Indoor Environmental Quality Acceptance Research Articles

Occupants’ mood states in evaluating indoor environmental quality (IEQ) acceptance

Previous studies have developed many models for indoor environmental quality (IEQ) assessment. However, almost none of them included mood states that could impact occupants’ IEQ perceptions significantly. This study developed an IEQ acceptance model that considers occupants’ perception of thermal comfort, visual quality, and acoustic quality, as well as their mood as an additional IEQ parameter. The model constants are evaluated by a Bayesian approach with the prior estimates determined from seven existing IEQ models including 4 parameters (without mood). Two hundred fifty-nine students’ perceptions against the five parameters collected in a university library were used as the observed data to update the prior beliefs. The results indicated that involving mood in the IEQ acceptance model could improve the model's accuracy more significantly. Additionally, the updated IEQ acceptance model estimated that students with positive moods are more likely to accept the overall IEQ than those with negative or neutral moods.

Adaption and Tolerance in Built Environment—An Evaluation of Environmental Sensation, Acceptance and Overall Indoor Environmental Quality (IEQ) in a Subtropical Region

The relationship between environmental sensations and acceptance in the indoor environment has yet to be fully explored or quantified. This study is the first in the literature that examines these relationships in thermal comfort, indoor air quality, aural comfort, visual comfort, and overall indoor environmental quality (IEQ). Using a regional IEQ database, the relationship between occupants’ sensation and acceptance of individual environmental aspects was investigated. The results suggest that building occupants had high tolerances towards indoor air quality and aural and visual discomforts, while cold sensations tended to elicit environmental discomfort. Furthermore, the study developed machine learning models with imbalanced data treatment to predict overall IEQ acceptance based on both sensation and acceptance of individual IEQ domains. These models accounted for the influence of environmental adaptation and tolerance on overall IEQ satisfaction determination. They accurately predicted unseen data, indicating high model generalizability and robustness. Overall, the study has practical implications for improving building performance and provides insights to better understand the relationship between environmental sensations and occupants’ acceptance, which should be considered in building design and operation.

Commercial building indoor environmental quality models: A critical review

Indoor environmental quality (IEQ) models merge various influencing IEQ factors into a single overall indicator. The outcome of the IEQ model is usually a numerical rating or score that provides an evaluative summary of the IEQ performance. Many publications have developed IEQ models from their field measurement and/or satisfaction survey results, however with distinct measurement protocols, IEQ weighting schemes and analytical methods. This paper presents a comprehensive review of 25 studies focusing on developing IEQ evaluation models in commercial buildings. Two IEQ measurement approaches (objective and subjective measurement), and three types of IEQ models—subjective-objective models, objective models and subjective models—are first differentiated. Five commonly used analytical methods (linear regression, non-linear regression, analytical hierarchy process, ensemble averaging method, and updated IEQ acceptance model) are discussed. The interaction effects between IEQ factors and relative contribution of them to the overall IEQ satisfaction are also assessed. Twenty-five studies are then mapped by data collection method, analytical method and number of survey responses. Five key criteria for developing quality IEQ models—number of IEQ factors included, spatial and temporal variability in physical measurement, analytical methods for model development, and the number of responses if subjective surveys are carried out—are proposed and discussed. A simple ranking and scoring system is propounded for evaluating the quality of the IEQ models developed in the reviewed studies. Results show that two studies achieved a total score equal to or higher than 80% of the total score, and 16 studies achieved a minimum of 60% of the total score. This tool can help researchers quickly assess the accuracy and reliability of IEQ models developed from diverse methods and make an informed decision.

Gender-related differences in perceived productivity and indoor environmental quality acceptance. Results of a questionnaire survey in university workplaces

Improving occupant's satisfaction represents an important target oriented both towards the increment of productivity and towards the reduction of operational costs related to health and safety of employees. These considerations are the bases of an interdisciplinary cross-country survey on the human-building interaction in office buildings. The proposed study presents findings from the survey conducted at the University of Calabria (Italy). In particular, both demographic characteristics of the sample and data regarding comfort, satisfaction, and productivity are processed and investigated. Descriptive statistical analysis is developed with the aim of highlighting the influence of indoor comfort conditions on the perceived productivity of employees. Particular attention is dedicated to the study of gender-related differences in internal environment perception. Indoor temperature, quality of indoor air, and acoustics are the most selected causes of dissatisfaction and low perceived productivity both for women and men. The responses regarding satisfaction level and perceived productivity are also combined by defining a quantitative indicator named Office Productivity and Satisfaction index (OPSi) that is the ratio between the perceived productivity and the satisfaction level of the considered comfort condition. Causes of discomfort are also analyzed and demonstrated gender-related differences in workplaces quality evaluation.

