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BCD SPECIAL REPORT ON
HERITAGE RETROFIT
FIRST ANNUAL EDITION
conservation dividend. As well as the
mansion becoming self-sufficient in
heat, the new woodland being planted
to secure future fuel helped reinstate
lost design features from the Grade II
listed park and gardens. The more
actively managed woodlands are also
helping to create larger, better habitats
and improve nature conservation.
Following the success of these
schemes and the experience gained, the
ten-year REI programme was launched
with the expectation that it would
enable the trust save up to £4 million
on its energy costs each year. Electricity
generated from some of the projects will
be sold to the grid providing a new source
of income.
The trust is investing in more than 40
further projects which include:
• a 200kW lake source heating project
on the Blickling Estate in Norfolk,
which will remove two oil tanks and
25,572 litres a year of oil consumption
with an estimated saving of 68 tonnes
of CO₂ per year
• two biomass boilers at Upton House
in Warwickshire to heat the mansion
and other areas, saving an estimated
55 tonnes of CO₂ per year
• a 250kW hydro scheme at Hayeswater
in Cumbria where there is a legacy of
hydropower from historic corn mills
and water wheels – this project will
provide an income stream to support
conservation work on land the trust
cares for.
As well as generating and using
renewable energy, the trust has set about
implementing high energy efficiency
standards in all buildings and operations.
This is being achieved by increasing
standards of insulation and draught
proofing, using water-saving devices and
smart meters, fitting double or secondary
glazing, using thermostatic heating
controls, and installing energy-efficient
equipment and lighting.
Many of the properties in the trust’s
care are energy intensive and in remote
areas without access to mains gas. So
far, the trust has fitted over 60 of its
properties with renewable heating
systems tailored to the needs of each
property. Ultimately, the overriding goal is
to switch to sustainable forms of energy to
reduce reliance on fossil fuels.
HEAT PUMPS
The REI Programme has achieved results
by fitting both biomass appliances
and heat pumps, depending on which
technology suits the individual site. At
Plas Newydd, on the Menai Strait in
North Wales, a 300kW marine source
heat pump fitted the conservation heating
needs of the property. And at Blickling
Hall in Norfolk, the trust has nearly
finished installing a 200kW lake source
heat pump to heat the main hall.
At more isolated, rural properties
such as Blickling, getting the right
electrical load on site can prove
challenging. Prior to installation of
the heat pump, the system was already
operating at the capacity of its electrical
load so a system upgrade was required.
This can be challenging, particularly if the
electricity distribution network operator
(DNO) needs to upgrade the invertors,
cabling and/or transformers required to
power the heat pump. The DNO often
has its own operational constraints and
challenges. It is also expensive because the
technology and materials are complex and
use a significant amount of copper, and
the costs incurred by the DNO must be
met by the developer.
When considering whether a lake is
suitable for a water source heat pump,
distance from the property is important
both in terms of cost for civil engineering
and pipework, and for heat losses in
pumping a longer distance. The relative
elevation of the property and the water
will be relevant too because more energy
is required to pump uphill.
The volume of water in the lake,
its depth and the flow rate of water
refreshing it impact on how much heat
can be generated without significantly
altering the overall temperature. How
much energy the heat pump needs to take
out will depend on the size and heating
requirements of the building it is being
used to heat. Crucially, the sensitivity
of the ecology in the lake or river to
temperature change and to disturbance
caused by the installation of collectors has
to be taken into consideration.
The trust has to select lake sites
for extracting heat carefully to ensure
that the area, depth and flow rate
can be maintained over the course
of the year. Many trust lakes are
spring-fed, ensuring that the ‘fuel
source’ is replenished constantly.
Independent studies by SEACAMS,
a marine science research scheme, have
shown that disruption to biodiversity
can also occur during construction.
Mitigation measures need to be carefully
considered and incorporated in a method
statement agreed with the Environment
Agency and other statutory bodies as
necessary (such as planning and heritage
authorities where archaeological sites are
involved). It is important to keep these
bodies fully engaged during the design
stage of the project.
Sometimes the trust also faces
challenges around the sensitive
archaeological nature of its sites. It is
Used to heat the property and for cooking, the wood pellet range cooker trialled at Hafod y Llan in Snowdonia
reduced fuel costs considerably and demonstrated that wood pellet ranges are a viable alternative to the
oil‑fired models used in many similar properties.