Reference question
How much electricity might a covered 100-gallon outdoor cold plunge require to hold 50°F across different U.S. climates and electricity rates? Every indexed city uses the same three setup scenarios so comparisons remain consistent.
Three setup scenarios
| Scenario | UA | Baseline | Reference COP | Daily load allowance |
|---|---|---|---|---|
| Efficient insulated | 10 BTU/hr/°F | 1.0 kWh/day | 2.6 | 0.15 kWh/day |
| Reference consumer | 18 BTU/hr/°F | 1.6 kWh/day | 2.2 | 0.55 kWh/day |
| Lightly insulated / exposed | 32 BTU/hr/°F | 2.4 kWh/day | 1.8 | 1.0 kWh/day |
UA is effective thermal conductance. Baseline covers continuous circulation, filtration and sanitation loads. The daily allowance represents omitted loads such as solar gain, open-cover use, pump heat and water changes. Those allowances are explicit assumptions pending field calibration.
Climate calculation
The updater requests NOAA/NCEI 1991–2020 monthly normal mean, minimum and maximum temperatures from a nearby station. For each month, ArcticSoak approximates a 24-hour sinusoidal temperature curve and sums only the hourly temperature difference above the water target. This avoids treating a 40°F night as if it cancels a 90°F afternoon.
If a complete NOAA record cannot be retrieved, the build retains the last verified record. If none exists, it publishes a provisional seed profile. Every provisional city is labeled in HTML, CSV and JSON. ArcticSoak does not describe those rows as NOAA-derived.
Energy calculation
The model reduces COP as the monthly normal high rises above 75°F, with a floor of 1.2. This is a generic sensitivity adjustment rather than a specific chiller performance curve.
Electricity prices
When an EIA API key is configured, the updater requests the latest monthly state residential average retail price from the U.S. Energy Information Administration. That number is an average revenue per kilowatt-hour, not a utility-specific tariff. When an EIA update is unavailable, the page retains or uses a disclosed bundled planning value. City pages display the source and period.
Primary sources: NOAA U.S. Climate Normals · EIA retail electricity data
ArcticSoak Score
The 0–100 score is a comparative summary: 75% modeled cooling-degree-hour burden and 25% reference-scenario annual cost. It is not a physical unit. ArcticSoak presents kWh, dollars and scenario range first; the score is secondary.
Known limitations
- Solar radiation, humidity, wind, plumbing length, tub color and cover habits are not modeled from city-specific measurements.
- Generic COP sensitivity cannot replace a chiller's tested performance curve.
- Electricity data is state-level; bills can include tiering, fixed charges and local rates.
- Monthly normals describe climate, not a particular year or heat wave.
- Cooling is modeled; freeze protection and winter heating are not.
- Usage allowances are planning assumptions awaiting measured calibration.
- The estimates are not medical advice or manufacturer performance guarantees.
Versioning and reproducibility
Model 2.0.0 is recorded in every dataset row. Each build includes a UTC timestamp, dataset date, source status and permanent release snapshot. Changes to constants or formulas require a model-version change and entry in the changelog.
License and citation
The dataset is licensed CC BY 4.0. Cite the dataset version and model version, link to ArcticSoak, and describe outputs as modeled planning estimates. The data portal contains copy-ready citation text.