THE INFLUENCE OF AMBIENT LIGHTING ON PUPILS IN CLASSROOMS
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Tommy Govén, The influence of ambient lighting on pupils in classrooms
THE INFLUENCE OF AMBIENT LIGHTING ON PUPILS IN CLASSROOMS
– CONSIDERING VISUAL, BIOLOGICAL AND EMOTIONAL ASPECTS -AS WELL AS USE OF ENERGY
Govén, Tommy 1)
Laike, Thorbjörn 2)
Raynham, Peter 3)
Sansal, Eren 4)
ABSTRACT and psycho-physiological effects. Both the
intensity, spectral composition, spatial and
This poster reports the initial findings of a
temporal distribution of the lighting, may be of
yearlong study into the impact of the lit
relevance.
environment on school children. The study is
based on a group of four classrooms in a A major step was taken when in a study on
primary school with children aged eight to nine rat, showed that neither rods nor cones were
years. A total of 56 children divided in four needed to modulate the circadian pacemaker;
classes took part in the study which was instead retinal ganglion cells with the photo
carried out during the school year 2008/2009. pigment called melanopsin innervating the
SCN were intrinsically photosensitive.
All the children attended the same
educational program in the junior school. Two During the last three years several
classrooms served as controls and two convincing studies have shown that the human
classrooms had enhanced lighting. Initial circadian rhythms are affected by these retinal
results have been analyzed and the paper ganglion cells also today mentioned as the
presents findings in terms of energy ‘third receptors’.
consumption, biological* and psychological
Due to the fact that more elaborated
parameters and measures of academic
knowledge about the details of the circadian
performance.
photoreceptors were established, the research
*the biological data are under analysis and will on how specific wavelengths within the light
be added. spectrum affected the physiological responses
rapidly grew. It has been shown that certain
1. INTRODUCTION
wavelengths have peak melatonin suppression
The school is the workplace for both children on humans.
and teachers. Lately there has been a
3. AIMS OF THE STUDY
discussion about the environment in the
school. Signals that children under-perform, One aim of the study was to explore in what
behave in a bad manner and are tired are now way the ambient light may have an impact on
being recognized. One part of the environment the children’s emotional status, achievement
is the physical environment and several and well-being described both subjectively and
studies show that physical environmental physiologically considering both daylight and
factors may have an impact on the artificial light.
abovementioned factors. Lighting conditions is
A second aim was to investigate the
considered as an important part in the physical
behavior in use of controls.
environment.
A third aim was to investigate in which way
This report covers the findings of our study
different lighting control systems affect the use
from October 2008 till March 2009. The study
of energy in classrooms.
is ongoing and full results will be published in
due course. The presentations of results are divided
into different parts according to elements of
2. BACKGROUND
the VBE-model which takes visual, biological
Correlations may exist between the physical and emotional aspects into consideration.
parameters of light and the diverse biological
1
Tommy Govén, The influence of ambient lighting on pupils in classrooms
4. SUBJECTS The achievements between the four
classes were even regarding the grades from
A total of 56 children aged 8-9 years of age
the previous year. They were allocated to their
divided in four classes took part in the study.
classrooms at the beginning of the semester
All the children attended the same educational
by the school authority?
program in the junior school.
Distribution of the children in the four classrooms
Gender C1 E1 C2 E2 Total
Boys 7 7 7 9 30
Girls 7 4 8 7 26
Total 14 11 15 16 56
5. DESIGN OF THE STUDY
Pickhurst Junior School. The
experimental classrooms to
the left, the control rooms to
the right.
The study was carried out in a junior school south. Blinds installed on south facing
located in the south of London. For ethical windows.
reasons the only children taking part in the
In order to have the same light emission in
study were those whose parents provided
all classrooms, the luminaries in the control
positive consent. About 50 % of the children in
classrooms were changed to new luminaires
the school year took part in the study.
equipped with high frequency ballasts. In the
Four classrooms of the same size were four classrooms the luminaries were equipped
investigated. Two experimental classrooms with the same type of tri-phosphor fluorescent
(E1 & E2) were equipped with a new lighting tubes with a colour temperature of 4000 K and
design based on an increased horizontal and a Ra of 80.
ambient light in relation to two control
6. STATISTICS
classrooms. The two control classrooms (C1 &
C2) were equipped with an existing lighting The initial treatments of the data were carried
system based on general lighting. out by one-way analysis of variance with post-
hoc analysis. Also t-tests were applied for
E1 & C1 were situated on ground floor with
some analyses. The further treatment of data
daylight penetration from one side, south. E2
was carried out mainly by means of analysis of
& C2 were situated on the 1st floor with
variance with a repeated measures design.
daylight penetration from two sides, north and
2
Tommy Govén, The influence of ambient lighting on pupils in classrooms
This is a factorial design involving the following 4. The periods of the school year (four
four independent factors; times).
1. General lighting vs. increased general The independent factors, a) to c), were
lighting and increased ambient lighting. tested between subjects as well as their
interaction, while factor d) was tested within
2. Daylight penetration in one direction vs.
subjects.
daylight penetration I two directions.
In most analyses, data were grouped in six
3. Increased ambient lighting vs. increased
blocks corresponding to the six measurement
ambient lighting at a higher amount at
occasions during the school year. SPSS 15.0
certain times of the day (algorithmisch
statistical package was used for the analyses.
scene-setting).
7. DAYLIGHT AVAILABILITY
Daylight factor, DF
Daylight factor
DF, blinds
Daylight factor with blinds
closed on south facing
windows.
There is significantly more daylight available in Moreover, the north facing windows in the top
the top floor classroom (C2 & E2) as they have floor rooms do not have blinds fitted and so
windows on both sides of the room and they when the daylight factor in the rooms never
are less shaded by the trees outside. drops very low.
