Impact of indoor environmental quality on occupant performance: A case study of residential colleges at Universiti Malaysia Perlis, Malaysia

This paper investigates the Indoor Environmental Quality (IEQ) factors influencing occupant satisfaction in commercial buildings in Iran, contrasting the views of building experts (architects and engineers) with those of building occupants. Employing the fuzzy analytical hierarchy process (FAHP), this study focuses on the four primary IEQ factors: thermal comfort, indoor air quality, visual comfort, and acoustic comfort. The study aims to bridge the gap between expert evaluations and occupant perceptions of IEQ factors in commercial buildings in Iran. By examining the disparities in prioritising IEQ factors between these two groups, the study sheds light on the complexities of IEQ assessment and highlights the importance of considering diverse perspectives in optimising indoor environments. Our methodology includes a survey conducted among 30 building experts (15 architects and 15 building engineers) and 102 occupants, employing FAHP to derive the relative importance weights of each IEQ factor. The results highlight significant disparities between architects, engineers, and occupants in prioritising these factors. Architects emphasise visual comfort (42%), while engineers and occupants view thermal comfort (53% and 41%) as the most crucial factor for occupant satisfaction. The study underscores the complexity of IEQ in commercial buildings and the diverse perspectives influencing its assessment. It contributes to the broader discourse on optimising IEQ, emphasising the need for a comprehensive approach that encompasses both technical expertise and occupant experience.

Indoor environmental quality performance and occupants’ satisfaction [IEQPOS] as assessment criteria for green healthcare building rating

In the property, design and construction industry the main focus of sustainability has been seen to affect the environmental such as climate change and resource depletion. Even though building may meet the recommended standards overall, but yet occupants still complain about several aspects. Indoor environmental quality consequently affects health, productivity and well-being of building occupants as most of them spend their time in indoor space. Therefore they are at risks for air pollutant occurs in the indoor air of dwellings such as volatile organic compounds, paints, ventilation, and others environmental pollutant. This paper reviews the potential health consequences in changes of climates change whereby developed countries contributed in energy consumption and greenhouse gas emissions. From the review search by 57 publications, the literature discussing about how thermal, acoustic and visual comfort as well as indoor air quality affects the satisfaction in indoor environmental quality and impacts to the human health. However, from the undertaken review most of the studies only highlighted on one aspects of indoor environmental quality. A number of critical aspects which give direct impacts to occupants have been identified. Subsequently, among all aspects such as lighting, ventilation, acoustics or humidity and thermal but thermal comfort perceived to influence overall satisfaction of occupants in the building. Thus, from the study revealed the critical aspects of indoor environment and contribute to the improvement for well-being and productivity of building occupants.

