Environmental Engineering Reference
In-Depth Information
Table
.
Primary energy use in buildings
Residential
Commercial
Space heating
%
Lighting
%
Space cooling
%
Space heating
%
Water heating
%
Space cooling
%
Lighting
%
Water heating
%
Refrigeration
%
Electronics
%
Electronics
%
Ventilation
%
Cooking
%
Refrigeration
%
Wet cleaning
%
Computers
%
Computers
%
Cooking
%
Other
%
Other
%
Total energy (Quads)
.
Total energy (Quads)
.
does today. The projection of a
% increase in energy
use really only says that ef
ciency remains about the same
over the next
years. Since the stock of buildings grows
by about
.
% per year and we look
years into the
future we should expect to use about
% more energy if
we continue as we are. If we can improve overall ef
ciency
by
% per year to match the growth we can achieve zero
growth in this sector, and we should be able to do better
than that. To improve building ef
.
ciency it is useful to
start by understanding how energy is used, and it is used
somewhat differently in the commercial and residential
sectors.
Table
.
shows the top uses for each sector
(from the
Energy Data Book of the DOE).
As of
, in the United States there were
million
residences totaling
billion square feet (houses, apart-
ments, and trailers), and
billion square feet of commer-
cial space. The top four energy consumers are the same in
the residential and commercial sectors and between them