An open acceptance model for indoor environmental quality (IEQ)

Indoor environmental quality (IEQ) acceptance prediction is crucial to sustainable building development. A simple yet comprehensive IEQ modelling strategy that can genuinely reflect occupant's responses to environmental conditions is necessary. This study proposes an open acceptance model that uses frequency distribution functions of occupant's responses towards IEQ parameters to assess IEQ. The proposed model is not only flexible enough to encapsulate a diverse range of descriptive model parameters but also feasible for openly available IEQ acceptance data, offering the flexibility to add data incrementally to allow easy model updating as and when a new set of observations arrives, this model can be a solution to the existing problems and limitations encountered in IEQ modelling.

Evaluation of an indoor environmental quality model for very small residential units

This study investigates the indoor environmental quality (IEQ) responses from occupants living in very small residential units that are unique to Hong Kong. Through the changes in environmental parameters, including thermal, indoor air quality, visual and aural, the study demonstrates that the overall IEQ acceptance in these units is different from the one in general residential building environments. Results show that occupants of these units are more sensitive to warmth and operative temperature change as compared to occupants of general residential buildings. A small variation of thermal acceptance suggests that the small unit occupants have already developed certain degree of tolerance to hot conditions. The adaptation to the reality of a hot environment is also reflected in the overall IEQ acceptance. It is believed that very small space residents have developed tolerance and adaptation to an unchangeable reality, changing environmental conditions does not necessarily alter their acceptance of individual IEQ aspects and overall IEQ.

Indoor Environmental Quality of Air Conditioned Residential Buildings in Extreme Dry Desert Climate

In this study, the indoor environmental quality (IEQ) in air conditioned residential buildings in a dry desert climate is examined from the perspective of occupants via two aspects: thermal comfort and indoor air quality. The study presents statistical data about the domestic-occupant thermal comfort sensations together with data describing the indoor air quality in Kuwaiti residential buildings. With respect to the latter, the overall IEQ acceptance using two measurements namely: physical measurements and subjective information collected via questionnaires, was used to evaluate 111 occupants living in twenty five air-conditioned residential buildings in the state of Kuwait. The operative temperature based on Actual Mean Vote (AMV) and Predicted Mean Vote (PMV) was identified using linear regression analysis of responses on the ASHRAE seven-point thermal sensation scale and was found to be 25.2°C and 23.3°C, respectively, in the summer season. Indoor air quality (IAQ) with respect to carbon dioxide concentration level was compared with the acceptable limits of international standards, i.e. ASHRAE Standard 62.1 [1]. The proposed overall IEQ acceptance findings in residential buildings show CO2 concentration level between 909 and 1250 ppm. However, this may be considered a higher level of CO2 concentration, which may require increasing ventilation rate through window operation or mechanical ventilation.

Indoor Environmental Quality in Air-conditioned Mosque Buildings in Kuwait

In this study, the indoor environmental quality (IEQ) of air-conditioned mosque buildings in an extremely dry desert climate is examined from the perspective of the occupants via two aspects: thermal comfort and indoor air quality. The study presents statistical data about the worshiper thermal comfort together with data describing the indoor air quality in Kuwaiti mosque buildings. With respect to the latter, the overall IEQ acceptance using two measurements, namely, physical measurements and subjective information collected via questionnaires, was used to evaluate 140 worshipers visiting six air-conditioned mosque buildings in the state of Kuwait. The operative temperature based on actual mean vote (AMV) and predicted mean vote (PMV) was identified using a linear regression analysis of the responses on the ASHRAE seven-point thermal sensation scale and was found to be 26.1°C in the summer season .The indoor air quality (IAQ) with respect to the carbon dioxide concentration levels was compared with the acceptable limits of international standards, i.e., the ASHRAE Standard 62.1 [1]. The proposed overall IEQ acceptance findings in the mosque buildings show CO2 concentrations between 730 and 1220 ppm. However, this is considered a slightly higher than the ideal CO2 concentrations, which may require increasing ventilation rates by opening windows and, doors or by mechanical ventilation.

