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Daylighting in environmentally certified buildings. Subjective and objective assessment of MKB Greenhouse, Malmö, Sweden

Levin, Therese LU (2017) AEBM01 20171
Energy and Building Design
Abstract
What could be considered an adequate level of daylight in buildings has become a debated question in the Swedish building industry. The current daylight requirements are often found difficult to meet in practice, especially in combination with other requirements regarding energy use. Outdated daylight requirements in the national building code combined with limited knowledge about the subjective impression of daylight in residential buildings are two issues that form the bottleneck around the question of daylight and energy in buildings. Daylight is of great importance to our health and well-being. It is thus important to identify an adequate daylight level while defining an appropriate expression of this level through relevant daylight... (More)
What could be considered an adequate level of daylight in buildings has become a debated question in the Swedish building industry. The current daylight requirements are often found difficult to meet in practice, especially in combination with other requirements regarding energy use. Outdated daylight requirements in the national building code combined with limited knowledge about the subjective impression of daylight in residential buildings are two issues that form the bottleneck around the question of daylight and energy in buildings. Daylight is of great importance to our health and well-being. It is thus important to identify an adequate daylight level while defining an appropriate expression of this level through relevant daylight metrics in building codes and certification systems. This study focuses on the tenants’ subjective impression of the daylight conditions in the apartments of MKB Greenhouse, Malmö, Sweden. The goal of this study is to link the subjective impression of daylight to objectively measured and simulated data. This study contributes to knowledge in the field that will help to determine suitable daylight conditions in future energy efficient multi-family dwellings. Self-administered questionnaires are used to collect information about the subjective impression of daylight in Greenhouse. Physical measurements are carried out and existing daylight simulations are further analyzed and discussed in relation to both measurements and subjective assessments. The subjective assessments show that the respondents have a clear preference for daylighting and that their perception of daylight level is affected by other parameters than the daylight factor alone. The objective assessment shows that the daylight factor (DFp) varies between 0.8-1.2% in the main living spaces of the apartments. Linking the objective results to the subjective ones, the results of this study is that the objective daylight level does not correspond to the expected level of subjective satisfaction. The final conclusion is thus that a lower threshold than the current (DFp ≥ 1.2%) is not recommended. (Less)
Popular Abstract
Regular exposure to daylight is crucial from a health perspective. Most people spend as much as 90% of the time indoors and depend on adequate daylight levels indoors to secure a sufficient daily dose of light. What could be considered an adequate level of daylight in buildings has become a debated question in the Swedish building industry. Recently, the interest for daylighting has grown, which has drawn attention to the fact that the current requirement of meeting a 1% point daylight factor is difficult to meet in practice. The building industry has questioned the threshold for being set too high, while daylighting experts disagree. This study indicates that a threshold below the current level is not recommended in future daylight... (More)
Regular exposure to daylight is crucial from a health perspective. Most people spend as much as 90% of the time indoors and depend on adequate daylight levels indoors to secure a sufficient daily dose of light. What could be considered an adequate level of daylight in buildings has become a debated question in the Swedish building industry. Recently, the interest for daylighting has grown, which has drawn attention to the fact that the current requirement of meeting a 1% point daylight factor is difficult to meet in practice. The building industry has questioned the threshold for being set too high, while daylighting experts disagree. This study indicates that a threshold below the current level is not recommended in future daylight regulations.

There is need for modernization and clarification of the daylight requirements in the national building code. The ongoing debate concerns what could be considered both realistic in practice and appropriate considering health and well-being of the occupants. One problem in this intense debate is the poor knowledge of the subjective impression of daylight. In other words, it is important to understand how daylight is perceived before deciding what threshold to use in future regulations. Objective daylight conditions, i.e. what is measured or simulated using advanced simulation tools, need to be linked to the subjective impression of the conditions. This study focuses on this particular matter and can hopefully contribute to knowledge that may be useful for determining suitable daylight conditions in future daylight regulations. An energy-efficient multifamily building in Malmö, Sweden, was studied using self-administered questionnaires to building occupants, on-site measurements under overcast sky conditions and advanced light simulations. The building is designed to meet the daylight requirements of a Swedish environmental certification system,”Miljöbyggnad”, which are based on the daylight chapter in the national building code. This means that the objective daylight conditions in this building are comparable to what is required in the national building code. Due to limited time and budget of this study, the questionnaires were only distributed during the winter season, when daylighting is scarce in Sweden. The project is ongoing, with plans of further questionnaire investigations as well as a more detailed statistical analysis of the results. (Less)
Please use this url to cite or link to this publication:
author
Levin, Therese LU
supervisor
organization
alternative title
Linking the subjective impression of daylighting to measured daylight levels
course
AEBM01 20171
year
type
H2 - Master's Degree (Two Years)
subject
keywords
daylighting, daylight factor, subjective assessment, self-administered questionnaire, Greenhouse
language
English
id
8918170
date added to LUP
2017-06-22 12:59:18
date last changed
2017-06-22 12:59:18
@misc{8918170,
  abstract     = {What could be considered an adequate level of daylight in buildings has become a debated question in the Swedish building industry. The current daylight requirements are often found difficult to meet in practice, especially in combination with other requirements regarding energy use. Outdated daylight requirements in the national building code combined with limited knowledge about the subjective impression of daylight in residential buildings are two issues that form the bottleneck around the question of daylight and energy in buildings. Daylight is of great importance to our health and well-being. It is thus important to identify an adequate daylight level while defining an appropriate expression of this level through relevant daylight metrics in building codes and certification systems. This study focuses on the tenants’ subjective impression of the daylight conditions in the apartments of MKB Greenhouse, Malmö, Sweden. The goal of this study is to link the subjective impression of daylight to objectively measured and simulated data. This study contributes to knowledge in the field that will help to determine suitable daylight conditions in future energy efficient multi-family dwellings. Self-administered questionnaires are used to collect information about the subjective impression of daylight in Greenhouse. Physical measurements are carried out and existing daylight simulations are further analyzed and discussed in relation to both measurements and subjective assessments. The subjective assessments show that the respondents have a clear preference for daylighting and that their perception of daylight level is affected by other parameters than the daylight factor alone. The objective assessment shows that the daylight factor (DFp) varies between 0.8-1.2% in the main living spaces of the apartments. Linking the objective results to the subjective ones, the results of this study is that the objective daylight level does not correspond to the expected level of subjective satisfaction. The final conclusion is thus that a lower threshold than the current (DFp ≥ 1.2%) is not recommended.},
  author       = {Levin, Therese},
  keyword      = {daylighting,daylight factor,subjective assessment,self-administered questionnaire,Greenhouse},
  language     = {eng},
  note         = {Student Paper},
  title        = {Daylighting in environmentally certified buildings. Subjective and objective assessment of MKB Greenhouse, Malmö, Sweden},
  year         = {2017},
}