Shrinking the Footprint
||Photo-voltaic panels on the south aisle roof of St Denys’ Church, Sleaford
(Photo: Julian Patrick)
The institutional footprint of
the Church of England is estimated to
be around one third of a million tonnes
of carbon dioxide for its churches, cathedrals
and offices. This rises to around 1.1 million
tonnes if its 4,700 church schools are included:
equal to that of some leading supermarket
chains. However, its estate includes around
13,000 listed places of worship, 65 per cent
of which include structural elements that
date from medieval times. Making these
historic buildings more environmentally
friendly, particularly when it comes to
heating, has proved a challenge, albeit one
that many congregations are now embracing
as part of their Christian commitment to
the sustainable use of natural resources.
New energy saving information and
advice for the Church of England’s churches,
cathedrals, schools and clergy homes is now
available at www.shrinkingthefootprint.org,
the church’s national environmental campaign.
The information resource is part of the Carbon
Management Programme (CMP), which
was designed for the Church of England by
AECOM on behalf of the Carbon Trust. The
CMP report shows that by using energy more
efficiently in cathedrals and church buildings,
this footprint could be reduced by as much
as 20 per cent. Suggested measures include:
- modernising heating and lighting (see James Morse's article on low carbon lighting also from Historic Churches 2009)
- adjusting time switches and thermostats
- installing or improving insulation and
The table below, taken from the CMP
report, shows the energy saving actions
that a church can undertake and the
potential savings that might be achieved.
Many carbon saving initiatives are already
under way across the country and it is estimated
that the church’s footprint when next calculated
will have been considerably reduced. Some
of the most significant reductions are being
achieved through improvements in heating.
Description of action
Capital cost £
Typical energy saving
as % of annual heating,
electric or total bill
Typical annual cost-saving
or electrical bill
Implement an energy
Low or no cost
Improve boiler controls
Insulate hot water pipes
£10-£30 per metre
Install draught proofing
Reduce heat loss associated
Replace lighting installation
£<100 to £4,000
Installing or improving boiler controls
can reduce energy use by 5-25 per cent
per year, and all churches are being
encouraged to consult a professional boiler
or heating engineer at the next service.
- New boilers typically achieve efficiencies of
80 per cent, condensing gas and oil boilers
can exceed 90 per cent.
- A boiler which is more than 15 years old is
unlikely to be very efficient.
- If the boiler needs constant attention, it
may be more cost effective to replace it with
a high efficiency boiler than to continue
When renewing a boiler, churches are advised
to obtain quotations from three engineers.
Quotations should provide information on the size and efficiency of the new boiler, details of
the boiler controls and thermostatic controls,
warranty and potential servicing costs, and
details of how the contractor has tried to
reduce the energy consumption required.
Heating the church to the correct
temperature can protect against damp as
well as reducing energy wastage. Where a
church is in frequent use, it may be more
efficient to keep the church heated to a low
temperature of perhaps 8-10°C, and increase
to 16-18°C when it is due to be occupied.
Installing zone control valves to reduce
the heat used in unoccupied areas can produce
savings of 5-10 per cent. This is of particular
use to large centrally heated sites with
different areas used at different times, such
as churches with halls or offices attached.
Hot water pipes, including valves and
joints Insulating pipes can reduce heat
energy loss from the pipe by 70 per cent.
This can save around five per cent of the
heating bill, depending on the pipe length
involved. Insulation will cost between £10
and £40 per metre including labour.
Roofs, walls or floors Insulating the
envelope of a building can reduce heat energy
loss by 70 per cent. However, insulating
historic churches may not be practical or
appropriate. Churches built after 1930 will
probably be easier to insulate, particularly
where they have low ceilings and cavity walls.
Professional advice should always be sought
before undertaking insulation work in any
building, as warm moist air which passes
through the material or around it will condense
on cold surfaces beyond. In roofs this can
cause localised damp and severe decay.
Window insulation measure
None (single glazing only)
Single glazing with
Single glazing with
Double glazing with
low emissivity glass
|* The lower the figure, the higher its insulation value
Glazing Single glazed windows transfer
heat from surface to surface well, leading to heat
loss and condensation. Rattling panes and gaps
in frames cause draughts and damp air adds to
the chill, particularly in the winter. Obviously,
the tall leaded lights and stained glass
windows of a typical parish church do not lend
themselves to any form of insulation, but they
should be properly maintained. Furthermore,
ecclesiastical buildings come in all shapes and
sizes: many church halls have windows that are
suitable for insulated blinds and shutters which
may be closed at night, or secondary glazing.
