Schools and education facilities supplement Refurbishment
Refurbishment of older
schools is important to cutting
emissions from the sector.
switches and user engagement can assist with this.
Otherwise, lighting energy consumption can be reduced
by improving the efficacy of lighting systems, and by
incorporating better controls. Full lighting replacements
will pay back within the system lifetime, though often
require high capital investment. Where undertaken,
the installed lighting load should not exceed 2.67 W/sq
per 100 lux. A cheaper alternative could be to retrofit
T5 conversion kits to existing T12 fi ttings (or T8 fi ttings,
though energy savings are typically small). These could
pay back in about four years, although care must be taken
to ensure illuminance does not drop to unacceptable levels.
Fitting automatic lighting controls (either occupancy or
daylight-linked, depending on the situation) can pay back
in fi ve years, and should be considered where 500 kWh of
“Appropriate
controls and optimisers should all have paybacks well under electricity can be saved a year.
effi ciency
fi ve years. Where orientation or occupancy patterns vary • Measurement: High-energy users within the school, such
widely across a building, fi tting zone controls, provided as IT and catering services, should be identifi ed through
measures can
the existing pipework arrangement allows for this, can measurement and surveys, and appropriate solutions
provide real
payback in around three years. TRVs could also achieve specifi ed following a process that compares the various
paybacks”
good paybacks, and both of these control options should options available. The schools should be involved in this
also improve occupant comfort. Feedback should be process, and indeed energy management and surveys
sought from occupants, and the system settings adapted represent a good opportunity for integration within the
accordingly. Providing local water heating can make good curriculum.
sense for larger schools with centralised hot water provision As the above analysis shows, appropriate energy
where there are long pipe runs. In all cases, main heating efficiency measures can indeed work well in existing
pipework and DHW pipework should be insulated (payback schools, when applied appropriately, with real and
under two years). In addition, boilers should be serviced identifi able paybacks. So the major goal of making not
annually (or every six months for oil installations). just new schools but existing ones highly energy effi cient
• Heat loss: Walls account for 10 to 30 per cent of total need not be that elusive. ●
heat loss. Cavity wall insulation can reduce this by two-
thirds, with payback in about six years. Where the wall Dan Lash is a CIBSE Low Carbon Consultant and
construction is solid, insulation to one face can be applied, a Research Fellow at the Centre for Energy and the
though this is a disruptive measure, and will either result Environment, University of Exeter. www.ex.ac.uk/cee
in a change of building appearance (external insulation) CIBSE Guide F and TM46 are available from www.cibse.org/
or a loss of fl oor space (internal insulation). Both options publications
have long paybacks, though the marginal cost of adding
insulation during major refurbishment where a structural
100 100%
element is stripped back is well worth pursuing.
90 90%
Similarly, retrofi tting insulation to uninsulated pitched
80 80%
roofs with easy access is a very cost-effective measure. For
fl at roofs or where roof spaces are occupied, this is usually 70 70%
only cost effective at the time of more major alterations/
60 60%
replacements. Replacing old ineffi cient glazing with new
double or triple-glazing purely to save energy has long 50 50%
paybacks, though can improve local comfort for occupants.
40 40%
Draft-proofi ng is a relatively cheap and easy DIY measure
and is likely to pay back in less than fi ve years.
30 30%
Although mechanically ventilated schools are less
20 20%
common, fi tting heat recovery to HVAC systems can pay
back in fi ve years for plant running for 40 hours a week
10 10%
and paybacks of less than a year can be achieved by fi tting
0 0%
CO2 sensors to occupied spaces if the ventilation rate can
050 100 150 200 250 300 350 400 450 more
be adjusted accordingly. Energy savings realised from
Pre-Frequency Post-Frequency kgCO2/head
the above measures can easily be undone if windows are
unnecessarily left open when spaces are unoccupied, or if
Pre-Cumulative% Post-Cumulative%
energy savings are spent on increased comfort. Degree day corrected carbon emissions (kgCO2/head) due to heating for a number
• Lighting: This can account for 20 per cent of total energy, of schools (primary y-axis) that were 50 to 80 per cent refurbished. The cumulative
and often savings can be made instantly by turning off frequency curves before (red) and after (green) refurbishment are also displayed
artifi cial lighting when it is not required. Well-labelled (secondary y-axis). Source: AECOM
www.cibsejournal.com February 2010 CIBSE Journal 31
CIBSEfeb10_School_pp30-31_refurb.indd 31 25/1/10 15:44:58
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