Indoor environmental quality and occupant satisfaction in green-certified buildings

Green building certification systems aim at improving the design and operation of buildings. However, few detailed studies have investigated whether green rating leads to higher occupant satisfaction with indoor environmental quality (IEQ). This research builds on previous work to address this. Based on the analysis of a subset of the Center for the Built Environment Occupant Indoor Environmental Quality survey database featuring 11,243 responses from 93 LEED-rated office buildings, we explored the relationships between the points earned in the IEQ category and the satisfaction expressed by occupants with the qualities of their indoor environment. We found that the achievement of a specific IEQ credit did not substantively increase satisfaction with the corresponding IEQ factor, while the rating level, and the product and version under which certification had been awarded, did not affect workplace satisfaction. There could be several reasons for this lack of relationships, some of which are outside the control of designers and beyond the scope of rating systems based primarily on design intent. We conclude with a discussion of the challenges and priorities that building professionals, researchers, and green building certification systems need to consider for moving us towards more comfortable, higher performing, and healthier green-rated buildings

Exercised control, lighting choices, and energy use: an office simulation experiment

The belief that individual control leads to beneficial behavioural outcomes underlies many recommendations to install individual controls for workplace lighting, temperature, and ventilation in workplaces. The present experiment compared the work performance and satisfaction of 47 office workers who were given choices concerning workplace lighting (CS) with age- and sex-matched partners (PP) who were given no choices but worked under identical lighting. Preferred luminous conditions were recorded for both groups. Satisfaction with lighting and the work environment were high for both groups, and the majority of participants chose lighting conditions consistent with current codes and standards for lighting, including energy use. CS participants had greater perceived control than PP participants, but there were no differences in satisfaction, mood, performance or health. PP participants' lighting choices, recorded at the end of the day-long session, created less VDT glare than CS choices. Although there was no short-term benefit of perceived control over lighting, it appears that experience with workplace conditions could lead to the ability to reduce unpleasant conditions if choices were available.Nombreuses sont les recommandations visant l'installation de commandes individuelles d'\ue9clairage, de temp\ue9rature et de ventilation dans les lieux de travail, recommandations qui d\ue9coulent de l'hypoth\ue8se selon laquelle l'utilisation de commandes individuelles par les employ\ue9s entra\ueenerait chez ces derniers une am\ue9lioration du comportement. L'exp\ue9rience dont il est question ici visait \ue0 comparer le rendement et la satisfaction au travail de 47 employ\ue9(e)s de bureau qui pouvaient r\ue9gler l'\ue9clairage dans le lieu de travail (CS) \ue0 ceux de partenaires du m\ueame \ue2ge et du m\ueame sexe (PP) qui ne pouvaient r\ue9gler cet \ue9clairage et devaient donc travailler dans des conditions identiques. On a enregistr\ue9 les conditions d'\ue9clairage privil\ue9gi\ue9es par les deux groupes. Chaque groupe a affich\ue9 un degr\ue9 de satisfaction \ue9lev\ue9 concernant l'\ue9clairage et l'environnement de travail, et les participants ont choisi pour la plupart des conditions d'\ue9clairage conformes aux codes et normes actuels en mati\ue8re d'\ue9clairage, y compris les aspects de consommation d'\ue9nergie. Les participants CS ont \ue9prouv\ue9, bien s\ufbr, un sentiment de ma\ueetrise de la situation sup\ue9rieur \ue0 celui des participants PP, mais le degr\ue9 de satisfaction, l'humeur, le rendement et la sant\ue9 ont \ue9t\ue9 pratiquement identiques chez les deux groupes. Les choix d'\ue9clairage des participants PP, not\ue9s \ue0 la fin de la longue journ\ue9e de travail, ont produit moins de reflets aux terminaux \ue0 \ue9cran que ceux des participants CS. Bien qu'il ne semble y avoir aucun avantage \ue0 court terme au sentiment de ma\ueetrise de la situation en ce qui concerne l'\ue9clairage, on peut conclure, \ue0 la lumi\ue8re de cette exp\ue9rience sur les conditions en milieu de travail, que les choix peuvent donner lieu \ue0 une am\ue9lioration de ces conditions.Also presented at American Psychological Association 106th Annual Convention, San Francisco, August 1998.Peer reviewed: YesNRC publication: Ye

