LIT_044: Howden-Chapman et al. (2021) — The Effects of Housing on Health and Well-Being in Aotearoa New Zealand

LIT_044: Howden-Chapman et al. (2021) — The Effects of Housing on Health and Well-Being in Aotearoa New Zealand

Source

https://www.healthyhousing.org.nz/resources/effects-housing-health-and-well-being-aotearoa-new-zealand-nga-panga-o-nga-whare-noho-ki — original source (opens in a new tab; the file is not redistributed)

Summary

Howden-Chapman et al. (2021) is a narrative review synthesising two decades of the He Kāinga Oranga (HKO)/Housing and Health Research Programme — six randomised community trials plus linked-administrative-data (IDI) programme evaluations — measuring the health, well-being and economic effects of NZ housing quality. The paper documents the strong association between housing quality and tenure (rental stock is older, colder, damper, mouldier), the disproportionate exposure of Māori, Pacific, disabled and low-income people, and quantifies the public-sector cost of substandard housing. It frames the NZ evidence as the base that underpinned the 2018 WHO Housing and Health Guidelines and the subsequent regulatory response (Healthy Homes Standards 2019, Warmer Kiwi Homes, Healthy Homes Initiative). For Neobiome Intelligence the value is a national NZ baseline on indoor temperature, damp/mould prevalence, energy poverty, retrofit benefit-cost ratios, and the monetised burden of inadequate housing — directly relevant to basic-needs (I07), building/habitat (D04) and resilience (I06) reasoning.

Key claims

- claim: "In the 2018 Census, 34% of people reported homes sometimes/always damp and 36% reported homes mouldy; the average winter daytime indoor temperature is 19°C, with 33% of homes below 18°C."
  source_location: "p.18, para 1 (citing Stats NZ 2018; Stats NZ 2020)"
- claim: "More than one-quarter of NZ households experience energy poverty, defined as paying more than 10% of income on household (non-travel) energy costs."
  source_location: "p.18, para 1 (citing Howden-Chapman et al., 2012)"
- claim: "EECA-funded retrofitted insulation has been installed and audited into over 300,000 homes through Warmer Kiwi Homes and predecessor programmes."
  source_location: "p.19, para 1"
- claim: "Retrofitting insulation in existing NZ housing has a benefit-to-cost ratio of 4.7:1 when hospitalisation and mortality are both considered (Warmer Kiwi Homes whole-population evaluation); the earlier Housing Insulation and Health Study trial found a ratio close to 2:1."
  source_location: "p.23 para 2 (Grimes & Preval 2020, BCR 4.7:1); p.20 para 1 (Chapman et al. 2009, BCR ~2:1)"
- claim: "Direct public-sector costs attributable to unsafe and substandard housing are approximately NZ$141 million per year (range $127–160m), including ~6300 hospitalisations from damp/mould (~37,000 hospital nights, ~$36m), 1500 from injuries, 625 from cold housing and 500 from crowding; ~230 deaths are attributable, monetised at approximately NZ$1 billion/year (June 2017 NZD)."
  source_location: "p.24, paras 1 (Riggs et al. 2021)"
- claim: "Each year ~28,000 children and ~54,000 adults are admitted to hospital for potentially avoidable hospitalisations linked to poor housing; the Healthy Homes Initiative prevented ~1533 hospitalisations, 9443 GP visits and 8784 filled prescriptions in its first year (~$10.4m saved), with ~$30m in averted costs expected over 3 years."
  source_location: "p.22 para 4 (Oliver et al. 2018) and p.23 para 1 (Pierse et al. 2019)"
- claim: "Home-modification injury-prevention interventions (HIPI) cut home fall injuries by 26% and home-modification-specific injuries by 39% (33% reduction in ACC fall-injury costs); the Māori HIPI (MHIPI) cut home-modification-specific injuries by 45% per year — health benefits are larger for Māori even under identical interventions."
  source_location: "p.21, para 1 (Keall et al. 2017; Keall et al. 2021)"
- claim: "The public housing waiting list had risen to over 23,680 applicants amid COVID-19 era rent and unemployment pressure, despite the Kāinga Ora public-housing programme."
  source_location: "p.26, para 2 (Howden-Chapman 2020)"

