joe Huang