Indoor climate, health and performance

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Transcript Indoor climate, health and performance

Dagslys, indeklima og energibalance
Betydningen av dagslys i bygninger – hvad er et godt indeklima og hvad
er energibalance?
Jens Christoffersen, VELUX A/S
Why Daylight ...?
We prefer daylight
Daylight is free and
Daylight is available from
sunrise to sunset; and
working hours
Significant energy saving
Quality: View, light, and
Why daylight?
© Lars B. Hansen, Philips Lys, LTS - møde Hvad er god lysstyring?
© Thomas Drejer, LouisPoulsen, LTS - møde Hvad er god lysstyring?
Next level of daylighting design
Daylight, Health & well-being - all aspects
Visual aspects of light
M. Knoop - Dynamic lighting for well-being in work places.
Philips Lighting, LiDAC & TU/e, October 2006
Adequate Daylight
- Daylight factor = 2%…?
The daylight factor (DF) express
the daylight availability in a room.
It describes the ratio of inside
illuminance over outside
illuminance, expressed in per cent.
The higher the DF the more natural
light is available in the room.
The DF is often expressed for a
fixed point within the e.g at the
desk or at the centre of the room
Adequate Daylight
- Daylight factor = 2%…?
North-facing in St. Petersburg
or South-facing in Miami?
For a given design you get the
same daylight factor either way,
independent of orientation,
climate, latitude etc.
BUT interior light levels is
Overcast, winter (DK):
Eud ≈ 5.000 lux → Eind ≈ 100 lux
Overcast, summer (DK):
Eud ≈ 30.000 lux → Eind ≈ 600 lux
Adequate Daylight
- Daylight factor = 2%…?
Adequate Daylight
- Daylight factor = 2%…?
Krav til dagslys kan verifiseres
enten ved beregning som bekrefter
at gjennomsnittlig dagslysfaktor i
rommet er minimum 2 %
.... eller ved at rommets
dagslysflate utgjør minimum 10 %
av bruksarealet.
Ved bruk av gjennomsnittsverdi for
dagslysfaktor oppnås et godt
utgangspunkt for tilfredsstillende
tilgang på dagslys i alle typer rom,
uavhengig av størrelse.
Adequate Daylight
- Daylight factor = 2%…?
Adequate Daylight
- Daylight factor = 2%…?
23 forskellige modeller med sidelys
eller ovenlys
Dagslysflaten er 10 eller 15% af
gulvareal (≈ bruksflaten ?)
Kun 9 ud af 23 modeller har en
gennemsnittelig DF ≥ 2%
Kun 1 ud af 23 modeller med sidelys
har en dagslysflate på 10% og en
gennemsnitlig DF ≥ 2%
2 modeller med ovenlys og dagslysflate på 7% gav en gennemsnitlig DF
≥ 2%
Adequate Daylight
- Daylight factor = 2%…?
British Standard
DIN 5034-1
Daylight and Windows
Is it possible to address a more 'holistic'
approach to daylight requirements?
The building design need to include a number of
parameters, such as:
daylight and sunlight penetration
window views and content of view
enclosed or open space
visual and acoustical privacy
personal control of ambient conditions etc.
light levels appropriate for ‘task’
glare from windows
Daylight and Windows
Is it possible to address a more 'holistic'
approach to daylight requirements?
Daylight and Windows
Is it possible to address a more 'holistic'
approach to daylight requirements?
Useful Daylight Illuminance
A human-factors based daylight metric
Emotional aspects of light
The Role of Daylight
Research identified benefits of daylight and sunlight as well as view
for worker health and well-being
Less eyestrain (Cowling et al., 1990), higher productivity (Visher
1989), more effective learning (Heshong et al 1999)
Daylight is better for psychological comfort, for office appearance
and pleasantness, for general health and visual health, and for color
appearance of people and furnishings (Heerwagen et al., 1986)
Surveys consistently show that people prefer daylight over electric
light and that they believe it to be more healthful (Heerwagen &
Heerwagen, 1986; Veitch et. Al, 1993 / 1996).
Having a window, or having access to daylight, improves
satisfaction with lighting (Christoffersen et al., 1999; Butler & Biner,
1989; Cuttle, 1983; Heerwagen & Heerwagen, 1986, Veitch et al.,
2003), and satisfaction with the view from an office is greater for
natural scenes than man-made scenes (Christoffersen et al., 1999).