Neobiome Intelligence relevance

• NZ indoor-comfort baseline (I07, D04): national damp (34%), mould (36%), sub-18°C (33%) and 19°C mean winter daytime indoor temperature figures give a habitat-performance baseline for what a self-sufficient community build must exceed. LIT_044
• Energy-poverty threshold (I07, I01): the >10%-of-income energy-cost definition and the >25% of households above it anchor the energy-affordability target in NI’s basic-needs reasoning. LIT_044
• Retrofit benefit-cost evidence (I01, D04): the 4.7:1 (whole-population) and ~2:1 (trial) insulation BCRs are reusable NZ benchmarks for the economic case for high-performance habitat in community costings. LIT_044
• Resilience and equity (I06, I10): documents that identical interventions yield larger benefits for Māori (MHIPI 45% injury cut) and that disaster/tenure insecurity (Canterbury earthquakes “Inverse Care Law”, residential mobility) degrade well-being — supports equity-weighted and shock-resistance reasoning. LIT_044

Research targets

Documents to retrieve

• Riggs, L. et al. (2021) — Environmental burden of disease from unsafe and substandard housing, New Zealand, 2010–2017 — primary source behind the 141m / 230-deaths / 1bn burden figures cited on p.24; already in inbox as rt056 (proposed sibling ingest LIT_045). Retrieve to verify the cost decomposition rather than relying on the review’s summary.
• Pierse, N., White, M. & Riggs, L. (2019) — Healthy Homes Initiative Outcomes Evaluation Service: Initial analysis of health outcomes (Interim Report, He Kāinga Oranga/Motu) — primary source behind the 1533 hospitalisations / 10.4m / 30m figures on p.23. RESOLVED → OT_152 (RT_208). All three headline figures confirmed against the primary (1,533 prevented hospitalisations; 10,402,150 Year-1 and 29,473,374 three-year costs averted; ROI in Year 2). ⚠ The per-region breakdown that motivated retrieval does not exist in this interim report — the analysis is aggregate across the 1,608-referral sample; a per-region/all-household IDI breakdown is deferred to the (as-yet-unpublished) Phase-2 evaluation.
• Grimes, A. & Preval, N. (2020) — Warmer Kiwi Homes Evaluation 2020: Phase 1 (Report to EECA), Motu — primary source for the 4.7:1 insulation benefit-cost ratio. RESOLVED → OT_087. The primary BCR is 4.66:1 (Table 5; the 4.7 here is rounded), robust across scenarios 1.83–5.25, and ~82% an insulation→elderly-mortality benefit (not an energy-savings figure).

Research gaps

• National, current (post-2018) NZ household indoor-temperature and damp/mould prevalence dataset at regional resolution — the figures here derive from the 2018 Census and the 2018–2020 General Social Survey; NI needs an all-NZ, regionally disaggregated habitat-comfort baseline rather than national aggregates.
• NZ-specific monetised benefit-cost ratios for combined retrofit packages (insulation + heating + ventilation) at community/cluster scale, as opposed to single-measure insulation retrofits evaluated here.

Connections

Links to

Sources (2): OT_087 · OT_152

Referenced by

Sources (5): LIT_045 · OT_042 · OT_087 · OT_152 · OT_156

SSI indicators (4): I01: Financial & Economic Self-Sufficiency · I06: Resistance to External Shocks · I07: Fulfilment of Basic Needs · I10: Psychological Self-Sufficiency

EDT domains (1): D04: Sustainable Habitat & Building Technology

Concepts (1): Healthy Housing — Warmth, Dryness & Wellbeing