Editors Ayu Wazira Azhari, Naimah Ibrahim, Fahmi Muhammad Ridwan, Razi Ahmad, Norazian Mohamed Noor, Ho Li Ngee, Farrah Aini Dahalan, Ilya Joohari, Shamilah Anudai & Zulkarnain Hassan. Organiser Center of Excellence, Water Research and Environmental Sustainability Growth (WAREG), Universiti Malaysia Perlis, Perlis, MalaysiaFaculty of Civil Engineering & Technology, Universiti Malaysia Perlis, Perlis, MalaysiaSchool of Chemical Engineering and Technology, Xi’an Jiaotong University, Xi’an 710049, China Preface The International Conference on Civil and Environmental Engineering 2022 (CENVIRON2022) - Special Issue on Sustainable Environment & Communities took place on 29 – 30 August 2022 at Penang, Malaysia. The conference was jointly organized by the Center of Excellence, Water Research and Environmental Sustainability Growth (WAREG), Universiti Malaysia Perlis, the Faculty of Civil Engineering & Technology, Universiti Malaysia Perlis and School of Chemical Engineering and Technology, Xi’an Jiaotong University, Xi’an 710049, China.This conference brought together researchers, practitioners, engineers and students worldwide in hope to extend networking, integrate knowledge and exchange ideas among participants. This year, the theme “Towards safe, resilient and sustainable cities for humankind” takes an in-depth look at cutting edge research and development that address major topics in various environmental sustainability-related research. Over 70 distinguish researchers, practitioners, engineers and students from across the country have presented their current and intriguing research in the scope of civil and environmental engineering and technology, which evolved around six major areas: water protection, water resources and hydrology, technologies for water management, energy and water, air and noise and sustainable materials.The conference has gained tremendous success due to collective efforts from the organizing committees, the co-organizers, the reviewers, presenters, and all participants. Special acknowledgment goes to the keynote speakers who assent our invitation and successfully delivered interesting talks to catch all the participants’ attention. The keynote speeches were delivered by Professor Dr. Kun Guo from the School of Chemical Engineering and Technology, Xi’an Jiaotong University China with the topic “Microbial electrochemical technology for energy and resource recovery from wastewater” and Professor Ar. Dr. Abdul Razak Sapian from the Kullliyyah of Architecture and Environmental Design, International Islamic University Malaysia (IIUM), Malaysia with the topic “Madani Built Environment”We would like to thank all the reviewers involved in ensuring each contributed paper were refereed and accepted based on interests, relevance, innovation and pure contribution towards the civil and environmental engineering and technology fields. Acknowledgement and gratitude also goes to Astasoft Sdn. Bhd. and Mega Jati Academy for sponsoring this conference. Finally special thanks goes to the Universiti Malaysia Perlis for the continuous support throughout the conference event. Che Zulzikrami Azner Abidin Chairman,International Conference on Civil and Environmental Engineering 2022 (CENVIRON2022)Special Issue on Sustainable Environment & CommunitiesList of Committee is available in this pdf.

Indoor Environmental Quality (IEQ) is a concept to understand and assess occupant comfort in buildings. It is evaluated in terms of four aspects namely thermal comfort, visual comfort, acoustic comfort and indoor air quality. This study assesses the IEQ of vernacular structures and compares it to that of contemporary dwellings in a hilly village named Rakkar in Dharamshala, Himachal Pradesh. An on-field investigation of 06 houses of traditional vernacular, neo-vernacular and contemporary architectural styles was conducted which included collection & analysis of objective and subjective data. Readings of 8 environmental indicators were taken using handheld devices. Additionally, a survey of the occupants was conducted which provided insights into their experience, adaptation and satisfaction levels with respect to the four aspects of IEQ. Results indicate that for thermal comfort, neo-vernacular dwellings perform the best followed by traditional vernacular buildings due to their high thermal mass. The study also records lack of thermal comfort in cooking spaces of traditional residences due to excessive air infiltration. In terms of visual comfort, one of the contemporary structures performs the best due to its high window-to-wall ratio, but this comes at the cost of poor thermal comfort. There are differences in objective readings of acoustic environment and indoor air quality in the 3 typologies, but they are found to be within acceptable limits as per Indian & international standards, and the occupants are generally satisfied in terms of aural comfort & IAQ. Findings from this research provide insights into the building envelope parameters that contribute to a good indoor environment. These building attributes can be used to design energy efficient buildings that enhance occupant comfort, thereby consuming less energy during their operational life.

Purpose Despite the increased retrofitting of Finnish residential buildings, there are limited post-retrofit studies on the actual measured indoor environmental quality (IEQ) and occupant satisfaction during summer-time. This paper provides a better understanding of the actual performance of retrofitted residential apartment buildings in Finland, focusing on some aspects of and the risk of summer overheating through post-occupancy evaluation (POE). Design/methodology/approach The study used both qualitative and quantitative data collection methods, including satisfaction surveys, indoor air temperature and relative humidity measurements, self-reported behaviour forms, open-ended discussions, and site visits in five apartments in different residential buildings in Tampere city, monitored during the summer-time, for at least 2 weeks at a time. Findings While occupants were positive regarding most aspects of IEQ, concerns about indoor air quality (IAQ), summer overheating and acoustic comfort were raised. The summer-time monitoring highlighted that indoor air temperatures could reach as high as 27 °C for 2–9 days depending on the monitored apartment. Little cloud cover and warmer outdoor temperatures directly influenced indoor air temperature overheating. For some aspects of the investigated IEQ parameters, it was noted that while occupants’ satisfaction was influenced by the length of their residence, their acceptance of the same conditions remained positive over time (i.e. more than one year) as they adapted over time. Research limitations/implications The number of participants and case studies was relatively small due to the well-known difficulty in gaining access to private homes, so the results do not allow generalisation but do provide interesting insights of these specific cases to be validated with future additional research. The short sequential rather than long-term parallel monitoring of the case study apartments was another limitation making comparison between cases and understanding reasons for differences difficult. Practical implications Findings highlight the need to maintain the performance of housing in Finland during summer-time. The highlighted subjective issues emphasised in this study underscore the necessity for enhanced pre- and post-retrofit quality processes and the prompt resolution of issues as they arise. The integration of POE studies into all residential construction practices becomes pivotal for the advancement of sustainable homes now, but also in the future, especially when subjected to a warming climate. Originality/value This study is among the few POE studies conducted in Finland, offering insights into post-retrofit performance and occupant satisfaction during the summer-time. The study highlights the potential of POE to understand the performance of retrofitted Finnish apartments from a user-centric perspective.