Improving cooling energy efficiency in Hong Kong offices using demand-controlled ventilation (DCV) and adaptive comfort temperature (ACT) systems to provide indoor environmental quality (IEQ) acceptance

ABSTRACTSpace cooling is a significant energy consumer in office buildings in the subtropical climate zone. An adequate energy policy for indoor spaces should accordingly incorporate both energy conservation and an acceptable level of indoor environmental quality (IEQ). This study investigates the cooling energy consumption for IEQ acceptance in Hong Kong offices adopted for four space-cooling strategies: the ventilation strategies of conventional constant air volume (CAV) systems with a fixed fresh air flow rate; demand-controlled ventilation (DCV) by indoor CO2 concentration; adaptive comfort temperature (ACT) set-point adjustment; and a combination of DCV and ACT operations. Numerical equations and multiple regression formulae were used to evaluate the cooling energy consumption and IEQ acceptance in the target offices, respectively. The results show that systems equipped with DCV are more energy efficient than conventional CAV systems, while a temperature set-point adjusted between 22°C and 23°C shoul...

Indoor Environmental Quality Benchmarks for Air-conditioned Offices in the Subtropics

Indoor environmental quality (IEQ) of air-conditioned offices could be benchmarked by the occupants' acceptability. This study proposes a five-star IEQ benchmarking system based on an expression of the occupants' overall IEQ acceptance on thermal comfort, indoor air quality and aural and visual comfort. By using an earlier proposed IEQ index, the occupants' adaptive response of clothing adjustment for the perceived thermal environment was reported in order to determine the overall IEQ acceptance. The benchmarking parameter of a star rating system and the IEQ index were applied to express relative IEQ performance of air-conditioned offices in Hong Kong. The IEQ performance of some recommended environmentally sustainable policies for ``Excellent'' and ``Good'' offices was evaluated and compared with the existing offices. The probable IEQ in some Hong Kong offices were determined by Monte Carlo simulations from reports of surveyed studies. Among the existing office stock, results have shown that in offices which are renovated to the ``Excellent'' and ``Good'' IEQ criteria recommended by some policies, the IEQ acceptances for 5-star IEQ benchmarked offices are namely 0.95, 0.94, and 0.92, while for 3-star IEQ benchmarked offices, they are 0.89, 0.89, and 0.67 accordingly. The proposed star rating system would serve as a quantitative measure of IEQ for air-conditioned office environment in Hong Kong and given selected model parameters, it would be a useful reference for similar environments where the evaluation of an occupant is expected.

An evaluation model for indoor environmental quality (IEQ) acceptance in residential buildings

The indoor environmental quality (IEQ) in residential buildings is examined from the prospect of an occupant's acceptance in four aspects: thermal comfort, indoor air quality, noise level and illumination level. Based on the evaluations by 125 occupants living in 32 typical residential apartments in Hong Kong, this study proposes empirical expressions to approximate the overall IEQ acceptance with respect to four contributors, namely operative temperature, carbon dioxide concentration, equivalent noise level and illumination level, via a multivariate logistic regression model. A range of IEQ acceptances for regular residential conditions is determined and the dependence of the predicted overall IEQ acceptance on the variations of the contributors is discussed. The proposed overall IEQ acceptance can be used as a quantitative assessment criterion for similar residential environments where an occupant's evaluation is expected.

A multivariate-logistic model for acceptance of indoor environmental quality (IEQ) in offices

The indoor environmental quality (IEQ) in offices is examined from the prospect of an occupant's acceptance in four aspects: thermal comfort, indoor air quality, noise level and illumination level. Based on the evaluations made by 293 occupants of the IEQ of offices in Hong Kong, empirical expressions have been proposed to approximate an overall IEQ acceptance of an office environment at certain operative temperature ( T o), carbon dioxide concentration (CO 2), equivalent noise level ( L eq) and illumination level (lux). The overall IEQ acceptance is calculated from a multivariate logistic regression model. A range of acceptance in typical office environmental conditions and its dependence on the four parameters stated above are determined for design conditions. The proposed overall IEQ acceptance can be used as a quantitative assessment criterion for an office environment and similar environment where an occupant's evaluation is expected.