Task lighting effects on office worker satisfaction and performance, and energy efficiency

Abstract

/npsi/ctrl?lang=en http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?lang=fr Access and use of this website and the material on it are subject to the Terms and Conditions set forth at http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/jsp/nparc_cp.jsp?lang=en NRC Publications Archive Archives des publications du CNRCThis publication could be one of several versions: author's original, accepted manuscript or the publisher's version. / La version de cette publication peut être l'une des suivantes : la version prépublication de l'auteur, la version acceptée du manuscrit ou la version de l'éditeur. For the publisher's version, please access the DOI link below./ Pour consulter la version de l'éditeur, utilisez le lien DOI ci-dessous.http://dx.doi.org/10.1582/LEUKOS.2004.01.04.001 Leukos, 1, 4, pp. 7-26, 2005-04-01 Task lighting effects on office worker satisfaction and performance, and energy efficiency Newsham, G. R.; Arsenault, C. D.; Veitch, J. A.; Tosco, A. M.; Duval, C. L. ABSTRACTThis paper reports on two experiments conducted in the same office laboratory. As part of a larger experiment, 58 participants worked for a day under one of two lighting designs. The first design used ceiling-recessed parabolic luminaires only; the second design employed the same parabolic ambient lighting, with the addition of an angle-arm task light. Participants had no control over the lighting until the afternoon, when they were offered dimming control over the ambient parabolic lighting; participants with task lighting were also permitted to move the arm location. During the day participants performed a variety of simulated office tasks, as well as completing a number of questionnaires on mood, satisfaction, and discomfort. There was no main effect of lighting design on questionnaire outcomes, however, task lighting was associated with performance improvements on some tasks. Interestingly, provision of a task light did not lower participants' preferred ambient light output.The second experiment, with 31 participants, followed up on this final point. Again, ambient lighting was provided by ceiling-recessed, parabolic luminaires, and participants were provided with a task light. For two task light types (angle-arm and luminous shade) at three different levels of output (0%, 50%, and 95%), participants used a dimmer to select their preferred level of ambient lighting. Increasing task lighting did reduce chosen ambient light output, but the reduction in lighting power was small, and only about the same as the power drawn by the task light. Results suggested that participants did not dim ambient lighting further because they preferred to maintain illumination on non-task surfaces, and to avoid extreme luminance ratios.

Intellectual productivity under task ambient lighting

“…Task ambient (TA) lighting can reduce energy consumption by combining a low uniform lighting system and a local lighting system instead of conventional uniform lighting systems while maintaining the light levels around working spaces. Previous studies 1,2 have revealed that TA lighting is also effective in increasing worker satisfaction and productivity. However, evaluations in previous studies were based mainly on questionnaires (subjective evaluation) and/or simulated office tasks, which might be greatly affected by a learning effect.…”

Smart Desks to Promote Comfort, Health, and Productivity in Offices: A Vision for Future Workplaces

“…For instance, the user might hunch or move closer to the task while trying to read text that is affected by glare, reflection or poor contrast (Joines et al, 2015). Proper task lighting can help mitigate these negative effects on the posture, eye strain and visual comfort of the user (Newsham et al, 2005;Joines et al, 2015). Furthermore, studies have linked exposure to blue light during night to disruption in the circadian rhythm and increased risk of breast and colorectal cancer (Stevens, 2009;James et al, 2016).…”

Energy-Related Occupant Behaviour and Its Implications in Energy Use: A Chronological Review

“…The relationship between task lighting on occupant's mood, satisfaction, and performance and its correlation to energy savings, using as reference illuminance values, as suggested by Green Star (Green Building Council of Australia-GBCA) and Illuminating Engineering Society of North America (IESNA) allowed for concluding that there was no direct association among these variables [33]. On the contrary, when comparing the actual energy intensity use to the baseline model of seven offices or libraries buildings, and four multi-family residential buildings certified by the green building certification tool LEED (Leadership in Energy and Environmental Design), it was possible to conclude that almost all of the buildings had savings of over 40%, when compared to the design model projections, but there was no clear relationship between occupant satisfaction in comfort temperature and the building energy intensity [34].…”