Energy conservation and efficiencyin buildings 281of the total use of energy is in buildings (about two-thirds of this in
electricity), including about twenty per cent for their heating (including
water heating) and about three per cent for cooling.^13 Energy demand
in the buildings sector grew by about three per cent per year averaged
worldwide from 1970 to 1990 and, apart from countries with economies
in transition, has been growing during the last decade by about 2.5% per
year. How can these trends be reversed?
Substantial energy savings can be made in buildings by improving
their insulation (see box above) and by improving the efficiency of appli-
ances (see box on page 279). Many countries, including the UK and the
USA, still have relatively poor standards of building insulationcompared,
for instance, with Scandanavian countries. Improvements in building de-
sign to make better use of energy from sunlight can also help (see box
on page 301). There are also large possibilitiesfor the improvement of
the efficiency of appliances at relatively small cost.
The results of a study in the USA have identified some of the large
savings that could be made in the electricity used in buildings. The
cost of such action would be less than the cost of the energy savings;
overall therefore there would be a substantial net saving (Figure 11.8).
The twelve options in Figure 11.8 together cover about forty-five per
cent of the amount of electricity used in residential buildings in the
USA, which in 1990 was about 1700 TWh or about ten per cent of
the USA’s total energy use. The four options that provide the largest
savings (together adding up to sixty per cent of the savings) are in the
areas of commercial lighting, commercial air conditioning, residential
appliances and residential space heating. Electricity companies in
some parts of the USA are contracting to implement some of these
energy-saving measures as an alternative to the installation of new
capacity – at significant profit both to the companies and its customers.
Similar savings would be possible in other developed countries. Major
savings at least as large in percentage terms could also be made in
countries with economies in transition and in developing countries if
existing plant and equipment were usedmore efficiently.
Further large savings can be realised when buildings are being
planned and designed by the employment ofintegrated building design.
When buildings are designed, the designsof the systems for heating, air
conditioning and ventilation are commonly carried out separately from
the main design. The value of integrated building design is that energy-
saving opportunities can be taken up associated with the synergies be-
tween many aspects of the overall design and the design (including the
sizing) of the systems where much of the energy use occurs. Many ex-
amples exist of low energy buildings, where integrated building design
has been employed, that consume less than half the energy and are often