An exploration of experts’ views on the relative importance of indoor-environmental quality parameters

Figures & data

Table 1. Example of cited (IEQ-related) national and international sets of weights related to thermal comfort (TC), air quality (AQ), acoustic comfort (AC) and visual comfort (VC) (cited from Fathi & O’Brien, 2023; Wei et al., 2020).

	TC	AQ	AC	VC
USA	0.12	0.20	0.39	0.29
Taiwan	0.24	0.34	0.23	0.19
China	0.38	0.14	0.27	0.21
DGNB	0.25	0.25	0.25	0.25
BREEM	0.17	0.28	0.22	0.33
NABERS	0.33	0.33	0.17	0.17

Table 2. Overview of the share of the IEQ-related evaluation domains (in percentage) of the total score in the DGNB system (new buildings) as a function of building type (based on Mahdavi et al., 2020).

IEQ domain	Building type
	Office	Educational	Hotel	Residential	Consumer market	Shopping centre	Department stores	Logistics	Production
Thermal comfort	4.1	3.6	3.9	4.3	4.5	4.5	4.5	4.3	4.3
Indoor air quality	5.1	4.5	4.9	5.4	4.5	4.5	4.5	5.4	5.4
Acoustic comfort	2.0	2.7	2.9	0.0	0.0	0.0	0.0	0.0	0.0
Visual comfort	3.1	2.7	2.0	3.2	3.4	3.4	3.4	3.2	3.2
User control	2.0	1.8	2.0	2.1	2.3	2.3	2.3	0.0	0.0
Total for IEQ	16.3	15.3	15.7	15	14.7	14.7	14.7	12.9	12.9

Table 3. Comparison between weighting factors derived from field studies related to thermal comfort (TC), air quality (AQ), acoustic comfort (AC) and visual comfort (VC) (based on Danza et al., 2020).

Weights	TC	AQ	AC	VC
USA	0.12	0.20	0.39	0.29
Italy	0.29	0.23	0.25	0.23
Taiwan	0.24	0.34	0.23	0.19
UK	0.30	0.36	0.18	0.16
China	0.38	0.14	0.27	0.21
China	0.31	0.25	0.24	0.20
Australia	0.33	0.33	0.17	0.17
Nigeria	0.31	0.23	0.26	0.20

Table 4. Overview of the five domains subjected to expert ranking, as well as ranking items within each domain.

IEQ domains	Ranked items	Code
Thermal quality (TQ)	Maintaining the preferred air temperature	TQ_AT
	Avoidance of very high/low relative humidity	TQ_RH
	Avoiding draft (winter)	TQ_DW
	Avoidance of radiant asymmetry	TQ_RA
	Avoiding draft (summer)	TQ_DS
Indoor air quality (IQ)	Absence of unpleasant odours	IQ_UO
	Air freshness	IQ_AF
	Presence of operable windows	IQ_OW
	Presence of pleasant odours	IQ_PO
	Perception of air dryness	IQ_AD
Visual quality (VQ)	Availability of daylight	VQ_DL
	Avoidance of glare in the field of view	VQ_GL
	View to outside	VQ_VO
	Maintaining the preferred Illuminance levels	VQ_IL
	Colour temperature of light sources	VQ_CT
Acoustic quality (AQ)	Avoidance of speech noise from adjacent workstations	AQ_SN
	Avoidance of noise from inside (equipment, HVAC, etc.)	AQ_NI
	Maintaining acoustic privacy	AQ_AP
	Avoidance of outside noise (e.g. traffic)	AQ_ON
	Avoidance of hall/echoes	AQ_HE
Infrastructure/amenities (IN)	Personal control over environmental systems (HVAC)	IN_PC
	Connectivity (wireless availability and speed)	IN_WA
	Individual offices (versus shared offices)	IN_IO
	Ergonomic furniture	IN_EF
	High-quality equipment (computers, printers, etc.)	IN_EQ

Figure 1. Participants’ ranking of the five IEQ domains.

Figure 2. Participants’ ranking of the IEQ domains and their sub-categories (‘high’ denotes the percentage of votes ranking an item as either rank 1 or rank 2, whereas ‘low’ denotes the percentage of votes ranking an item as either rank 4 or rank 5).

Table 5. Summary of participants’ ranking of IEQ domains as well as sub-categories in each domain subjected to expert ranking in terms of mean and standard deviation (Sd).