Non-visual aspects of light
Daylight and Health
People in industrialized countries
might not be receiving sufficient
daily light exposure to maintain
optimal health (CIE, 2004)
Necessary daily light dose is not
known and the describing optimal
pattern of light exposure is in its
early stages.
The implications for daylighting,
architecture, and lighting design are
Daylight and Health
Several studies have found that people who receive higher daily
light exposures show improved mood, improved quality of social
interactions, and greater feelings of vitality
aan het Rot et al., 2007; Espiritu et al., 1994; Kripke et al., 2005; Leppamaki et
al., 2004; Leppämäki et al., 2002
Electric lighting could meet the needs for daily light exposure
But the need to improve energy-efficiency and reduce greenhouse
gas emissions means that the most efficient way to increase daily
light exposure will likely involve increased use of daylighting in
new buildings and in retrofits of existing buildings.
.... and maybe accept ‘new working rules’ according to time-of-day
walks, e.g. Wirz-Justice et al. (1996) found that subjects with SAD
were treated more successfully by taking a one-hour walk each
morning (illuminance ~ 1000 lx) than by 30-minute exposure to
bright electric light (illuminance ~ 2800 lx)
Daylight and Health
Indication of the relationship of subjective sleep
quality as a function of vertical illuminance at the
daytime working place (Ariens, 2005).
Higher daytime illuminance – Better sleep quality
Indoor Environment and SAD
Around 10-15 % of the
population in Northern
Europe is suffering from
SAD or a milder form of
seasonal mood
It helps to:
Make your environment
sunnier and brighter
Get outside / Exercise
Ventilation and indoor air quality
Ventilation – why?
The human factors
Health: Remove chemicals, particles, smells, allergenes, moulds
Psychological: Create link to outside
Comfort: Achieve thermal comfort
Health: Avoid allergies, asthma,
cardiovascular and other illnesses
Less illnes with good air
Performance: Support productivity and
feeling of well-being
Higher productivity with
good air quality
Indoor Environment and Health
Allergic rhinitis
Prevalence (%)
1952- 1957- 1962- 1967- 1972- 19771956 1961 1966 1971 1976 1981
Data for Sweden (Bråbäck et al 2004)
We see an increase
in illnesses which is
considered to be
linked to the indoor
Indoor Environment and Health
Increased temperatures and
poor air quality can reduce
performance of office
workers by 5% to 10%
Temperature ( C)
Pawel Wargocki, Indoor Air 2011
Indoor Environment and Performance
If children are taught in
a good indoor climate
their ability to learn
increases by 15%
Pawel Wargocki, Indoor Air 2011
Students with the most
daylighting in their
classrooms progressed
20% faster on math
tests and 26% on reading
End Users ?
Transfer of knowledge
We need to bring our knowledge to the designer, as one of the
main targets
Essential that the information provided is clear, simple and
to minimize poor design resulting in short- and long-term effects of
the people within the building.
Not adopt research results into a building design that is completely
different from the context in which they where found.
And we need also some common language
Transfer of knowledge
◘ From Marie-Claude Dubois
Active House - Specification
Performance-based criteria
Criteria based on international
standards and well-known methods
Only the most essential criteria – to
minimise evaluation workload
Two types of criteria
Quantitative; score 1 – 4
Active House - Specification
Light & view out
Thermal Environment
Indoor Air Quality
Noise and Acoustics
Emissions to air, soil and water
Consumption of non-renewable energy resources
Freshwater consumption and waste water treatment
Direct sunlight availability
Thermal Environment (1)
Indoor Air Quality (1)
Indoor Air Quality (2)
Windows and Energy
From U-value to energy balance
Focus on U-value in legislation – but incorrect only to consider heat
loss and not gain to evaluate the window’s effect on the building
“Energy balance” includes both heat loss and solar gains – more fair
than just U-value and provides a better choice of product
Solar gain
Heat loss
Energy balance
Energy balance
Energy balance is expressed in kWh/m² of window
If positive: the window contributes with energy for heating during the
heating season
If negative: the window is a cause of heat loss during the heating
Solar gain
Heat loss
Energy balance
Energy balance - orientation
Same heat loss in all
More solar gains
towards S
 Best total
performance in S
From method in the Danish 2010 building regulations
- it’s all about finding the right balance
©Lars Hansen & Politiken, 2003
… and not leave us in “search of the good light“ …
.... but also enjoy the exterior light !
- with care!