The problem
with windows
gy Solutions
The very essence of windows –
Ener
they let us see clearly through
– is also at the root of their
problem. Because windows let
everything through: heat, cold
and glare.
People responsible for windows are
inevitably aware of the problems of heat
loss in winter – but what is often
overlooked is the cost of windows in
summer. And the cost can be counted in
wasted energy, loss of productivity and in
the welfare of people. directly on someone, the heat feels temperatures rise people switch on fans,
Glass in windows allows about 90% of magnified. People complain – but not cooling devices and turn up air
sunlight to travel straight through causing without reason as research undertaken by conditioning. These are generally
problems with glare on screens and heat Wyon in the USA, albeit a bit dated, found uncontrolled and unmonitored uses of
gain. that productivity in an office environment energy and there are plenty of instances
Dealing with heat gain first, according dropped by 40% at 75°F compared to where they are used unnecessarily or
to the Building Research Establishment 68°F, the most comfortable temperature to simply left on, adding to the organisation’s
(BRE), solar gains in a glazed building can work in. carbon footprint.
account for ten times the heat generated Other research from the USA by Vernon Of course blinds are often pulled which
by equipment or lighting. In one hour a found that accidents are 30% more likely negates the uplifting effect of windows
person gives of about 8W of heat energy to occur at the higher temperature also and ironically this could also result in
per square metre, similar to a computer, because people become fatigued. Glare supplementary lighting being switched on.
whereas a window representing 40% of from the sun falling on monitors is also a The proposition in this article is the heat
wall space on a South facing elevation can problem with 75% of people that work on and glare should be stopped from entering
transmit 63W of heat to a square meter of computers suffering from some kind of the building in the first place. Solar control
floor space. strain. window film is a convenient solution as it
The result is workspaces become What are the energy and carbon can be installed on selective windows with
excessively hot and, where sunlight falls footprint implications of heat gain? As little disruption to activity. And right from
the start it improves the work/study
environment and can show a pay-back in
energy savings.
Modern high-technology window films
are well worth looking at. They have better
solar protection properties than even the
latest glass. New films have been
introduced that can measurably reduce
transmitted heat and glare and yet have
very high levels of visible light
transmission. Gone are the days when
window films looked like ‘mirrors’ and
modern films come in a range of colours
and tints that can enhance a building. The
fact that they last a lot longer also helps.
The main contractor for window film is
Durable Limited which is the OGC Buying
Solutions framework supplier to the public
sector.
This article has focused on summer –
but certain window films also have
insulation properties that reduce up to
30% of heat loss in the winter. Overall
window film is one of the few
improvements that can be made to a
building with minimum disruption, has an
immediate impact of business
performance, is praised by staff and will
eventually pay for itself.
Call Durable on 01189 895200 or visit
www.theproblemwithwindows.co.uk
for more information.
Solar control window film can make a significant difference to internal temperatures
reducing the need for energy consuming cooling devices.
14 energy solutions Building & Facilities Management – April 2008
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