Multi-domain indoor environmental quality in buildings: A review of their interaction and combined effects on occupant satisfaction

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.

Satisfaction of occupants toward indoor environment quality of certified green office buildings in Taiwan

Are Building Occupants Satisfied with Indoor Environmental Quality of Higher Education Facilities?

Indoor Environmental Quality (IEQ) significantly affects occupants’ well-being and comfort. Assessing IEQ typically involves post-occupancy evaluation (POE), a method that can be time-consuming and particularly challenging in hotel settings, where guests may be disrupted by frequent requests for feedback. Hence, this paper investigates the capability of text mining to extract valuable information for IEQ assessment, such as identifying the main causes of IEQ dissatisfaction, detecting combined occurrences of IEQ aspects, and exploring the relationship between IEQ dissatisfaction and hotel attractiveness. To this aim, the study analysed 1494 five-star hotels in Europe, comprising 515,738 reviews. Among them, 13.1% contained references to keywords related to IEQ aspects. The major cause of dissatisfaction in hotels is acoustic (42.7% of the reviews), followed by thermal (35.7%), visual (11.1%) comfort, and IAQ (10.5%). Additionally, 9580 reviews demonstrated the co-occurrence of multiple IEQ aspects, highlighting the interplay between different aspects. Furthermore, the reviewer score, reflecting the hotel’s attractiveness, showed an inverse relationship with the percentage of dissatisfied guests regarding IEQ, highlighting the impact of the indoor environment on the hotel rating. Overall, text mining is effective in supporting IEQ assessment and the study underscores the effect of addressing IEQ aspects on a facility's overall appeal.

Indoor environment quality is a relative measure of comfort perception by people exposed to the indoor conditions. It is expected that any assessment of energy performance should also include indoor comfort. This study is to review indoor environmental quality models (with respect to thermal and acoustic comfort, indoor air and lighting quality). A simplified indoor environmental quality model is also developed with consideration of EN 15251 draft ‘Guideline for using indoor environmental input parameters for the design and assessment of energy performance of buildings’. This article analyses what components should be modelled and in particular discusses the effect of different weighting schemes on the overall indoor environmental quality index. The analysis includes thermal comfort models, indoor air quality, acoustic comfort and daylight illumination versus lightning. The proposed indoor environmental quality component sub-models will give the most reliable results when the model indoor environment input data are correctly measured and disturbing influences of indoor environmental quality monitoring process are well defined and properly assessed. The final indoor environmental quality result is based on subjoining the uncertainty values achieved in panel analysis of percentage of persons dissatisfied with indoor environmental quality with corrected measurement uncertainty. All simulations for IEQindex sub-components and preliminary metrological analysis of the whole indoor environmental quality model were performed with the NIST program for Monte Carlo tests. The presented indoor environmental quality model proposal is developed to support engineers’ practice as the convenient tool for a practical assessment of building’s occupational satisfaction.