Determinants of lighting quality I: state of the science

Lighting quality may be the most talked about but least understood concept in lighting research and lighting design. Interest in lighting quality is currently high, judging from the occurrence of sessions and workshops a almost all major conferences (e.g., at the Commission Internationale de l'\uc9clairage session in New Delhi, India, in November 1995; at the Chartered Institute of Building Services Engineers 1996 National Lighting Conference in Bath, England, in March 1996; and at LIGHTFAIR INTERNATIONAL, in San Francisco, May 1996). The introduction of building energy codes and pressure to increase energy-efficiency has re-opened an old debate.Also presented at the Illuminating Engineering Society of North America 1996 Annual Conference, Cleveland, OH, U.S.A., August 1996Peer reviewed: YesNRC publication: Ye

Lighting quality recommendations for VDT offices: a new method of derivation

This paper provides a new method of deriving lighting quality recommendations for visual display terminal (VDT) offices. An experiment in a mock-up office space gave occupants control over dimmable lighting circuits after a day working under pseudo-random lighting conditions. It examines whether lighting experienced during the day influenced the changes in lighting made at the end of the day and it derives preferences for luminance ratio.Ce document d\ue9crit une nouvelle m\ue9thode permettant de puiser des recommandations concernant la qualit\ue9 de l'\ue9clairage pour des bureaux \ue9quip\ue9s de terminaux \ue0 \ue9cran. Dans le cadre d'une exp\ue9rience men\ue9e dans une surface de bureaux simul\ue9e, on a procur\ue9 aux occupants le contr\uf4le de circuits d'\ue9clairage \ue0 intensit\ue9 r\ue9glable au bout d'une (1) journ\ue9e de travail en conditions d'\ue9clairage pseudo-al\ue9atoires. On y examine la question de savoir si l'\ue9clairage durant le jour influe ou non sur les changements qui y \ue9taient apport\ue9s \ue0 la fin de la journ\ue9e, et des pr\ue9f\ue9rences sont d\ue9duites en mati\ue8re de rapport de luminance.Peer reviewed: YesNRC publication: Ye

Experts' quantitative and qualitative assessments of lighting quality

As part of ongoing lighting quality research, lighting experts in design and research were given the opportunity to judge the lighting quality of nine lighting designs for a windowless open-plan office. The nine lighting conditions are defined by a 3 x 3 matrix of levels of lighting power density and lighting quality as defined by designers (designers' lighting quality, DLQ). The nine lighting designs were created by a panel of Canadian lighting designers and illuminating engineers, who provided the initial definitions of low, medium, and high DLQ for typical contemporary mid-grade offices. Renderings of the space as it would appear in each condition were created using Radiance (TM). Packages including ceiling layouts, equipment specifications, photometric data, illuminance calculations, and colour photocopies of the renderings were mailed to forty lighting experts in North America, Europe, Australia, and New Zealand. The experts rated the appearance of the space on five semantic differential scales and then rated its overall lighting quality on a scale of 1 to 9. Agreement about the lighting quality of the designs was poor, but improved when the data from North Americans and Non-North Americans were examined separately. The results are discussed in terms of their implications for the development of standards and for future research.Dans le cadre des travaux de recherche sur la qualit\ue9 de l'\ue9clairage en cours, les experts en \ue9clairage tant au point de vue de la conception que de la recherche ont eu l'occasion de juger la qualit\ue9 de neuf types d'\ue9clairage pour un bureau en espace fonctionnel sans fen\ueatre. Les neuf conditions d'\ue9clairage sont d\ue9finies \ue0 l'aide d'une matrice 3 x 3 repr\ue9sentant diverses combinaisons de niveaux de densit\ue9 de puissance lumineuse (DPL)et de qualit\ue9 \uab concepteur \ubb de l'\ue9clairage (QC\uc9). Les neuf types d'\ue9clairage ont \ue9t\ue9 cr\ue9\ue9s par un groupe de concepteurs et d'ing\ue9nieurs \ue9clairagistes canadiens, qui ont donn\ue9 les d\ue9finitions initiales d'une QC\uc9 faible, moyenne et \ue9lev\ue9e pour des bureaux actuels de moyenne grandeur. Les rendus de l'espace comme il appara\ueetrait dans chaque condition ont \ue9t\ue9 cr\ue9\ue9s \ue0 l'aide de RadianceMc. Des trousses comprenant les plans du plafond, les sp\ue9cifications du mat\ue9riel, les donn\ue9es photom\ue9triques, les calculs des niveaux d'\ue9clairement et les photocopies couleur des rendus ont \ue9t\ue9 envoy\ue9s \ue0 quarante experts en \ue9clairage d'Am\ue9rique du Nord, d'Europe, d'Australie et de Nouvelle-Z\ue9lande. Les experts ont \ue9valu\ue9 l'aspect de l'espace selon cinq \ue9chelles s\ue9mantiques diff\ue9rentielles et ont ensuite class\ue9 la qualit\ue9 globale de l'\ue9clairage sur une \ue9chelle de 1 \ue0 9. Les r\ue9sultats sur la qualit\ue9 de l'\ue9clairage des divers mod\ue8les ont \ue9t\ue9 disparates, mais ont paru mieux concorder quand les donn\ue9es provenant des nord-am\ue9ricains et des autres ont \ue9t\ue9 examin\ue9es s\ue9par\ue9ment Les r\ue9sultats sont \ue9tudi\ue9s en ce qui a trait \ue0 leur importance pour l'\ue9laboration de normes et pour la recherche future.Peer reviewed: YesNRC publication: Ye