IEQ domains	Ranked items	Code	Mean	Sd
Indoor-environmental quality (IEQ)	Thermal quality	TQ	1.93	1.13
	Indoor air quality	IQ	2.77	1.46
	Visual quality	VQ	3.29	1.20
	Acoustic quality	AQ	3.32	1.22
	Infrastructure/amenities	IN	3.70	1.38
Thermal quality (TQ)	Air temperature	TQ_AT	1.73	1.03
	Relative humidity	TQ_RH	2.96	1.45
	Draft (winter)	TQ_DW	2.85	1.13
	Radiant asymmetry	TQ_RA	3.23	1.20
	Draft (summer)	TQ_DS	4.23	1.01
Indoor air quality (IQ)	Unpleasant odours	IQ_UO	2.07	1.19
	Air freshness	IQ_AF	2.07	1.00
	Operable windows	IQ_OW	2.84	1.33
	Pleasant odours	IQ_PO	4.23	0.99
	Air dryness	IQ_AD	3.79	0.99
Visual quality (VQ)	Daylight	VQ_DL	2.36	1.32
	Glare	VQ_GL	2.37	1.24
	View	VQ_VO	3.19	1.27
	Illuminance	VQ_IL	3.03	1.34
	Colour temperature	VQ_CT	4.05	1.21
Acoustic quality (AQ)	Speech noise	AQ_SN	2.49	1.14
	Noise from inside	AQ_NI	2.60	1.32
	Acoustic privacy	AQ_AP	3.21	1.53
	Outside noise	AQ_ON	2.56	1.31
	Hall/echoes	AQ_HE	4.14	1.03
Infrastructure/amenities (IN)	Personal control	IN_PC	2.74	1.35
	Connectivity	IN_WA	2.70	1.34
	Individual offices	IN_IO	3.40	1.61
	Ergonomic furniture	IN_EF	3.03	1.43
	Equipment	IN_EQ	3.14	1.23

Table 6. Participants’ ranking (mean score) of the IEQ domains (and their sub-categories) broken down for various subsets of the participants, i.e. gender (female/male), profession (architect, engineer, educator/researcher), area of expertise (TQ, IQ, VQ) and location (Europe, Americas, Asia).

IEQ domain	Ranked items	Gender		Profession			Expertise			Location
		F	M	Arch.	Eng.	Ed/Re	TQ	IQ	VQ	Europe	Americas	Asia
IEQ	TQ	2.00	1.76	2.25	1.72	2.00	1.83	2.00	2.75	2.00	2.24	1.29
	IQ	3.07	2.62	2.83	2.44	2.93	2.76	2.71	4.25	2.72	3.18	2.53
	VQ	3.26	3.38	3.17	3.52	3.22	3.44	3.57	1.50	3.13	3.29	3.41
	AQ	3.07	3.43	3.33	3.20	3.48	3.20	3.00	3.50	3.00	3.18	3.88
	IN	3.59	3.81	3.42	4.12	3.37	3.76	3.71	3.00	4.16	3.12	3.88
TQ	TQ_AT	1.70	1.79	1.67	1.88	1.67	1.72	2.00	1.75	1.63	1.88	1.94
	TQ_RH	3.07	2.76	2.92	3.16	2.56	2.96	2.00	3.75	3.38	3.06	1.82
	TQ_DW	2.74	3.00	2.67	2.60	3.22	2.93	2.71	2.75	2.53	3.00	3.47
	TQ_RA	3.15	3.19	3.67	3.16	2.96	3.17	3.86	2.25	2.91	2.94	3.94
	TQ_DS	4.33	4.26	4.08	4.20	4.59	4.22	4.43	4.50	4.56	4.12	3.82
IQ	IQ_UO	2.15	1.98	3.17	1.80	1.85	1.89	2.43	2.75	1.78	2.00	2.71
	IQ_AF	2.11	2.00	1.67	2.28	2.00	2.09	2.29	1.75	2.19	1.94	1.88
	IQ_OW	2.44	3.05	2.75	2.64	3.00	2.78	1.57	3.75	2.75	2.59	3.18
	IQ_PO	4.30	4.19	4.08	4.40	4.19	4.26	4.86	3.25	4.38	4.76	3.41
	IQ_AD	4.00	3.79	3.33	3.88	3.96	3.98	3.86	3.50	3.91	3.71	3.82
VQ	VQ_DL	2.59	2.24	2.25	2.40	2.30	2.37	2.43	2.50	2.31	2.06	2.76
	VQ_GL	2.07	2.52	2.92	2.28	2.30	2.39	2.57	1.75	2.22	2.35	2.71
	VQ_VO	3.41	3.05	2.83	3.04	3.37	3.13	3.00	3.25	2.88	3.29	3.47
	VQ_IL	2.81	3.10	3.00	3.04	2.85	3.07	2.71	3.50	3.25	3.29	2.47
	VQ_CT	4.11	4.10	4.00	4.24	4.19	4.04	4.29	4.00	4.34	4.00	3.59
AQ	AQ_SN	2.22	2.74	2.42	2.76	2.26	2.48	2.57	2.25	2.41	2.35	2.88
	AQ_NI	2.59	2.64	3.00	2.48	2.70	2.52	2.86	1.75	2.41	3.00	2.71
	AQ_AP	3.44	3.05	3.08	3.32	3.26	3.22	2.86	4.50	3.41	2.88	3.18
	AQ_ON	2.81	2.33	2.50	2.44	2.52	2.63	2.43	2.00	2.72	2.41	2.06
	AQ_HE	3.93	4.24	4.00	4.00	4.26	4.15	4.29	4.50	4.06	4.35	4.18
IN	IN_PC	2.44	2.86	2.50	2.72	2.74	2.76	2.29	2.50	2.88	2.35	2.53
	IN_WA	2.19	3.02	2.33	2.88	2.74	2.70	2.57	2.75	2.69	2.82	2.82
	IN_IO	3.70	3.26	4.00	3.32	3.30	3.56	3.29	2.00	3.47	3.35	3.29
	IN_EF	3.22	3.00	3.25	3.16	2.93	3.00	3.29	3.50	2.78	3.06	3.59
	IN_EQ	3.44	2.86	2.92	2.92	3.30	2.98	3.57	4.25	3.19	3.41	2.76

