Figure 1
Historical overview of the evolution of priorities within the green building industry.
Figure 2
Qualitative illustration of the body of the existing peer-reviewed evidence on green-certified buildings.
Source: Research evidence summarised in the review by Allen et al. (2015).
Table 1
Challenges of the research approaches.
| EXAMPLE OF RESEARCH DESIGN LIMITATIONS | SELECTED REFERENCES |
|---|---|
| Inconsistency between post-occupancy research hypotheses and design intents (e.g. evaluation for human-centric lighting versus design for work plane illumination) | Leder et al. (2016), Altomonte et al. (2019), Pastore & Andersen (2019) |
| Inconsistent and non-standardised occupant surveys | Meir et al. (2009), Duarte Roa et al. (2020) |
| Reliance on indirect and subjective metrics | Ucci & Godefroy (2020) |
| Little or no control of confounding variables, such as socio-economic, demographic or health factors | Evans & Kantrowitz (2002), Brown et al. (2015) |
| Limited or constrained efforts to establish rigorous peer or control groups for comparative studies or objective matching between green-certified and non-certified buildings | Newsham et al. (2013), Mac Naughton et al. (2017), Lee et al. (2019, 2020) |
| Limited consideration for sample size or statistical power | Brown & Cole (2009), Thatcher & Milner (2012), Agha-Hossein et al. (2013) |
Table 2
Selected efforts supporting the development of new methods for indoor environmental quality (IEQ) assessment.
| EXAMPLES OF PROPOSED METHODS FOR IEQ ASSESSMENT | SELECTED REFERENCES |
|---|---|
| Rating of satisfaction with individual IEQ components with respect to the overall satisfaction with the indoor environment | Clausen et al. (1993), Alm et al. (1999), Jin et al. (2012) |
| IEQ index based on the functions describing the percentage of dissatisfied people across multiple IEQ parameters | Piasecki et al. (2017) |
| IEQ index based on five factors, including air temperature, relative humidity, CO2 concentration, horizontal illuminance and sound pressure level | Wong et al. (2018), Huang et al. (2012) |
| IEQ evaluation method based on the parameters prescribed by EN 16798-1 (2020) | Danza et al. (2020) |
| IEQ asset rating method for residential buildings linking design expectations with occupant evaluations | Larsen et al. (2020) |
| Method that combines measurements of energy performance, IEQ and wellbeing indicators | Magyar et al. (2021) |
| IEQ index based on combined IEQ measurements determined with reference to EN 16798-1 (2020) and WHO (2006) air quality guidelines | Wargocki et al. (2021), Mujan et al. (2021) |
Figure 3
Potential reasons contributing to a predominant focus on energy-related issues in green rating schemes as opposed to indoor environmental quality (IEQ).
Sources: Authors’ experience and, in part, through interpretation of the existing literature (e.g. Hamilton et al. 2016).
Table 3
Summary of current research and key proposed recommendations for researchers.
| CURRENT STATE | PROPOSED RESEARCH RECOMMENDATIONS |
|---|---|
| Inconsistency in methods leading to difficulties in robust benchmarking (see Section 3.1) |
|
| Lack of reporting of independent variables (see Section 3.1) |
|
| Lack of a clear consolidated framework for IEQ performance measurements (see Section 3.2) |
|
| Limited capacity of current modelling approaches to reliably predict IEQ and occupant outcomes in buildings (see Section 3.2) |
|
| Investigation of human responses to IEQ that are currently over-regulated within narrow and static ranges (targeting neutrality and average acceptability) (see Section 3.3) |
|
| Investigation of monotonic human responses to environmental stimuli (see Section 3.3) |
|
| Lack of collaboration across disciplines |
|
Table 4
Current state of green rating systems and key recommendations.
| CURRENT STATE | PROPOSED RECOMMENDATIONS |
|---|---|
| Relative priority on environmental/energy performance over health and experience. Variable adoption of indoor environmental quality (IEQ)-related credits (see Section 4.1) |
|
| Lack of customisation in IEQ scoring at a global scale (see Section 4.1) |
|
| Pursuing IEQ credits that are not of primary concern for a specific building context (see Section 4.2) |
|
| Focus on conventional categories of IEQ and exclusion of many health-relevant metrics (see Section 4.2) |
|
| Insufficient transparency in requirements and measured outcomes. Practice of ‘greenwashing’ (see Section 4.2) |
|
| Heavy reliance on base requirements from conventional IEQ standards (see Section 4.3) |
|
| Loose and sporadic requirements for occasional IEQ performance verification (see Section 4.5) |
|
| Absence of requirements for continuous monitoring that make IEQ performance based on design and not actual conditions (see Section 4.5) |
|
| Underdeveloped methods for sampling, data analysis, scoring, interpretation and communication (see Section 4.5) |
|
| Loose and insufficient requirements to acquiring professional accreditation (see Section 4.6) |
|
| Lack of flexibility to encompass future occupant needs and adverse events |
|
Figure 4
Four-tier building performance model with progression from sick buildings (Tier 1) to envisioned future green buildings (Tier 4).