Determinants of lighting quality II : research and recommendations

ERIC Document Reproduction Service No. ED408543Peer reviewed: YesNRC publication: Ye

A New method of deriving illuminance recommendations for VDT offices

This paper suggests a new method of objectively deriving illuminance recommendations for VDT offices. An experiment in a mock-up office space gave occupants control over dimmable lighting circuits after a day working under constant, pseudo-random lighting conditions (for example, desktop illuminance during the day varied between 100 to 700 lux). Data analysis indicated that the lighting experienced during the day influenced the changes in lighting made at the end of the day. Many occupants chose to reduce screen glare if any existed. Even after statistically removing the effect of glare, those exposed to lower illuminances during the day chose higher illuminances at the end of the day, and those exposed to higher illuminances during the day chose lower illuminances. Regression of these end-of-day preferences relative to the illuminance experienced during the day can yield a preferred illuminance, equivalent to the daytime illuminance at which no change was preferred at day's end. Using this method, preferred illuminances in the range 200 to 500 lx were derived. Further, the deviation between participants' lighting preferences and the lighting they experienced during the day was a significant predictor of participant mood and satisfaction.Ce document sugg\ue8re une nouvelle m\ue9thode permettant de calculer objectivement les recommandations li\ue9es \ue0 l'\ue9clairement lumineux pour les bureaux \ue0 terminaux \ue0 \ue9cran. Lors d'une exp\ue9rience men\ue9e dans un mod\ue8le d'espace de bureau en vraie grandeur, on a donn\ue9 aux occupants la possibilit\ue9 de moduler (contr\uf4ler) des circuits d'\ue9clairage \ue0 intensit\ue9 r\ue9glable apr\ue8s une journ\ue9e de travail en conditions d'\ue9clairage constant et pseudo-al\ue9atoire. (\uc0 titre d'exemple, l'\ue9clairement du plan de travail durant le jour variait de 100 \ue0 700 lux.) Selon l'analyse des donn\ue9es, l'\ue9clairage \ue9prouv\ue9 durant le jour influait sur les changements apport\ue9s \ue0 l'\ue9clairage \ue0 la fin de la journ\ue9e. De nombreux occupants ont d\ue9cid\ue9 de r\ue9duire l'\ue9blouissement face \ue0 l'\ue9cran, le cas \ue9ch\ue9ant. M\ueame une fois \ue9limin\ue9 statistiquement le facteur de l'\ue9blouissement, les occupants expos\ue9s \ue0 des niveaux d'\ue9clairement plus faibles durant le jour ont opt\ue9 pour des \ue9clairements plus intenses \ue0 la fin de la journ\ue9e, et ceux expos\ue9s durant le jour \ue0 un \ue9clairement plus intense ont choisi des niveaux plus bas. La r\ue9gression de ces pr\ue9f\ue9rences \ue0 la fin du jour par rapport aux niveaux d'\ue9clairement v\ue9cus pendant le jour peut g\ue9n\ue9rer un \ue9clairement lumineux pr\ue9f\ue9rentiel, \ue9quivalant au niveau de jour auquel nul changement n'\ue9tait pr\ue9f\ue9r\ue9 \ue0 la fin de la journ\ue9e. Cette m\ue9thode a permis de calculer des niveaux d'\ue9clairement lumineux pr\ue9f\ue9rentiels de l'ordre de 200 \ue0 500 lx. En outre, l'\ue9cart entre les pr\ue9f\ue9rences des participants en mati\ue8re d'\ue9clairage et les niveaux auxquels ils \ue9taient expos\ue9s durant le jour s'est r\ue9v\ue9l\ue9 \ueatre une variable explicative appr\ue9ciable de l'ambiance et de la satisfaction \ue9prouv\ue9es par les participants.Peer reviewed: YesNRC publication: Ye