Table 7. Order of participants’ importance ranking of IEQ main domains and sub-categories based on: (i) destination as highest ranking, (ii) inclusion in highest and second highest ranking and (iii) mean ranking score.

IEQ domains	IEQ domain sub-categories	Ranked as highest	Included in the top 2	Rank due to mean score	Resultant ranking
IEQ	TQ	1	1	1	1
	IQ	2	2	2	2
	VQ	3	4	3	3
	AQ	5	3	4	4
	IN	4	5	5	5
Thermal quality (TQ)	TQ_AT	1	1	1	1
	TQ_DW	3	2	2	2
	TQ_RH	2	3	3	3
	TQ_RA	4	4	4	4
	TQ_DS	5	5	5	5
Indoor air quality (IQ)	IQ_AF	2	1	1	1
	IQ_UO	1	2	2	2
	IQ_OW	3	3	3	3
	IQ_AD	5	4	4	4
	IQ_PO	4	5	5	5
Visual quality (VQ)	VQ_DL	1	1	1	1
	VQ_GL	2	2	2	2
	VQ_IL	3	3	3	3
	VQ_VO	4	4	4	4
	VQ_CT	5	5	5	5
Acoustic quality (AQ)	AQ_SN	4	1	1	1
	AQ_ON	1	2	2	2
	AQ_NI	3	3	3	3
	AQ_AP	2	4	4	4
	AQ_HE	5	5	5	5
Infrast./amenities (IN)	IN_PC	1	1	2	1
	IN_WA	3	2	1	2
	IN_EF	4	3	3	3
	IN_EQ	5	4	4	4
	IN_IO	2	5	5	5

Figure 3. Comparison of the percentage of participants who evaluated different IEQ domains as high (sum of rankings 1 and 2) by participants with different main area of expertise (i.e. thermal quality, visual quality, indoor air quality).

Figure 4. Comparison of the percentage of participants who evaluated different IEQ domains as high (sum of rankings 1 and 2) shown separately for female and male participants.

Figure 5. Comparison of the percentage of participants who evaluated different IEQ domains as high (sum of rankings 1 and 2) by participants with different professional background (i.e. architects, educators/researchers, engineers).

Figure 6. Comparison of the percentage of participants who evaluated different IEQ domains as high (sum of rankings 1 and 2) by participants from different locations (Europe, Americas, Asia).

Figure 7. The assignment of weights (y-axis) based on participants’ mean ranking tendency (x-axis).

Table 8. Weights derived for the five IEQ domains and the respective sub-categories in each domain based on participants’ corresponding mean ranking votes (the numeric values of the weights in each category are derived in a manner so as to add to one).

Indoor-environmental quality domains
Thermal quality	Indoor air quality	Visual quality	Acoustic quality	Infrastructure/amenities
0.27	0.22	0.18	0.18	0.15
Thermal quality
Air temperature	Relative humidity	Draft (winter)	Radiant asymmetry	Draft (summer)
0.28	0.21	0.21	0.18	0.12
Indoor air quality
Air freshness	Unpleasant odours	Operable windows	Air dryness	Pleasant odours
0.26	0.26	0.21	0.15	0.12
Visual quality
Daylight	Glare	Illuminance	View	Colour temperature
0.24	0.24	0.20	0.19	0.13
Acoustic quality
Speech noise	Noise from inside	Outside noise	Acoustic privacy	Hall/echoes
0.23	0.23	0.23	0.19	0.12
Infrastructure/amenities
Personal control	Connectivity	Ergonomic furniture	Equipment	Individual offices
0.22	0.22	0.20	0.19	0.17

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