Civil Engineering Reference
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afforded by people on relatively low incomes. This contrast between public policy
and actual building practice highlights the challenge that governments face in
supporting sustainable construction.
To compound the government's frustration, resource efficient, environmentally
friendly housing is by no means 'rocket science' - indeed, technically it can be
achieved by most contractors. Take energy efficiency as an example: all that is
needed is greater levels of insulation, the careful sealing of all joints, the positioning
of windows to make the most of sunlight, and use of a heat exchange system that
permits the air going out to preheat the air coming in. Most volume developers,
however, have been reluctant to adopt such energy efficient measures because of
the extra cost (and care) involved. They claim that energy efficiency comes at a cost
that cannot be passed onto the consumer. Of course, house builders are private
companies whose purpose is to make money for their shareholders, they are not
green charities with a mission to promote sustainable construction. Few economists
were surprised to note that significantly fewer houses, of any description, were built
in the UK in 2010 and 2011 but the profits of the big ten volume builders greatly
increased (see Gardiner 2012).
Zero-energy or carbon neutral buildings, where energy is provided from
renewable sources (such as solar, wind, geothermal, biomass, or a combination
of these sources) supplied into highly insulated and tightly sealed units, are
commercially achievable. In fact, several low energy and zero carbon projects
have been built in the last few years or are currently in development; 15 prime
examples from 15 different countries across the developed world were reviewed
in 2010 by the National House Building Council. This review not only showcased
the current state of the art, but it also highlighted in global terms how slow these
exceptional developments have been to evolve. In most cases the developments are
small, typically around 40 units, and some are no more than one-off demonstration
projects (NHBC 2010). By the end of 2011, there had only been 128 units
completed to precise zero carbon standards in the United Kingdom, and a further
209 units at code level 5 - a slightly less demanding standard (DCLG 2012). This
poor record is despite the fact that the UK government has been working since 2006
towards a target for all new homes to be carbon neutral by 2016. As this date comes
closer on the horizon, the government has begun to back pedal and redefine its
interpretation of zero carbon.
The approach is only slightly more advanced in the rest of Europe. The
Passivhaus
(passive house) movement has gained some momentum, but it is still
an exception rather than the rule. A preference is slowly emerging for high-quality,
well-insulated buildings that require relatively small amounts of energy for space
heating, but they do not yet dominate the output. Although there are currently
thousands of passive houses in Europe, mainly in Germany, Austria, Denmark and
Switzerland - it is estimated that there are in the region of 25,000 to 30,000 homes
built to this standard - this only represents something like 0.04 per cent of the
related stock (NHBC 2010).
The five basic principles of sustainable housing are shown in
Table 9.3
. If
developments of this type became commonplace in the property market, we
