Retrofit Poverty: Socioeconomic Spatial Disparities in Retrofit Subsidies Uptake

Nicola Willand; Trivess Moore; Ralph Horne; Sarah Robertson

doi:10.5334/bc.13

Figures & Tables

Table 1

Victorian Energy Upgrade (VEU) programme categories and associated activities.

Category (abbreviation)	Activity type
Water Heating (WH)	Replacement of an electric water heating system with more efficient systems, e.g. gas/liquefied petroleum gas (LPG) storage or gas/LPG instantaneous or electric-boosted solar or gas/LPG-boosted solar systems; solar retrofit kit for existing water heating system
Space Heating & Cooling (SHC)	High-efficiency ducted gas heating system replacing an inefficient gas-ducted heating system or a central electric heater; installation of ducted air heat pump, replacement of refrigerative air-conditioner with ducted evaporative cooler; gas ductwork replacement
Space Conditioning (SC)	Ceiling and underfloor insulation; window replacements or retrofits; draught proofing
Shower Rose (SR)	Replacement with a water-efficient shower rose
Refrigerator or Freezer (Fr)	Decommissioning of an inefficient and purchase of an efficient refrigerator or freezer
Lighting Replacement (Light)	Replacement of inefficient light bulbs with more efficient ones
Television (TV)	Installation of a highly efficient television
Clothes Dryer (CD)	Installation of a highly efficient clothes dryer
Pool Pumps (PP)	Installation of a highly efficient pool pump
SPCs (SPC)	Installation of stand-by power controllers
IHDs (IHD)	Installation of in-home display units

Distribution of Victorian Energy Efficiency Certificates (VEECs) by categories of activities.

Comparison of the number of Victorian Energy Efficiency Certificates (VEECs) generated in metropolitan and regional areas.

Table 2

Descriptive statistics for Victorian Energy Efficiency Certificate (VEEC) generation: total number of VEECs.

Variable	N	Mean	SD	Minimum	Maximum
All postcode areas	689	48,503.84	70,746.93	4	555,326
Metropolitan areas	275	84,161.66	86,644.53	4	555,326
Regional areas	414	24,818.09	44,138.73	23	360,964

Comparison of Victorian Energy Efficiency Certificate (VEEC) generation intensity by categories in each location.

Table 3

Descriptive statistics for dwelling numbers and Victorian Energy Efficiency Certificate (VEEC) generation intensity.

Variable	N	Mean	SD	Minimum	Maximum
Number of occupied and unoccupied private dwellings
All postcode areas	689	3468.86	4787.51	9	34,581
Metropolitan areas	275	6265.35	5600.43	12	34,581
Regional areas	414	1611.29	2950.79	9	25,403
Total number of VEECs per 100 dwellings
All postcode areas	689	1505.92	489.59	4	3545
Metropolitan areas	275	1370.80	462.21	4	2630
Regional areas	414	1595.68	487.18	22	3545

Spatial mapping of Victorian Energy Efficiency Certificate (VEEC) generation intensity per dwelling. Also shown are the major state highways and main towns.

Spatial mapping of Victorian Energy Efficiency Certificate (VEEC) generation intensity per dwelling: all metropolitan postcode areas.

Spatial mapping of share of Victorian Energy Efficiency Certificates (VEECs) generated from the free activities of lighting upgrades, shower roses and stand-by power controllers.

Table 4

Independent samples t-test results of Victorian Energy Efficiency Certificate (VEEC) generation intensity by location.

Variable		Group statistics			t-test for equality of means			Mean difference
Variable		N	Mean	SD	t	d.f.	p	Mean difference
VEECs generation intensity
	Metropolitan areas	275	1370.80	462.21	–6.06	687	2.30E–09**	–224.89
Regional areas^a	414	1595.68	487.18
Share of VEECS from free activities (lighting upgrades, shower rose replacements, installation of stand-by power controllers)
	Metropolitan areas^a	275	0.87	0.09	31.43	681	1.10E–134**	0.25
Regional areas^a	414	0.62	0.12
VEECs generation intensity of lighting upgrade activities
	Metropolitan areas	275	748.78	330.78	9.24	409	1.42E–18**	205.64
Regional areas^a	414	543.14	201.40
VEECs generation intensity of water heating upgrade activities
	Metropolitan areas	275	89.41	115.98	–25.50	611	3.05E–98**	–374.48
Regional areas^a	414	463.90	262.78

[i] Notes: ^a Levene’s test of homogeneity of variance indicated that equal variance could not be assumed.