Investir dans l'\ue9clairage des bureaux : des retomb\ue9es pour les employ\ue9s et pour l'environnement

Fluorescent lighting arranged in regular arrays of recessed fluorescent lamps, which once passed muster as good, even excellent office lighting, nowadays causes interfering glare on computer screens. (Over the years, people have come to work differently: from paper on horizontal surfaces to vertical computer screens.) The results of an experiment with people working under various lighting conditions in an office reveal that people work more productively and with less eye strain under fluorescent lamps that have an electronic ballast. And more productively yet with certain types of louvers and certain combinations of ambient and task lighting.L'\ue9clairage fluorescent constitu\ue9 de rang\ue9es r\ue9guli\ue8res de luminaires encastr\ue9s, consid\ue9r\ue9 autrefois comme un bon, voire un excellent \ue9clairage pour les bureaux, produit aujourd'hui un reflet g\ueanant sur les \ue9crans d'ordinateur (au fil des ans, la fa\ue7on de travailler a chang\ue9 : du papier pos\ue9 \ue0 plat sur une surface horizontale, on est pass\ue9 aux \ue9crans d'ordinateur verticaux). Les r\ue9sultats d'une exp\ue9rience faite sur des personnes travaillant dans un bureau dans diff\ue9rentes conditions d'\ue9clairage r\ue9v\ue8lent que lesdites personnes sont plus productives et ressentent une moins grande fatigue oculaire sous des lampes fluorescentes qui contiennent un ballast \ue9lectronique. La productivit\ue9 \ue9tait encore accrue avec certains types de diffuseurs et certaines associations d'\ue9clairage direct et indirect.Also available in English: Office lighting investments: payoffs for people and the environmentPeer reviewed: NoNRC publication: Ye

Office lighting investments : payoffs for people and the environment

Fluorescent lighting arranged in regular arrays of recessed fluorescent lamps, which once passed muster as good, even excellent office lighting, nowadays causes interfering glare on computer screens. (Over the years, people have come to work differently: from paper on horizontal surfaces to vertical computer screens.) The results of an experiment with people working under various lighting conditions in an office reveal that people work more productively and with less eye strain under fluorescent lamps that have an electronic ballast. And more productively yet with certain types of louvers and certain combinations of ambient and task lighting.L'\ue9clairage fluorescent constitu\ue9 de rang\ue9es r\ue9guli\ue8res de luminaires encastr\ue9s, consid\ue9r\ue9 autrefois comme un bon, voire un excellent \ue9clairage pour les bureaux, produit aujourd'hui un reflet g\ueanant sur les \ue9crans d'ordinateur (au fil des ans, la fa\ue7on de travailler a chang\ue9 : du papier pos\ue9 \ue0 plat sur une surface horizontale, on est pass\ue9 aux \ue9crans d'ordinateur verticaux). Les r\ue9sultats d'une exp\ue9rience faite sur des personnes travaillant dans un bureau dans diff\ue9rentes conditions d'\ue9clairage r\ue9v\ue8lent que lesdites personnes sont plus productives et ressentent une moins grande fatigue oculaire sous des lampes fluorescentes qui contiennent un ballast \ue9lectronique. La productivit\ue9 \ue9tait encore accrue avec certains types de diffuseurs et certaines associations d'\ue9clairage direct et indirect.Aussi disponible en fran\ue7ais : Investir dans l'\ue9clairage des bureaux: des retomb\ue9es pour les employ\ue9s et pour l' environnementPeer reviewed: NoNRC publication: Ye