Warmer Bath

Bath Preservation Trust and the Centre for Sustainable Energy
the importance of taking seriously the full range of
relatively straightforward energy saving measures before
you start spending serious money on more disruptive
measures or renewable technology. There are however,
other things that come into the equation. If you are
planning other home improvements or a full-scale
renovation, your priority should be to ensure that you
take every opportunity to integrate energy-efficiency
measures into your plans.
Energy, money and carbon
Most of the energy we burn in our homes is devoted to
heating: nearly three fifths in an average home (Figure
1) and considerably more in an unimproved traditional
home. This is why energy efficiency measures such as
installing draught-proofing and loft insulation can make
such a big difference to energy consumption and costs.
Heating water accounts for around a quarter of energy
consumption, though this is very dependent on the size
of the household and how carefully water is used. Lights,
appliances and cooking account for less than one fifth of
domestic energy consumption.
As the cost of the energy you use depends on the price
of the fuel, the relatively thin ‘lights and appliances’
slice of the energy pie can turn into a much bigger slice
of your annual energy bills because electricity is so
much more expensive than gas. If you use electricity for
heating as well as power, you will be very familiar with its
high cost.
Electricity is also more ‘carbon intensive’ than gas.
Compared to burning gas at home, using electricity
generates nearly three times the quantity of greenhouse
gases. This is because the generation of electricity in
distant power stations is so inefficient. Over half the
energy is lost in the generation process as waste heat and
even more is lost in the transmission of the electricity.
Figure 1. Domestic energy consumption: average UK home
(Department of Energy and Climate Change, 2010)
lights and
appliances,
16%
cooking, 3%
You can buy electricity on a ‘green’ tariff or from an
exclusive supplier of renewable electricity such as
Good Energy (www.goodenergy.co.uk) or Ecotricity
(www.ecotricity.co.uk). This is easy to do as no physical
changes have to be made to the wires that provide your
electricity. In fact, you will continue to use exactly the
same electricity as you did before but the company will
use your payments to put renewable electricity into the
Grid to match the amount of electricity you consume.
Even if you are buying from a green supplier, you should
do everything you can to reduce your consumption.
Renewable electricity is a scarce and precious resource.
If you waste it, you will prevent others from using it
and force them to use electricity made in coal, gas and
nuclear power stations. As long as renewable energy
remains scarce (the forseeable future), we should use it
with as much care as possible.
Costs and benefits
Your decisions about what to do ought to be informed
by a broad assessment of the costs and benefits of
action. However, there is no ‘magic formula’ for doing this
because many of the possible costs and benefits cannot
be directly compared. Assessing the relative importance
of each of the following is ultimately a matter of
judgement:
Costs
• Financial costs: capital and installation
• Visual impacts (e.g. solar panels)•
• Fabric impacts (e.g. loss or damage to original features
and other historic fabric)
• Impacts on home (e.g. loss of room space due to
internal insulation)
Benefits
• Increased warmth and comfort
• Reduced running costs
• Reduced carbon emissions
• Improved quality of life
• Increased resilience to future fuel price rises
Table 1 gives an overview, for a selection of measures,
of three key issues: cost, carbon cost effectiveness and
disruption. The carbon cost effectiveness is the capital
cost of the measure less the fuel cost savings that it will
deliver, per tonne of carbon dioxide emission saved,
during the lifetime of the measure. Note how poorly
the energy generating options perform on this measure
compared to the energy saving options.
h o t wate r,
24%
heating,
58%
This table, which is ordered by carbon cost-effectiveness,
presents the options in a slightly different order to
the energy hierarchy (page 11). This is partly because
the energy hierarchy takes some account of the
potential impacts of the measures on the look and
fabric of traditional buildings in Bath. Although Table
1 has a ‘disruption’ measure, this is an indication of the
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