** Highly statistically significant at p < 0.001.

Table 5

Descriptive statistics for predictor variables with the results of an independent samples t-test to assess the difference in means between metropolitan and regional postcode areas.

		N	Mean	SD	Minimum	Maximum	t-test for equality of means			Mean difference
		N	Mean	SD	Minimum	Maximum	t	d.f.	p	Mean difference
SEIFA IER score, 2016
	All postcode areas	672	1011.23	57.09	731.00	1168.00
	Metropolitan areas	269	1023.41	70.24	731.00	1168.00	4.21	411.51	3.10E–05**	20.31^a
	Regional areas	403	1003.10	44.56	846.00	1112.00
SEIFA IRSAD score, 2016
	All postcode areas	672	1006.57	59.69	783.00	1126.00
	Metropolitan areas	269	1036.89	62.57	783.00	1126.00	11.23	471.84	4.36E–26**	50.57^a
	Regional areas	403	986.32	48.06	795.00	1097.00
Change in SEIFA IER score, 2011–16
	All postcode areas	672	2.57	14.83	–58.62	83.74
	Metropolitan areas	269	1.09	13.49	–58.62	71.62	–2.17	627.18	.030*	–2.46^a
	Regional areas	403	3.55	15.61	–39.33	83.74
Change in SEIFA IRSAD score, 2011–16
	All postcode areas	672	8.64	19.03	–62.88	110.51
	Metropolitan areas	269	3.29	18.51	–62.88	110.51	–6.12	670.00	1.57E–09*	–8.93
	Regional areas	403	12.22	18.54	–61.01	96.20
Rate of rented, occupied dwellings, 2016
	All postcode areas	689	0.22	0.13	0.00	1.00
	Metropolitan areas	275	0.27	0.16	0.03	1.00	7.83	372.21	5.14E–14**	0.08^a
	Regional areas	414	0.18	0.08	0.00	0.98
Rate of unoccupied dwellings, 2016
	All postcode areas	689	0.16	0.13	0.00	0.87
	Metropolitan areas	275	0.11	0.11	0.00	0.87	–9.92	650.33	1.10E–21**	–0.09^a
	Regional areas	414	0.20	0.13	0.00	0.78

[i] Notes: ^a Levene’s test of homogeneity of variance indicated that equal variance could not be assumed.

SEIFA IER = Socio-Economic Indexes for Areas Index of Economic Resources; and SEIFA IRSAD = Socio-Economic Indexes for Areas Index of Relative Socio-Economic Advantage and Disadvantage.

Table 6

Results of the linear regression model predicting the effect of the dependent variables on Victorian Energy Efficiency Certificate (VEEC) generation intensity, differentiated by location.

Variable		r²	ANOVA		Unstandardised coefficients			95% confidence interval for β
Variable		r²	d.f.	F	β	Constant	p	Lower bound	Upper bound
SEIFA IER score, 2016
	All postcode areas	0.069	671	49.586	2.178	–684.930	4.72E–12**	1.571	2.785
	Metropolitan areas	0.313	268	121.600	3.478	–2167.306	1.51E–23**	2.857	4.099
	Regional areas	0.010	402	3.953	1.063	534.822	0.047*	0.012	2.114
SEIFA IRSAD score, 2016
	All postcode areas	0.007	671	4.558	–0.625	2174.181	0.033	–1.252	–0.052
	Metropolitan areas	0.000	268	0.076	0.118	1270.037	0.783	–0.723	0.959
	Regional areas	0.000	402	0.002	0.023	1578.924	0.964	–0.957	1.002
Change in SEIFA IER score, 2011–16
	All postcode areas	0.003	671	2.152	1.807	1512.906	1.43E–01**	–0.612	4.225
	Metropolitan areas	0.023	268	6.224	4.888	1386.939	0.013*	1.030	8.745
	Regional areas	0.000	402	0.131	–0.555	1603.124	0.718	–3.570	2.461
Change in SEIFA IRSAD score, 2011–16
	All postcode areas	0.011	671	7.466	2.613	1494.956	0.006*	0.735	4.491
	Metropolitan areas	0.004	268	1.195	1.574	1387.099	0.275	–1.262	4.411
	Regional areas	0.003	402	1.128	1.369	1584.425	0.289	–1.165	3.904
Rate of rented, occupied dwellings, 2016
	All postcode areas	0.195	688	166.485	–1679.980	1869.770	2.91E–34**	–1935.621	–1424.340
	Metropolitan areas	0.485	274	256.862	–1971.650	1896.890	3.37E–41**	–2213.840	–1729.459
	Regional areas	0.009	413	3.919	–560.201	1698.310	0.048*	–1116.500	–3.903
Rate of unoccupied dwellings, 2016
	All postcode areas	0.056	688	40.558	–907.548	1652.686	3.49E–10**	–1187.347	–627.750
	Metropolitan areas	0.051	274	14.596	–972.691	1475.955	1.65E–04**	–1473.923	–471.459
	Regional areas	0.164	413	80.954	–1549.247	1901.376	8.55E–18**	–1887.722	1210.771