A higher educational student spends around 3-8 years in institutional buildings. Thus, it is of a prime importance to maintain proper Indoor Environmental Quality (IEQ) in lecture theatres in higher educational institutions as inadequate IEQ will lead to Sick Building Syndrome (SBS) and Building Related Illnesses (BRI). When it comes to the Sri Lankan context, there are only limited studies done on assessing the IEQ in institutional buildings. Therefore, the purpose of this research is to assess the IEQ of lecture halls by considering various parameters such as indoor air quality, thermal comfort, visual comfort and acoustic comfort for mechanically ventilated lecture halls. This study has investigated whether IEQ of the higher education facilities complies with the American society of heating, refrigerating and air-conditioning engineers (ASHRAE) standard which is the current standard we are using in Sri Lanka for the IEQ assessment. The study has also performed a qualitative assessment of the IEQ through questionnaire surveys with the students and assessed whether it there is a co-relation with the IEQ and SBS. Five different lecture theatres of different indoor environmental conditions at University of Sri Jayewardenepura, Faculty of Applied Sciences premises were selected to carry out the investigation. Different IEQ parameters such as thermal comfort, indoor air quality, visual comfort and acoustic comfort were measured with using specific instruments. Quantitative data collection was done throughout a semester and qualitative data collection was done using a questionnaire. A statistical data analysis was conducted to assess whether there are co-relations between the IEQ and the SBS symptoms for the particular lecture halls.The results have shown that some of the lecture theatres have exceeded standard values of indoor CO2 levels when compared to the ASHRAE standards. However, it could be improved by allocating the students with the proper occupant density.There were some disturbances to the acoustic comfort in certain lecture halls due to some ventilation machineries. The results of this study could be used for the future improvements in designing of the lecture theatres for the higher education facilities in Sri Lanka. Keywords: Indoor environmental quality (IEQ), Sick building syndrome (SBS), Building related illnesses (BRI)

This study examines the impact of Indoor Environmental Quality (IEQ) on guest comfort and satisfaction in former Green Building Index (GBI)-certified green hotels in Malaysia’s historic cities, including Kuala Lumpur, Melaka, and Penang. With many hotels moving away from certification, it highlights the need to maintain high environmental and comfort standards. The research evaluates IEQ performance, suggests additional parameters, and explores how comfort mediates the relationship between IEQ and satisfaction. Eight hypotheses were tested, focusing on indoor air quality (IAQ), thermal comfort, lighting, acoustics, visual comfort, building features, decoration, and indoor greenery. A survey of 700 hotel guests resulted in 384 valid responses, confirming that IEQ significantly influences comfort and satisfaction. Among the factors, acoustic/noise (Beta = 0.305), IAQ (Beta = 0.221), and building characteristics (Beta = 0.167) were the most impactful, followed by thermal comfort, lighting, decoration, visual comfort, and indoor greenery. Regression analysis showed a strong link between guest comfort and satisfaction, with comfort as a key mediator. Challenges included noise, thermal discomfort, and lighting problems. The study emphasizes the importance of air quality, thermal comfort, and noise management while balancing aesthetic elements like greenery and decoration to improve guest experiences. It offers valuable insights for hotel operators, advancing sustainable practices and guest satisfaction in green-certified hotels.

Implementing sustainable construction practices in higher educational facilities in Malaysia would enhance the quality of learning activities. Students in higher education predominantly utilize learning areas. The objective of this study is to evaluate indices of indoor environmental quality (IEQ) that prioritise sustainability in educational environments. The major indicators comprised four significant key terms: Indoor Air Quality (IAQ), Thermal Comfort (TC), Visual Comfort (VC), and Acoustic Comfort (AC). The study utilized data from previous studies published between 2021 and 2023 to determine the present issue that emerged inside Malaysian higher educational facilities. This was achieved by a critical assessment of the parameters' findings via fieldwork measurement. This leads to a spectrum that falls within a satisfactory threshold to attain the desired degree of user comfort. The findings demonstrate that students' comfort level is enhanced by their preference for a stable level of IEQ parameters. According to this study, on average standards of IEQ parameters for a sustainable learning environment; temperature (27°C), humidity (40%), air flow (0.30 m/s), illuminate (400lux) and acoustic (40dB). The strategic framework has been recommended to enhance learning environments and act as a reference guideline for future evaluations of indoor environmental quality.