8. LIGHTING SYSTEMS
Control room Experimental room
3Tommy Govén, The influence of ambient lighting on pupils in classrooms
Surface mounted lighting system with direct Lighting system with a combination of
light distribution in the control classrooms. direct/indirect light distribution in the
experimental rooms.
Illuminance values in the classrooms.
Eh, Average horizontal illuminance
on working plane (lux)
Ev Average vertical illuminance (lux)
Ec Average ceiling illuminance (lux)
Eve Vertical illuminance at eye (lux)
The experimental classrooms (E1 & E2) had a system. In one of the experimental rooms (E2)
general lighting system adjusted to an an algorithmic scene-setting system was
illuminance level at working plane of installed in order to achieve an increased
approximately 500 lux. Luminaires for general illuminance during the first lesson in the
lighting were suspended from the ceiling and morning and the first lesson after lunch each
had a direct/indirect light distribution. school day for the whole school year. The both
Additional wall-washers were installed to control classrooms had a general lighting
achieve an increased ambient light level on system with an illuminance level at working
the walls. plane of approximately 300 lux without any
additional wall-washers. All luminaires were
Furthermore E1 & E2 were equipped with
ceiling mounted. The control classrooms were
an absence detection and daylight control
both manually controlled.
4Tommy Govén, The influence of ambient lighting on pupils in classrooms
9. RESULT
Energy measurements
In order to measure the energy consumption, of the teachers that determine if the lighting is
presence, use of daylight and the use of switched on or off. In room C1 the energy
controls a data-logger were installed at the consumed for the week was 13.7 kWh and in
school. All the parameters were continuously C2 it was 9.5 kWh.
measured over the whole school year.
It is assumed the difference is explained by
Rooms C1 and C2 have manually the greater daylight availability in C2 allowing
controlled lighting and thus it is the preferences the teacher to turn off the lights more often.
5Tommy Govén, The influence of ambient lighting on pupils in classrooms
In room E1 the benefits of the automatic Given that the lighting system in room E1
control system are seen with an energy use of can deliver almost twice the light of the one in
only 10.7 kWh for the week. Whilst E1 has the C1 this is a remarkable result.
same amount of daylight as room C1 the
The use of energy lighting is in average
automatic dimming system ensures that this is
approximately 20% higher during the dark
fully exploited to reduce the power of the
period versus the brighter period of the year.
lighting, also the absence detection system
ensures that the lighting is not on when the
room is empty.
Weekly use of energy (kWh)
Use of energy C1 E1 C2 E2
Typical week commencing November/December 16.4 12.9 11.4 24.6
Typical week commencing March/April 13.7 10.7 9.5 20.5
Academic performance
All of the academic performance test scores The progress in academic performance in
like reading, writing and math, showed a reading -, writing – and math grades between
steady progress between the tests. However, the control room C1 and experimental room
there appears to have been a slightly higher E1 are shown in graphs below.
rate of improvement in the experimental
classes. Typical of these results are the
reading tests of which are shown in below.
6Tommy Govén, The influence of ambient lighting on pupils in classrooms
Graphs on academic performance
Mood Cortisol
The analysis of the monthly trend of the overall The analysis of the monthly trend of the cortisol
mood at 09:50 revealed a significant difference levels at 09:50 revealed a significant interaction
between the classes on the ground floor and between different months and the two floors.
those on the 1st floor.
On the ground floor the analysis of the monthly On the ground floor the analysis revealed a
trend of the overall mood at 09:50 revealed a tendency that the pupils in the experimental
significant difference between control room (C1) room (E1) showed higher levels of cortisol over
and the experimental room (E1) on the ground the whole school year than in the control room.
floor.
7Tommy Govén, The influence of ambient lighting on pupils in classrooms
On the first floor the analysis of the monthly On the first floor there was a significant
trend of the overall mood at 09:50 revealed a interaction between classrooms revealing that
minor difference between the control room and children in the experimental room (E2) showed
the experimental room. higher levels of cortisol, especially during the
darkest period than in the control room (C2).
10. DISCUSSION
It should be stressed that the findings 1) Fagerhult, Lighting Technology Dept,
presented in this paper are interim in nature Stockholm, Sweden,
and further results of analyses of the data will tommy.goven@fagerhult.se
be published as they become available.
2) Lund University, Faculty of Engineering,
However there are certain key trends that
Lund, Sweden,
have already been spotted in the data.
thorbjorn.laike@arkitektur.lth.se
There seem to be a general trend that
3) University College London, The Bartlett
there are differences between the
School of Graduate Studies, London, UK,
experimental rooms and the control rooms.
p.raynham@ucl.ac.uk
Improved ambient lighting may have an impact
on both the progress in academic performance 4) University College London, The Bartlett
and on the children’s mood. The improved School of Graduate Studies, London, UK,
ambient lighting showed a positive impact on k.sansal@ucl.ac.uk
the children’s mood at 09:50 in the morning.
The cortisol levels are also higher in the rooms
with improved ambient lighting, both on the
ground floor and on the first floor.
Furthermore, in three of the four rooms we
also found an increase of cortisol in February, Author
which also have been shown in earlier studies. Tommy Govén
All together we have now found several AB Fagerhult
indicators pointing in the same direction, Lighting Technology Manager
namely the improved ambient light affect Tegelviksgatan 32 SE-116 41 Stockholm,
individuals cognitive, emotional and biological. Sweden
Phone +46 36 10 85 00
The study also shows that the use of Direct +46 8 522 359 52
lighting controls has a major impact on use of Mobile +46 70 594 04 07
energy without harming the quality of light in Fax +46 8 714 97 60
classrooms. Further analyses of visual aspects tommy.goven@fagerhult.se
will be published. www.fagerhult.se
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