[i] Notes: VEECs were generated to 30 June 2017; SEIFA IER = Socio-Economic Indexes for Areas Index of Economic Resources; SEIFA IRSAD = Socio-Economic Indexes for Areas Index of Relative Socio-Economic Advantage and Disadvantage.

* Statistically significant at p < 0.05; ** = highly statistically significant at p < 0.001; p-values were not adjusted for multiple testing.

Table 7

Results of the linear regression model predicting the effect of the dependent variables on the Victorian Energy Efficiency Certificate (VEEC) generation intensity of lighting upgrades, differentiated by location.

Variable		r²	ANOVA		Unstandardised coefficients			95% confidence interval for β
Variable		r²	d.f.	F	β	Constant	p	Lower bound	Upper bound
SEIFA IER score, 2016
	All postcode areas	0.194	671	161.361	2.102	–1494.073	2.80E–30**	1.777	2.427
	Metropolitan areas	0.239	268	83.794	2.218	–1506.667	1.47E–17**	1.741	2.695
	Regional areas	0.076	402	32.808	1.182	–342.318	1.99E–08**	0.776	1.588
SEIFA IRSAD score, 2016
	All postcode areas	0.082	671	60.214	1.310	–687.597	3.18E–14**	0.979	1.642
	Metropolitan areas	0.006	268	1.742	0.410	338.039	0.188	–0.202	1.022
	Regional areas	0.060	402	25.708	0.978	–421.339	6.08E–07**	0.599	1.357
Change in SEIFA IER score, 2011–16
	All postcode areas	0.000	671	0.126	–0.251	632.049	0.723	–1.644	1.141
	Metropolitan areas	0.000	268	0.062	0.360	762.882	0.803	–2.488	3.208
	Regional areas	0.001	402	0.294	0.332	542.204	0.588	–0.872	1.536
Change in SEIFA IRSAD score, 2011–16
	All postcode areas	0.014	671	9.774	–1.716	646.239	0.002*	–2.794	–0.638
	Metropolitan areas	0.006	268	1.525	–1.297	767.538	0.218	–3.366	0.771
	Regional areas	0.000	402	0.071	0.138	541.701	0.790	–0.876	1.151
Rate of rented, occupied dwellings, 2016
	All postcode areas	0.045	688	32.602	–462.093	725.297	1.68E–08**	–620.991	–303.195
	Metropolitan areas	0.320	274	128.756	–1147.262	1054.905	1.05E–24**	–1346.310	–948.214
	Regional areas	0.001	413	0.591	90.314	526.596	0.442	–140.590	321.218
Rate of unoccupied dwellings, 2016
	All postcode areas	0.089	688	67.062	–653.582	730.855	1.28E–15**	–810.284	–496.880
	Metropolitan areas	0.021	274	5.899	–449.373	797.364	0.016*	–813.629	–85.118
	Regional areas	0.073	413	32.512	–426.580	627.252	2.26E–08**	–573.644	–279.516

[i] Notes: VEECs were generated until 30 June 2017 from lighting upgrade activities.

SEIFA IER = Socio-Economic Indexes for Areas Index of Economic Resources; SEIFA IRSAD = Socio-Economic Indexes for Areas Index of Relative Socio-Economic Advantage and Disadvantage.

* Statistically significant at p < 0.05; ** highly statistically significant at p < 0.001. p-values were adjusted for multiple testing.

Table 8

Results of the linear regression model predicting the effect of the dependent variables on the Victorian Energy Efficiency Certificate (VEEC) generation intensity of water heating upgrades, differentiated by location.

