Source
https://www.branz.co.nz/pubs/research-reports/sr221/ — original source (opens in a new tab; the file is not redistributed)
Data vintage — validate before use (20+ years old)
HEEP field monitoring ran 1999–2005. Every absolute figure below reflects the 2005 NZ housing stock and appliance fleet. Since then heat pumps have largely displaced resistance heating, LEDs have cut lighting energy, and appliance efficiency has risen — so the end-use shares and absolute kWh have shifted. Treat HEEP as the authoritative structure of NZ household energy demand; cross-check current magnitudes against EECA EEUD, EECA Electric Homes (2024), and HEEP2 (RT_098). The model’s space-heat synthesis (CR_015) already discounts HEEP by ~0.843 for this reason. Update (2026-06): HEEP2’s first report is now ingested as OT_042 — it confirms living areas have warmed (~20°C evening, the heat-pump era assumed by CR_015’s 0.843 factor) while bedrooms remain cold; but it is the winter-comfort/temperature report only, so HEEP2’s energy end-use split is still pending and OT_037 remains the demand-split primary until it is published.
Summary
BRANZ Study Report SR221 (Isaacs et al., 2010) is the final report of the Household Energy End-use Project (HEEP) — the largest and most detailed measurement of how New Zealand homes actually use energy. Around 400 houses were randomly sampled nationally and physically monitored (energy by fuel and end-use, indoor temperatures, appliance inventories) over the period 1999–2005. It established the canonical NZ household-energy figures: an average of 11,410 kWh/dwelling/year across all fuels, split 34% space heating, 29% hot water, ~37% appliances/lighting/cooking, with electricity supplying 69% of the energy and NZ homes running cold (mean winter evening living-room temperature 17.9°C, below the WHO 18°C minimum). For Neobiome Intelligence it is the primary source behind the demand-split the model already carries through the compiled syntheses CR_009 and CR_015 — but its 2005 vintage means it anchors structure, not current magnitudes.
Key claims
- claim: "HEEP is the largest NZ household-energy end-use study: a national random sample of ~400 houses physically monitored (energy by fuel + end-use, indoor temperatures, appliance inventory) with data collection completed in 2005; final report published 2010 (BRANZ SR221, Isaacs et al.). [DATA VINTAGE: 2005 — ~20 years old.]"
source_location: "Abstract; §1 (p.7); front matter"
- claim: "National average total household energy consumption (all fuels) = 11,410 kWh/occupied dwelling/year (SE 420). Regional averages: Auckland 10,660, Hamilton/Tauranga 10,750, Wellington 10,860, Christchurch 11,010, Dunedin/Invercargill 14,580; warm clusters 9,960, cool clusters 13,780. [2005 vintage — validate.]"
source_location: "Table 4 (p.13)"
- claim: "Average energy per occupant = 3,930 kWh/occupant/year nationally (mean 2.90 occupants/dwelling), rising in colder climates (Dunedin/Invercargill 5,500 kWh/occupant/yr). [2005 vintage — validate.]"
source_location: "Table 5 (p.13)"
- claim: "Household energy by end-use (Figure 14): space heating 34%, hot water 29%, other appliances 13%, refrigeration 10%, lighting 8%, range/cooking 6%. Space heating rises to ~70% of energy use in the coldest climates. [2005 vintage — validate; heat-pump/LED uptake has since shifted these shares.]"
source_location: "Figure 14 (p.15) and summary text"
- claim: "Combined water + space heating means just under two-thirds (63%) of household energy is for low-grade heat (<100°C) — the structural target for heat-side self-sufficiency. [2005 vintage — directionally durable.]"
source_location: "§ summary (Figure 14 discussion, p.15)"
- claim: "Household energy by fuel (Figure 13): electricity 69%, solid fuel 20%, reticulated gas 9%, bottled LPG 2%, oil ~0%. Average annual household electricity consumption = 7,800 ±420 kWh/year. [2005 vintage — validate; solid-fuel share has since fallen.]"
source_location: "Figure 13 (p.15); §2 (p.13)"
- claim: "Consumption is highly skewed: the top 20% of households each use more than 14,450 kWh/year and together account for 36% of all residential energy; the bottom 20% each use less than 6,940 kWh/year. A single mean conceals a 4,000–14,000+ kWh/yr spread. [2005 vintage.]"
source_location: "Figure 7 (p.11); Table 2 (p.11)"
- claim: "NZ homes run cold: the mean and median national winter-evening living-room temperature is 17.9°C — below the WHO-recommended 18°C minimum — reflecting NZ's partial/spot-heating culture and low insulation/heating provision. [2005 vintage; pre-Healthy-Homes-Standards.]"
source_location: "Figure 37 (winter evening living-room temperature distribution)"Neobiome Intelligence relevance
- D01 — ② regional energy-demand split (the primary behind CR_009 / CR_015). HEEP is the original source of the 34% space / 29% water / 37% appliances-lighting-cooking split the model uses, and of the 11,410 kWh/dwelling and 7,800 kWh electricity baselines OT_037. Ingesting it moves these from synthesis-cited (CR_009) to primary-sourced — but the 2005 vintage means the model must validate magnitudes against current data (EECA EEUD / Electric Homes / HEEP2) before use; the share structure is more durable than the absolute kWh.
- D04 — building-fabric performance case. The 17.9°C mean winter living-room temperature (below WHO 18°C) and the finding that 63% of household energy is low-grade heat are the quantitative basis for prioritising thermal-envelope performance in a community build — directly complementing the LIT_044 housing-health baseline OT_037. Validate: this is the pre-2008 stock, before insulation retrofits and the Healthy Homes Standards 2019.
- I07 — basic-needs energy provisioning. A NZ household energy-provision baseline (11,410 kWh/dwelling/yr; 3,930 kWh/occupant/yr; heat dominating at 63%) for sizing community self-sufficiency OT_037. Validate before applying — 2005 magnitudes.
Research targets
Documents to retrieve
- HEEP2 (BRANZ, fieldwork 2018–) — the direct successor (750+ households); when published it supersedes HEEP1 as the canonical NZ household-energy evidence base. Tracked as RT_098 — the priority refresh for every figure on this page.
- EECA Energy End-Use Database (EEUD) and EECA Electric Homes (2024) — already partly in the wiki; the modern cross-checks for the HEEP splits.
Research gaps
- A current (post-2018) NZ household end-use split to quantify how far heat-pump and LED uptake have shifted HEEP’s 34/29/37 structure — needed before the model relies on HEEP magnitudes rather than its structure.
- HEEP’s regional totals predate widespread heat pumps; a modern regional space-heat series (partly addressed by CR_015’s 0.843 modernisation factor) would replace the interpolation.
Connections
Links to
Referenced by
Sources (9): CR_009 · CR_015 · CR_051 · OT_042 · OT_072 · OT_106 · OT_123 · OT_159 · RD_020
EDT domains (2): D01: Renewable Energy & Storage Systems · D04: Sustainable Habitat & Building Technology
SSI indicators (1): I07: Fulfilment of Basic Needs
Concepts (1): Healthy Housing — Warmth, Dryness & Wellbeing