Abstract

Globally, a primary concern is whether green office buildings perform as promised in terms of providing better indoor environment quality (IEQ) for employees, which may affect their satisfaction and work performance. In the Middle East, although there has been renewed interest in green building design, post occupancy evaluation of performance has never been conducted to-date, and evidence of actual occupant perception in green and non-green buildings is still ambiguous. Hence, we present the first study on IEQ performance in the Middle East. We show that Jordan can be taken as a representative example and systematically compare five “green” office buildings (representing 71% of all green-certified office buildings) against eight comparable conventional office buildings (CBs). Detailed bi-lingual survey data on perceived IEQ (n = 502) and work performance are accompanied by high-resolution continuous physical measurements of air temperature + relative humidity (n = 83) and CO2 concentrations (n = 21) with periodic measurements of mean radiant temperature and air speed, covering two typical summers and one typical winter. Results show both buildings types comply with design standards for indoor CO2 levels, while thermal comfort in green buildings is better than in CBs. However, CBs have a higher overall occupant satisfaction of IEQ. Work performance measured as absolute and relative absenteeism was slightly higher in CBs, with no significant differences in relative and absolute presenteeism between the two buildings types. These findings challenge the notion that green buildings improve occupant satisfaction and work performance over CBs and suggest the need for a better understanding of the performance-satisfaction gap.

Highlights

  • Buildings consume 48% of global energy, and they are responsible for a quarter of global carbon emissions (IEA 2019)

  • The thermal sensation vote (TSV) were compared to the ANSI/ASHRAE 55 (2017) comfortable range of [-1, +1], and predicted mean vote (PMV) were compared to ISO 7730 (2005) comfort range of [−0.5, +0.5], a comparison between TSVs and PMVs was conducted in both buildings types

  • Mean CO2 concentration levels were compared according to the building type, and secondly, the average fraction of the day within the LEED limit of 1100 ppm was appraised (Figure 5) (ANSI/ASHRAE 62.1 2019)

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Summary

Introduction

Buildings consume 48% of global energy, and they are responsible for a quarter of global carbon emissions (IEA 2019). There is no formal definition of this term, a “green building” conventionally refers to a building that is designed to be efficient in the consumption of natural resources, while conserving energy, reducing harmful impact on the environment, and improving quality of life for users (EPA 2019) This resulted in the creation of several building design standards all over the world, but of which the earliest, i.e. BREEAM (Building Research Establishment Environmental Assessment Method) established in 1990 in the United Kingdom (BREEAM 2019), and LEED (Leadership in Energy and Environmental Design) launched in 1998 in the United States (USGBC 2019), are the most widespread, being used in 70 and 162 countries respectively. Office buildings are the largest single category of LEED buildings globally, representing

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