Variable		r²	ANOVA		Unstandardised coefficients			95% confidence interval for β
Variable		r²	d.f.	F	β	Constant	p	Lower bound	Upper bound
SEIFA IER score, 2016
	All postcode areas	0.001	671	0.406	0.122	192.870	0.524	–0.254	0.499
	Metropolitan areas	0.214	268	72.863	0.768	–694.417	1.06E–15**	0.591	945.000
	Regional areas	0.011	402	4.275	0.603	–138.440	0.039*	0.030	1.177
SEIFA IRSAD score, 2016
	All postcode areas	0.051	671	36.270	–1.076	1399.510	2.83E–09**	–1.427	–0.725
	Metropolitan areas	0.059	268	16.676	0.451	–376.590	5.90E–05**	0.234	0.669
	Regional areas	0.000	402	0.004	0.017	449.903	0.950	–0.518	0.552
Change in SEIFA IER score, 2011–16
	All postcode areas	0.008	671	5.473	1.720	312.056	0.020*	0.276	3.163
	Metropolitan areas	0.089	268	26.178	2.581	88.596	5.96E–07**	1.588	3.574
	Regional areas	0.000	402	0.064	–0.211	467.440	0.801	–1.857	1.435
Change in SEIFA IRSAD score, 2011–16
	All postcode areas	0.059	671	42.070	3.620	285.181	1.71E–10**	2.524	4.716
	Metropolitan areas	0.074	268	21.280	1.709	85.795	6.00E–06**	0.980	2.439
	Regional areas	0.009	402	3.510	1.315	450.626	0.062	–0.065	2.694
Rate of rented, occupied dwellings, 2016
	All postcode areas	0.187	688	157.863	–952.780	520.782	9.73E–33**	–1101.671	–803.890
	Metropolitan areas	0.271	274	101.705	–370.185	188.194	1.55E–20**	–442.450	–297.921
	Regional areas	0.106	413	48.852	–1013.554	649.577	1.11E–11**	–1298.611	–728.497
Rate of unoccupied dwellings, 2016
	All postcode areas	0.021	688	14.561	320.566	262.619	1.48E–04**	155.621	485.512
	Metropolitan areas	0.032	274	9.091	194.487	68.392	3.00E–03*	67.498	321.476
	Regional areas	0.034	413	14.283	–376.713	538.175	1.80E–04**	–572.651	–180.774

[i] Notes: VEECs were generated until 30 June 2017 from water heating upgrade activities.

SEIFA IER = Socio-Economic Indexes for Areas Index of Economic Resources; SEIFA IRSAD = Socio-Economic Indexes for Areas Index of Relative Socio-Economic Advantage and Disadvantage.

* Statistically significant at p < 0.05; ** highly statistically significant at p < 0.001. p-values were not adjusted for multiple testing.

Table 9

Summary of multiple regression analysis for Victorian Energy Efficiency Certificate (VEEC) generation intensity across all postcode areas.

Variable	Β	SEΒ	β	t	p
Intercept	1874.915	32.647		57.429	2.95E–264
Rate of rented, occupied dwellings, 2016	–0.09	0.03	–0.11	–3.029	0.003*
Rate of unoccupied dwellings, 2016	–1536.34	137.848	–0.404	–11.145	1.25E–26**

[i] Notes: Β = unstandardised regression coefficient; SEΒ = standard error of the coefficient; β = standardised coefficient.

* Statistically significant at p < 0.05; ** highly statistically significant at p < 0.001.

Table 10

Summary of multiple regression analysis for Victorian Energy Efficiency Certificate (VEEC) generation intensity across metropolitan postcode areas.

Variable	Β	SEΒ	β	t	p
Intercept	1912.695	39.57		48.337	1.51E–135
Rate of rented, occupied dwellings, 2016	–0.051	0.031	–0.073	–1.619	0.107
Rate of unoccupied dwellings, 2016	–1916.41	127.311	–0.677	–15.053	1.15E–37**

[i] Notes: Β = unstandardised regression coefficient; SEΒ = standard error of the coefficient; β = standardised coefficient.

** Highly statistically significant at p < 0.001.

Spatial mapping of Victorian Energy Efficiency Certificate (VEEC) generation intensity per household, excluding postcode area 3944.

Summary of the Victorian Energy Efficiency Certificate (VEEC) generation and key socioeconomic indicators for the top outlier metropolitan postcode area 3944 (Portsea).

Retrofit Poverty: Socioeconomic Spatial Disparities in Retrofit Subsidies Uptake

Figures & Tables

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