The World in 2030

144 The World in 2030
Germany the air tightness standard – which determines
how leaky a house is allowed to be – is three
times as stringent as the standard in Britain. The ‘Passivhaus’
(passive house with zero carbon emissions)
was first developed in Germany in the late 1980s.
There is nothing magical about these constructions,
and they rely on little in the way of innovative technology.
The builders need only ensure that the ‘envelope’
of the house – the bit that keeps weather out – is
as airtight as possible and contains no ‘thermal bridges’.
A thermal bridge is a material that conducts heat
easily from the inside of the house to the outside. At
every point – even where the wall meets the ground
or the roof – contact with outside temperatures must
be interrupted with insulating materials. 282
Governments are, of course, moving rapidly to introduce
legislation which lays down energy efficiency standards
for new home construction and in Germany legislators are
preparing to introduce an ‘Energy Passport’ 283 which will
guarantee the energy efficiency of private homes. In the UK
the government has introduced Home Information Packs 284
which force property sellers to include an energy efficiency
audit of their homes for the benefit of prospective buyers.
But legislation and good intentions on their own are
not enough. In ‘Heat’, George Monbiot cites the Energy
Savings Trust and Energy Efficiency Partnership for
Homes who say that a large percentage of new buildings
constructed in the UK do not meet the energy efficiency
ratings required by law: