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Room temperature effects on office work

In “Creating the productive workplace”, Second Edition, Editor D. Clements-Croome,
London: Taylor and Francis, 2005 (In the press)
ROOM TEMPERATURE EFFECTS ON OFFICE WORK
David P. Wyon, Pawel Wargocki
International Centre for Indoor Environment and Energy
Technical University of Denmark
SUMMARY
Room temperature affects the productivity of office workers through the operation of
several mechanisms. Thermal discomfort distracts attention and generates complaints
that increase maintenance costs. Warmth lowers arousal, exacerbates SBS symptoms
and has a negative effect on mental work. Cold conditions lower finger temperatures
and so have a negative effect on manual dexterity. Rapid temperature swings have the
same effects on office work as slightly raised room temperatures, while slow
temperature swings just cause discomfort. Vertical thermal gradients reduce perceived
air quality or lead to a reduction in room temperature that then causes complaints of
cold at floor level. Individual control of the thermal microclimate reduces most of
these problems. Lighting level and noise can interact with room temperature in terms
of their combined effects on the performance of office tasks.
Keywords: Temperature, discomfort, SBS, individual control, offices, performance
INTRODUCTION
Thermal discomfort distracts people from their work, and it causes complaints, which
generate unscheduled maintenance costs. Many HVAC engineers take the cynical
view that there will always be complaints, whatever they do. Recent analysis of
complaints logs shows that this is not so: Federspiel (1998) demonstrated that if office
temperatures had always been in the 70-75 F range (21-24 C), 70% of "hot and cold
call-outs" would not have occurred, which would have reduced maintenance costs by
an estimated 20%. This cost reduction represents an increase in productivity in itself,
which is in addition to the undoubted productivity benefit of reducing thermal
discomfort. People who feel uncomfortable lose their motivation to work and tend to
take more breaks. Both of these effects reduce productivity. Many of the symptoms
characteristic of Sick Building Syndrome (SBS) become more intense and affect a
larger proportion of building occupants as air temperatures rise in the 21-24 deg C
range (Krogstad et al. 1993). People who do not feel very well do not work very well,
as documented by Nunes et al. (1993), so SBS is one way by which productivity can
be reduced. Cold conditions indoors cause vasoconstriction and this reduces skin
temperatures. Fingertip sensitivity and the speed of finger movements are below
maximum even at thermal neutrality, and other aspects of manual dexterity that can be
important for productivity are progressively reduced at temperatures below neutrality
- first hand-eye co-ordination, then muscular strength, as skin temperatures decrease
in response either to lower temperatures or to prolonged exposure (Meese et al. 1982).
Most office workers use computers during a substantial part of their working day.
Using a computer is a very special kind of work. It involves close attention to detail
and to small visual symbols, and therefore has a high optimal level of arousal. Modern
computers introduce little delay. They are almost always ready for the next input from
the user. This in itself is a stress factor for some people. Close attention to the screen
causes a reduction in blinkrate. The eyes of computer users are therefore dryer than
they would be if they were doing other kinds of work in the same environment. They
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are therefore more sensitive to airborne particulates, air pollution, low humidity, air
movement, thermal gradients and raised air temperatures. Unless they and their
computer are efficiently grounded, there is usually a static electrical charge between
them. This can concentrate airborne pollutants in the facial area and further increase
their eye discomfort and thermal sensitivity. Computers impose a particular posture.
Computer users are therefore less free to alter their posture than they would be if they
were doing other kinds of work in the same environment. This affects their heat
balance in two ways. Firstly, it reduces their ability to alter their rate of metabolic heat
production adaptively, so their thermal sensitivity is increased. Secondly, it reduces
their ability to adaptively alter the effective surface area of their body that is available
for losing heat to the immediate environment. Using a computer efficiently involves
rule-based logical thinking, if only to follow the rules of engagement imposed by the
programmer. Computer users have a high optimal level of arousal for this reason as
well. They exert effort to maintain it under unfavourable environmental conditions
and become more rapidly fatigued. These effects ensure that their productivity is
particularly sensitive to the thermal environment.
ROOM TEMPERATURE AND SBS
A survey by Preller et al. (1990) of large numbers of people working in Dutch office
buildings showed that individual control of temperature had a significant and positive
effect: sick leave due to SBS was as much as 30% lower in situations where
individual workers could control their own thermal environment, in comparison with
situations where they were obliged to accept conditions that were optimum for the
group rather than for the individual. Similar studies in UK offices by Raw et al.
(1990) indicate that self-estimates of efficiency are significantly higher when
individuals can control their own thermal climate, or their own ventilation, or the
lighting levels where they work, in comparison with similar offices where this is not
possible. This study also showed that while 2 SBS symptoms were quite normal, 6
SBS symptoms were associated with a 10% decrease in self-estimated efficiency. In
an experimental study by Nunes et al. (1993) in Canadian offices, workers reporting
any symptoms of SBS were found to be working 7.2% more slowly on one
standardised computer task, designated the Continuous Performance Task or CPT
(P<0.001), and to be making 30% more errors on another task designated the Symbol-
digit Substitution Task or SST. The CPT was a vigilance task in which subjects
monitored a series of displays appearing on a computer screen and had to respond to
one that had been designated as the target, while the SST was a complex coding task.
47 subjects performed each task once a week for three weeks, without supervision, as
part of their daily routine. These three papers provide strong and quantitative evidence
for the link between SBS and productivity. Any factor that reduces SBS will increase
productivity.
Fang et al. (2002) found no significant effect of temperature and humidity on
performance in 4.5-hour exposures ranging from 20°C/40%RH to 26°C/60%RH,
presumably because their subjects used clothing adjustments as intended to remain in
a state of thermal comfort, but fatigue, headache and difficulty in thinking clearly still
increased at 26°C and 60% RH, indicating that productivity might well be reduced in
a real workplace towards the end of a long day’s work.
An intervention experiment by Krogstad et al. (1991) of SBS symptoms experienced
by 100 workers in a computerised office at various imposed temperatures in the 19-24
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deg C range shows a very marked effect of thermal conditions on SBS. Each thermal
condition was maintained for a week. It is quite clear from these results that virtually
all SBS symptoms increase with temperature from a minimum at 20-21 deg C, and in
this study the effect was widespread rather than confined to a few sensitive
individuals: the proportion reporting headache and fatigue increased from 10% at 20-
21 deg C to over 60% at 24.5 deg C, and other SBS symptoms, including skin
problems, showed similar effects.
THERMAL GRADIENTS
The mechanisms by which SBS is reduced by small reductions in air temperature
seem likely to take place at head height, although there may also be a secondary effect
on such general symptoms as headache and fatigue that is linked to whole body heat
balance. Vertical thermal gradients are always positive, since hot air rises. In rooms
where the airflow must remove a high heat load, and particularly if this is to be done
by displacement rather than by complete or partial mixing, air temperature at head
height may be 2-3 deg K higher than at floor height. Cold feet and warm air to breathe
is the exact opposite of human requirements, and an individual who experiences SBS
or sensations of dryness will often be forced to lower the room temperature to such an
extent that it will be too cold for whole body heat balance as well as too cold for the
feet. Over 40% were found to experience local thermal discomfort even when
displacement ventilation had been adjusted to provide preferred whole-body heat loss
when 72 subjects were exposed for one hour to two typical winter and two typical
summer conditions in an office module by Wyon & Sandberg (1990). The experiment
on which the recommendations in ISO 7730 are based (Olesen et al. 1979) would
have predicted only 5% dissatisfied under these conditions. The discrepancy is due to
the fact that each subject in the original Danish experiment was allowed to adjust the
temperature continuously in the second half of the experiment and could therefore
compensate for the discomfort of the imposed thermal gradient.
In a later experiment by Wyon & Sandberg (1996), in which over 200 subjects were
exposed for one hour to vertical temperature differences of 0, 2 and 4 deg K per
meter, with room temperatures resulting in the same three states of whole body heat
balance at each vertical temperature difference, local thermal discomfort was found to
be unaffected by vertical temperature difference, but highly sensitive to whole body
heat balance. Similar results have recently been reported by Ilmarinen et al. (1992)
and Palonen et al. (1992), using only 6 subjects. These experiments do not deal with
the consequences of vertical temperature differences for sensations of dryness or SBS
over longer periods, but they do indicate that thermal gradients are only a problem
because they lead to an increase in air temperature in the breathing zone. Even if the
individual has a choice in the matter, it is an uncomfortable one, between the risk of
SBS and a room temperature that is too low for comfort. Whichever is chosen, the end
result is likely to be that productivity is reduced by vertical temperature differences.
THERMAL COMFORT AND PERFORMANCE
Thermal conditions providing optimum comfort may not give rise to maximum
efficiency. In an experiment by Pepler & Warner (1968) in which normally clothed
young American subjects performed mental work at different temperatures, they were
most thermally comfortable at 27 deg C, the temperature at which they exerted least
effort and performed least work. They performed most work at 20 deg C, although
most of them felt uncomfortably cold at this temperature.
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PERFORMANCE IN COLD CONDITIONS
In a study by Meese et al. (1982), 600 South African factory workers were randomly
assigned to work for 6.5 hours at 24, 18, 12 or 6 deg C in the same clothing ensemble.
Performance of a wide variety of simulated industrial tasks involving finger strength
and speed, manual dexterity, hand steadiness and a variety of well-practiced
manipulative skills was found to decline monotonically with room temperature below
thermal neutrality. The critical room temperature for unimpaired performance was
either 18 or 12 deg C, depending on the task. Finger speed and fingertip sensitivity
were measurably impaired at the air temperature preferred for thermal comfort (18
deg C), in comparison with the air temperature (24 deg C) at which finger
temperatures were at their maximum value. Finger strength was maintained at 18 and
12 deg C but was measurably reduced at 6 deg C. A realistic laboratory simulation of
one of the heaviest tasks still performed manually in industry was also part of the
series: the proportion of poor welds made with a heavy but counterbalanced spot-
welding apparatus was three times greater at 6 deg C than it was at 18 deg C.
PERFORMANCE IN HOT CONDITIONS
The critical temperature for performance in temperate zones seems to lie at about 30
deg C for normal humidity levels. This conclusion was reached by Pepler (1964) on
the basis of studies made in weaving sheds and coalmines by the Industrial Fatigue
Research Board in England.
Performance of simulated industrial work is worse at 10 deg C than at 17 deg C, and
worse at 24 deg C than at 20 deg C. These conclusions were drawn respectively by
Pepler (1964), from the Industrial Fatigue Research Board experiments, and by Wyon
(1974), from the report of the New York State Commission on Ventilation. Both
experiments were carried out under realistic working conditions, subjects working a
full 8-hour day for several weeks. Field experiments in South Africa (Wyon et al.
1982; Meese et al. 1982; Kok et al. 1983) indicate corresponding effects on the many
industrial tasks that were studied both above and below thermal neutrality, although
the temperature for optimum performance was found to lie as much as 10 deg K
higher for these heat-acclimatised factory workers.
OFFICE WORK IN WARM CONDITIONS
Provins (1966) was one of the first to formulate the principle that moderate heat stress
lowers arousal, while higher levels of heat stress, e.g. above the sweating threshold,
raise arousal. There is no corresponding evidence that arousal is raised by moderately
cool conditions, below thermal neutrality. Easterbrook (1959) had already
summarised a great deal of evidence for the effects of arousal on mental performance,
showing that raised arousal leads to reduced cue-utilisation, or breadth of attention,
whatever the external or internal driving factor may be. Bursill (1958) had already
demonstrated that high levels of heat stress reduced breadth of attention, and Hockey
(1970) later showed that loud background noise could indeed produce the same effect.
It is to be expected that bright lighting would produce a similar effect.
Thermal conditions below neutrality are unlikely to have any directly negative effects
on mental performance, but there will be a generally distracting and de-motivating
effect via the mechanism of cold discomfort. Langkilde et al. (1973) found no
negative effects on mental performance of room temperatures 4 deg K below
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individual neutrality. It might be thought that having cool air to breathe would in itself
raise arousal and enhance the performance of tasks with a high optimal level of
arousal, but it seems that the thermal state of the body, however achieved, is what
determines arousal and thus performance: no difference in the performance of a whole
battery of different tasks was found between two conditions of thermal neutrality with
very different clothing insulation and air temperature: 0.6 Clo at 23 deg C and 1.15
Clo at 19 deg C (Wyon et al. 1975). In other words, thin clothing and warm air is
equivalent to warm clothing and cool air, in terms of performance as well as thermal
comfort.
Under moderately warm conditions, above neutrality, it is possible to avoid sweating
by reducing metabolic heat production. This leads to a lowering of arousal, as subjects
relax and generally try less hard to work fast. This is often a completely unconscious
response to warmth. Schoolchildren at 27 deg C (Holmberg & Wyon 1969, Wyon
1969), students at 27 deg C (Pepler & Warner 1968, Wyon et al. 1979), office workers
at 24 deg C (Wyon 1974), all showed decreased concentration and 30-50% lower
performance of tasks requiring concentration at temperatures just below the sweating
threshold for sedentary work. Aspects of mental performance with a low optimal level
of arousal, such as memory (Wyon et al. 1979) and creative thinking (Wyon 1996a)
are improved by exposure to a few degrees above thermal neutrality, but they too are
impaired at higher temperatures, closer to and above the sweating threshold. Similar
effects are to be expected for unprepared vigilance, which requires the greatest
possible breadth of attention. This should not be confused with what is often termed
vigilance, the ability to respond rapidly when an expected signal is detected, which is
a very simple task with a high optimum level of arousal. Under conditions in which
relaxation and reduced arousal would be dangerous, for example when in control of a
moving vehicle, even moderate heat stress tends to raise arousal and therefore to
reduce unprepared vigilance (Wyon et al. 1996).
Mental performance has been studied as a function of dynamic temperature swings
with periods up to 60 minutes by Wyon et al. (1971, 1973, 1979). These three
experiments were summarised by Wyon (1979). Subjective tolerance of temperature
swings was greater while working than while resting. The performance of routine
work requiring concentration was reduced by small and relatively rapid temperature
swings (peak-to-peak amplitudes up to 4 deg K and periods up to 16 minutes).
Physiological response to cold appeared to take place faster than response to warmth
under these conditions, so their net effect was equivalent to a slight increase in room
temperature in terms of its effect on the rate of loss of heat from the body. Large
temperature swings (peak-to-peak amplitudes up to 8 deg K and periods up to 32
minutes) had a stimulating effect that actually increased rates of working, but thermal
discomfort was experienced at the peaks and troughs. For periods of 60 minutes or
more, physiological thermoregulation is sufficiently fast to keep pace, and
performance is a function of the temperature at any given time. It would seem that
there is no advantage in imposing temperature swings in indoor environments
designed for mental work. Individual control of the thermal environment for optimal
performance is another matter entirely.
The arousal model of environmental effects on performance predicts that noise and
bright lighting will interact with thermal stress by increasing arousal. A background of
recorded playground noise at 85 dBA removed the beneficial effect of warmth on the
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performance of a test of creative thinking by 12-year-old boys (Wyon 1969).
Intermittent noise (equivalent to 85 dBA) reduced the negative effects of warmth (27
deg C), while noise removed the beneficial effects of warmth, in the performance of
two complex tasks by adult factory workers (Wyon et al. 1978). An analogous
interaction between lighting intensity and moderate thermal stress was observed by
Löfberg et al. (1975) in a climate chamber experiment in which 144 ten-year-old
children were exposed to warmth or thermal neutrality at 60, 250 and 1000 lux.
Extreme heat stress raises arousal and therefore acts in the same direction as noise and
bright lighting. Dim lighting and low levels of monotonous background noise can be
assumed to reduce arousal and would be expected to increase the effects of moderate
heat stress.
INDIVIDUAL CONTROL
People differ in their clothing and metabolism, and in the requirements of the work
they do at any given time. This means that there will always be differences of opinion
as to whether it is too hot or too cold. The ASHRAE Handbook of Fundamentals
(1997) suggests that an acceptable percentage comfortable would be 80%, but does
not attempt to predict the degree of individual control that would be necessary to
ensure that a higher percentage could achieve thermal comfort. Using the value 1.17
deg K for the SD of individual neutral temperature which was found in an experiment
by Wyon & Sandberg (1996) in which 200 subjects wore their habitual office clothing
and assuming the usual Normal distribution of response, it may be calculated that
99% of office workers would be thermally comfortable if the equivalent room
temperature provided by their microclimate could be individually adjusted over a
range of 6.0 deg K, 95% with 4.6 deg K, and 90% with 3.9 deg K. Dress codes
increase these ranges.
Wyon (1996b) demonstrated that individual control equivalent to ±3 deg K would be
expected to improve the performance of mental tasks requiring concentration by
2.7%. A decrease of this magnitude (2.8%) in the rate of claims-processing in an
insurance office had been demonstrated by Kroner et al. (1992) when individual
microclimate control devices in an insurance office were temporarily disabled. It was
also shown that this degree of individual control might be expected to improve group
mean performance of routine office tasks by 7%, and performance of manual tasks for
which rapid finger movements and a sensitive touch are critical by 3 & 8%
respectively. Although thermal conditions above the group mean for thermal
neutrality will still reduce the group mean performance of mental work, the expected
benefits of individual control for group performance are actually larger under warm
conditions up to 5 deg K above the group optimum than they are at the optimum. The
insurance clerks in Kroner's intervention experiment worked in cubicles in an open
office. The individual control of which the intervention deprived them was provided
by desk-mounted devices connected to supply-air ducts. Non-ducted devices requiring
only a power connection are more easily moved and can still control local radiant
temperature and air velocity. Ceiling, wall and floor-mounted devices are obviously
easier to connect to ducts, but are more difficult to adapt to new furniture and partition
configurations.
It is obviously easier to provide complete individual control if there are four full-
height walls and a closed door around each person. This is an expensive solution, both
in terms of the first cost and of the floor area required for offices and their access by
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corridor. Open offices that are also used as corridors can accommodate more people
in the same floor area at a lower first cost. Communication on a minute-by-minute
basis is better between team members who occupy the same room than if they were all
in separate offices, and this is advanced as an argument in favour of open offices.
Cubicles provide visual screening, but very little acoustic screening. Everybody who
has ever tried to work in a large library knows what a high level of discipline and
consideration is required for this to be possible. These courtesies are rarely
encountered in open offices. Telephones ring, conversations are held, and visitors
arrive and leave all the time. Any interruption affects everybody to some extent.
Witterseh et al. (2002) demonstrated that open office noise distraction can have both
negative and positive effects, and that room temperature effects interact with noise
distraction effects. Subjects clothed for comfort at 22°C were exposed for 3h to 22°,
26° or 30°C in quiet (35dBA) or recorded open-plan office noise (55dBA) conditions.
The noise distraction was very realistic, replayed from a high-quality Digital Audio
Tape-recorder (DAT) through loudspeakers hidden behind the partition (instead of a
source of air pollution) and during 50% of the time it included clearly audible
conversation in a language understood by the subjects. Warmth decreased Perceived
Air Quality and increased odour intensity and stuffiness. It increased eye, nose and
throat irritation and headache intensity and decreased concentration and self-estimated
performance. Noise increased fatigue and decreased concentration but did not interact
with any thermal effects on subjective perception. In the Addition task, noise
decreased the work-rate by 3%, subjects who felt too warm made 56% more errors
and there was a noise-temperature interaction: the effect of warmth on errors was less
in noise. Noise increased the speed of typing and proofreading. In the noise distraction
condition, the creative thinking task was performed worse at 30°C than at lower
temperatures. Temperature and noise distraction thus affect both symptoms and
performance, but interact only in their effects on performance.
VALIDATING EFFECTS ON PRODUCTIVITY
A small cross-sectional study in a telecommunication call-centre indicated that in the
area where temperatures remained below 25 C, operator performance was better:
average talk-time was 5-7% lower than it was on the sunny side of the call-centre
(Niemelä et al., 2002). Temperatures above 25.4 C caused qualified nurses providing
medical advice in a call-centre to work 16% more slowly when writing up their
reports after the call was over (i.e. wrap-up time increased) (Federspiel et al., 2002). A
third field experiment was performed in an office building in the Tropics by Tham et
al. (2003) to validate thermal effects on office work. Call-centre operator
performance, as indicated by average talk-time, improved by 4.9% when the air
temperature was decreased by 2°C from 24.5°C at the normal outdoor air supply rate
of 10 L/s/p. It improved by 8.8% when the outdoor air supply rate was raised to 23
L/s/p at the original indoor air temperature of 24.5°C. A subsequent analysis in terms
of total call-handling time, as yet unpublished, confirms the reversibility of these
effects. Thermal discomfort increased at the lower temperature but no other subjective
symptoms were affected. The productivity of call-centre operators in the Tropics
could thus be improved by maintaining conditions on the cool side of thermal
neutrality. This study was modelled on the field validation experiment described in
the chapter on IAQ effects on office work.
ACKNOWLEDGMENTS
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This chapter is based on a literature review by Wyon (1993), now abridged and
updated.
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... A recent analysis done by [4] based on approximately 90,000 occupant satisfaction survey responses found that roughly 40 % of occupants are dissatisfied with their thermal environment. Thermal comfort affects health [5,6], office work performance [7,8,9,2], learning performance [10,11,12], and well-being [13,14]. ...
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We introduce Cohort Comfort Models, a new framework for predicting how new occupants would perceive their thermal environment. Cohort Comfort Models leverage historical data collected from a sample population, who have some underlying preference similarity, to predict thermal preference responses of new occupants. Our framework is capable of exploiting available background information such as physical characteristics and one-time on-boarding surveys (satisfaction with life scale, highly sensitive person scale, the Big Five personality traits) from the new occupant as well as physiological and environmental sensor measurements paired with thermal preference responses. We implemented our framework in two publicly available datasets containing longitudinal data from 55 people, comprising more than 6,000 individual thermal comfort surveys. We observed that, a Cohort Comfort Model that uses background information provided very little change in thermal preference prediction performance but uses none historical data. On the other hand, for half and one third of each dataset occupant population, using Cohort Comfort Models, with less historical data from target occupants, Cohort Comfort Models increased their thermal preference prediction by 8~\% and 5~\% on average, and up to 36~\% and 46~\% for some occupants, when compared to general-purpose models trained on the whole population of occupants. The framework is presented in a data and site agnostic manner, with its different components easily tailored to the data availability of the occupants and the buildings. Cohort Comfort Models can be an important step towards personalization without the need of developing a personalized model for each new occupant.
... The occupant perceives, and through that action interprets, the work process in a space-time relationship [31]. When thermal conditions are inadequate, a worker becomes distracted [32] and consequently his or her immediate purpose is changed. This alters in their relationship with the environment through actions that can generate a thermal change, thus affecting the worker and others around them. ...
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The evaluation of productivity in office buildings is particularly complex; studies indicate that occupants’ perceptions reflect thermal conditions and are therefore an important element to consider. This research reveals the interrelationships and relative influences of the thermal environmental factors of offices on the perceived productivity of workers. Through fieldwork conducted in winter and summer in 18 Chilean office buildings, information was collected from 940 occupants on 32 variables related to the thermal environment and self-perceived productivity. A total of 3551 responses were used together with environmental and physical data on the indoor built space to formulate a model that recognizes the effect of the thermal environment on productivity. In this model, the constructs of individual thermal sensation, thermal preference, and thermal acceptability are mediating variables that originate in different office parameters and influence perceived productivity. Subsequently, the model was validated and specified following the SEM methodology, thereby resulting in a reduced model of 10 significant variables. An analysis of the interrelationships established the importance of these variables associated with the design of built space and the management of comfort strategies considering work productivity.
... Reference [13] found that office workers who were uncomfortable with typical thermal conditions in their workspace showed a higher prevalence of headache, throat, and eye irritation. In addition, Ref. [30] suggested that rapid temperature swings aggravate sick building syndrome symptoms and have detrimental effects on cognitive performance. Furthermore, extreme thermal events can result in conditions such as hypothermia or heat stroke and can increase cardiovascular mortality, especially among children and the elderly [31]. ...
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The outbreak of SARS-CoV-2 virus forced office workers to conduct their daily work activities from home over an extended period. Given this unique situation, an opportunity emerged to study the satisfaction of office workers with indoor environmental quality (IEQ) factors of their houses where work activities took place and associate these factors with mental and physical health. We designed and administered a questionnaire that was open for 45 days during the COVID-19 pandemic and received valid data from 988 respondents. The results show that low satisfaction with natural lighting, glare and humidity predicted eye related symptoms, while low satisfaction with noise was a strong predictor of fatigue or tiredness, headaches or migraines, anxiety, and depression or sadness. Nose and throat related symptoms and skin related symptoms were only uniquely predicted by low satisfaction with humidity. Low satisfaction with glare uniquely predicted an increase in musculoskeletal discomfort. Symptoms related to mental stress, rumination or worry were predicted by low satisfaction with air quality and noise. Finally, low satisfaction with noise and indoor temperature predicted the prevalence of symptoms related to trouble concentrating, maintaining attention or focus. Workers with higher income were more satisfied with humidity, air quality and indoor temperature and had better overall mental health. Older individuals had increased satisfaction with natural lighting, humidity, air quality, noise, and indoor temperature. Findings from this study can inform future design practices that focus on hybrid home-work environments by highlighting the impact of IEQ factors on occupant well-being.
... For example, polluted indoor air can be considered an environmental demand, as it has a neg ative impact on cognitive performance ( Allen et al., 2015 ;Satish et al., 2012, Zhang, Wargocki, Lian, & Thyregod, 2016 and contributes to the development of 'sick building syndrome' symp toms, such as headaches, tiredness, and respiratory difficulties ( Seppänen, Fisk, & Mendell, 1999 ;Tsai, Lin, & Chan, 2012 ). Other environmental factors which could deplete employees' ener getic reserves might include uncomfortable temperatures ( Rupp, Vásque, & Lamberts, 2015 ;Wyon & Wargocki, 2006 ), inadequate lighting (Boyce et al., 2006), and insufficient exposure to daylight ( Jamrozik et al., 2019 ) (see also Chapter 13 The Theory of Attractive Quality). ...
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For decades, the Job Demands-Resources (JD-R) Model has been used in a plethora of studies about the psychosocial and physical conditions associated with job stress or strain, resulting in disability, disease, and/or poor job performance. Simply, job strain occurs in a situation of overwhelming demand in the face of resource scarcity. Many of these demands and resources can arise directly from the workplace environment itself. To provide a simple framework for workplace practitioners to understand the complex relationship between the employee and the workplace, this chapter presents a domain-specific extension of the JD-R Model, termed the Environmental Demands-Resources (ED-R) Model. Then, we draw upon psychological theories of universal human needs to explain the workplace resources deemed foundational for human flourishing and fortification in the face of overwhelming challenge. This perspective aligns with the goals of the modern organization for a sustainable and regenerative workplace by intentionally creating benefits instead of merely avoiding harms. © 2021 selection and editorial matter, Michael Roskams, Eileen McNeely, Dorota Weziak-Bialowolska, and Piotr Bialowolski.
... The recommended values of current thermal environment design parameters in the design code, such as indoor temperature, are difficult to use to directly guide classroom environmental design. Relevant researches [29,30] have shown that reducing the indoor temperature can appropriately help improve learning performance based on the existing thermal comfort temperature. In ...
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Indicators and methods in current thermal comfort evaluation models are based on the average level for entirely society, which is difficult to use to a direct guide for the design of classroom thermal environments in primary and secondary schools. The determination of indoor parameters is mainly based on a single thermal comfort index, with little consideration of the impact of thermal environment on learning performance, and combinations of both considerations is even rarer. The quantitative relationship between temperature and thermal comfort was established, with percentage of satisfied as a thermal comfort evaluation index. The quantitative relationships among percentage of qualified, performance index, and temperature were established with the group's percentage of qualified was proposed to characterize learning performance. Therefore, a method for determining the temperature design parameters of the classroom was proposed, taking into consideration the comprehensive effects of thermal comfort and learning performance. Temperature ranges of different thermal comfort and learning performance levels were recommended. The upper limit of the recommended temperature with higher comfort and learning performance was 5 °C lower than the low limits of international standards, which could effectively reduce energy consumption of school buildings in winter, and provide a theoretical basis for improvement of classroom environment design.
... Nevertheless, when the thermal conditions are inadequate, the worker becomes distracted by their discomfort. It is then that his or her immediate focus and objectives change (Wyon & Wargocki, 2006). That is to say, cognitive reserve can be thought of as part of work normality. ...
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This study examines the perceived productivity of office occupants in moderate thermal environments in Chile. Specifically, it analyses environmental parameters and contrasts participants’ self-reported answers to cross-sectional and retrospective questionnaires. To this end, data were collected for one day in winter and one day in summer, in eighteen office buildings in the cities of Concepción and Santiago. The results show that the average operative temperatures are 22.2 °C in winter and 23.5 °C in summer. 80.5% of the occupants declared their productivity to be normal on the cross-sectional survey. However, on the retrospective survey, 82.7% said that their productivity is affected by the thermal environment. To reveal the interrelationships between perceived productivity and the thermal environment, a categorical principal components analysis was carried out. It demonstrated that there is only a relationship between cross-sectional and retrospective productivity in winter. Subsequently, a good-fitting structural equation model was created, which showed that different relationships exist between the variables. These findings could enable organizations and design professionals to better understand occupants’ perceived productivity in relation to thermal conditions in office buildings.
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The effect of thermal discomfort on human well-being and performance was studied in the field office, and an attempt was made to elucidate its psychological mechanism. Thirty participants were recruited to perform subjective evaluations and performance tests under 5 different conditions (25 °C, 27 °C, 29 °C, 31 °C, 33 °C). During the experiment, the air temperature was considered as an independent variable and other parameters were kept at the same level. The results show that thermal discomfort can lead to poor comfort and reduced performance, and people report that many sick building syndrome symptoms are intensified, showing more negative emotions and reducing their motivation. When people's thermal sensation vote is -0.13, the best performance can be obtained. But the changes in human performance are not only caused by objective environmental factors, but also by psychological factors such as emotion and motivation. When people's negative emotions decrease or their motivations increase, performance will also increase.
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High stress levels and sleep deprivation may cause several mental or physical health issues such as depression, impaired memory, decreased motivation, obesity, etc. The COVID-19 pandemic has produced unprecedented changes in our lives, generating significant stress, and worries about health, social isolation, employment and finances. To this end, nowadays more than ever, it is crucial to deliver solutions that can help people to manage and control their stress, as well as to reduce sleep disturbances, so as to improve their health and overall quality of life. Technology, and in particular Ambient Intelligence Environments, can help towards that direction, consider-ing that they are able to understand the needs of their users, identify their behavior, learn their preferences, and act and react in their interest. This work presents two systems that have been de-signed and developed in the context of an Intelligent Home, namely CaLmi and HypnOS, which aim to assist users that struggle with stress and poor sleep quality respectively. Both systems rely on real-time data collected by wearable devices, as well as contextual information retrieved from the ambient facilities of the Intelligent Home, so as to offer appropriate pervasive relaxation pro-grams (CaLmi), or provide personalized insights regarding sleep hygiene (HypnOS) to the residents. This article will describe the design process that was followed, the functionality of both systems, the results of the user studies that were conducted for the evaluation of their end-user applications, and a discussion about future plans.