Draught proofing will reduce much of the heat
loss. Some windows may also be suitable for
double glazing. The table above illustrates
the effectiveness of different measures.
The use of double glazing or secondary
glazing will be inappropriate for most historic
buildings. As well as their aesthetic impact
and, in the case of double glazing, the need
to fundamentally change historic fabric,
they also have a high cost relative to the low
energy savings produced. English Heritage
provides guidance on this and other ways of
saving energy in historic buildings at www.climatechangeandyourhome.org.uk.
The sources of renewable energy most likely
to be of use for heating churches are bio-fuels,
ground source heat pumps, or solar power
captured using photovoltaic cells (PV).
Wood chip and wood pellet boilers generally
take up more space than conventional boilers
because the fuel is fed into the furnace
automatically from an overhead hopper,
and because a dry store is required for the
fuel, preferably next to the boiler. A new
room is usually required. The running cost
of burning locally-sourced timber pellets is
generally similar to the cost of burning oil.
At St Paul’s, Gulworthy, a 19th
century Grade II listed building in Exeter
Diocese, the parochial church council
(PCC) recently installed a new wood-fired
boiler in a purpose-built shed outside
the church at a cost of £27,000.
A ground-source heat pump relies on the
same principles as a fridge but with the
cooling pipes placed underground where they
extract heat from their surroundings. Laying
the pipes in trenches is less expensive than
running them vertically through deep bore
holes, but where a burial ground surrounds
the church, this is often the only option.
A ground source heat pump was used at
St Mary’s, Welwyn, a Grade II listed church
in St Albans Diocese, where a well-insulated
extension has recently been added. For most of
the year, both church and extension are heated
by ground source heat pumps topped up with
gas heating if required. Three electrically driven
heat pumps (operating on a green energy tariff)
are connected to a system of pipes drilled into
the churchyard to collect ground heat. This is
compressed to a higher temperature and used
to heat the church buildings. For every unit of
electricity used by the heat pumps, the church
gets around three units of heat. It is estimated
that this one church will avoid releasing
around 30 tonnes of carbon dioxide per year.
The installation cost around £50,000
and initial results are in line with the
performance predictions. Real-time
information is available on the church’s
website at www.gshp.welwyn.org.uk.
Photovoltaic solar panels
Solar panels need to be oriented towards the
sun. As churches are conventionally oriented
east-west, their south-facing roof slopes are
perfect for collecting solar energy. St Denys’
Church, Sleaford in Lincoln Diocese is a
12th-century Grade I listed building which
now has 56 solar photovoltaic panels installed.
The project began after the PCC was inspired
by panels on St James’s Church, Piccadilly,
London. Advice was sought from the Diocesan
Advisory Committee for the Care of Churches
and from English Heritage; both specified that
any panels must not detract from the visual
appearance of the church, nor must any damage
be done to the fabric during installation.
Since the south aisle roof at St Denys’ is
hidden from ground level by a 900mm parapet,
the location seemed ideal. Unfortunately, initial
advice suggested that to achieve maximum
efficiency the panels would need to be tilted
at an angle of between 30 and 40 degrees,
which would have rendered the panels visible
over the top of the parapet. However, by
laying the panels flat on the south aisle roof
only four per cent efficiency was lost.
The problem of how to fix the panels to
the traditional lead roll roof remained. Similar
installations where solar panels could not be
attached directly to the building had involved
securing the panels to large plastic boxes filled
with ballast. The disadvantage of this system
lies in the height and weight of the boxes.
A structural engineer was engaged
and a detailed brief was prepared and
agreed. The PCC then invited installation
companies to quote for the project and a
local contractor, Julian Patrick of Freewatt
Ltd, came up with a solution involving the
newly developed ‘Solstice’ clamps. These
allowed the panels to be fitted on a lightweight
frame no more than 300mm high, which
also meant that more panels could be fitted
as no ballast weight was involved and the
panels could be placed closer together.
The final plan was presented to the
DAC and English Heritage, and both North
Kesteven District Council and Sleaford
Town Council were consulted on the
visibility issue. The project, which cost
around £56,000, was mainly grant funded.
Every place of worship is unique,
and there is no single solution to energy
reduction. It is best to start small by reducing
energy wastage. Where improvements are
proposed, seek the best advice available.
Historic Churches, 2009
RACHEL HARDEN (firstname.lastname@example.org) is a senior communications officer of
the Church of England’s Archbishops’ Council.
Shrinking the Footprint is a CofE campaign run by
the Cathedral and Church Buildings and Mission
and Public Affairs Divisions of the Archbishops’
Council, working closely with dioceses.
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