Methodology

Sources, definitions and refresh notes.

Primary source

Regional observations come from the Electricity Authority’s EMI RegionalPowerPrices dataset. The current committed file is 20260531_AveragePowerUseAndCosts.csv, checked 21 September 2026 and covering January 2025 to May 2026.

The file contains one row per month, network-reporting region and user profile. “Low user” and “standard user” are the source’s profiles, not Younivi-created household archetypes. The total monthly bill is the source’s published indicative total including GST; the variable rate and network monthly charge are displayed as supporting fields.

Licensing and attribution

The Electricity Authority states that EMI copyright material is generally available for reuse under the Creative Commons Attribution 4.0 International licence, subject to exclusions in its legal information. Attribution used here is: “Electricity Authority, www.emi.ea.govt.nz provided by the Electricity Authority (New Zealand)”. Younivi does not reuse EMI logos, design elements or restricted material.

Refresh procedure

From the repository root, run:

python scripts/fetch_data.py
python scripts/build.py

The fetch script discovers the current CSV link from the dataset page, downloads it, validates the schema, rejects duplicate month/region/profile keys and regenerates regional-power-prices.json. If the normalized source hash is unchanged it exits without rewriting files. Revised historical data is accepted only when the schema and numeric fields still validate; the new hash and date range are recorded in the JSON metadata.

Commit the generated data and static output to main. Cloudflare Pages serves the repository root as a static site. The source page is currently updated on a release cadence rather than continuously; a daily check is safe because unchanged releases produce no file changes.

Calculator

The running-cost estimate is: watts ÷ 1000 × hours per day × tariff dollars per kWh. Weekly cost multiplies by days used per week; monthly cost is annual cost divided by 12 and annual cost uses 52 weeks. It excludes fixed daily charges, plan-specific discounts, time-of-use periods and appliance cycling unless the visitor’s entered tariff and usage already account for them.