SAUNA. / M4 thermal readiness study
Study basis. Results require a controlled physical test.
M4 case study
Start warming before arrival.
Measure the warmer baseline.
M4 can be switched on remotely before planned use or operated for longer periods to maintain baseline warmth.
This study compares those modes with a cold start. It asks how the warmer starting condition changes the time and electricity required for the stove to bring SAUNA. to bathing temperature.
It is source-neutral. M4 may use a dedicated heat source or recover heat from another useful electrical process. The thermal result is assessed independently of that source.
No result is assumed. A controlled physical study is required before a readiness or energy claim is made.
Start M4 remotely.
Maintain baseline warmth.
Stove completes the lift.
Total energy measured.
The question
What changes when M4 starts first?
A cold sauna requires the stove to warm the cabin air, timber, glass, benches, stones, and other thermal mass before the bathing range is reached.
M4 can begin pre-warming remotely. The study asks whether the resulting baseline creates a meaningful improvement in readiness for the electricity used.
The stove remains the bathing heater and remains responsible for stones, steam, and löyly.
Scenarios
Compare starting conditions.
| Scenario | Starting condition | Final heating |
|---|---|---|
| Cold start | The sauna follows outside and site conditions. | The stove heats the full temperature difference. |
| Remote pre-warm | M4 is switched on remotely before planned use. | The stove completes the lift from a warmer starting condition. |
| Maintained baseline | M4 supports a selected baseline during reviewed operating periods. | The stove completes the lift when the sauna is required. |
| Recovered-heat baseline | A useful electrical process provides reviewed thermal output. | M4 retains or routes the heat before the stove is used. |
Measurement
Measure the complete preparation period.
| Input | Recorded basis |
|---|---|
| Outside condition | Air temperature, wind, and relevant exposure during the test. |
| Starting condition | Cabin air, benches, glass, timber surfaces, and other relevant thermal mass. |
| Baseline input | M4 thermal input, operating duration, and electricity used. |
| Stove input | Stove power, operating duration, and electricity used during the final lift. |
| Readiness | Time from stove start to the selected bathing temperature. |
| Retention | Temperature change after M4 stops and before or during stove operation. |
| Total energy | Combined M4 and stove electricity for the complete preparation period. |
Stove electricity alone is not enough. The comparison records the combined M4 and stove input from the beginning of preparation until the selected bathing temperature is reached.
Site conditions
The result belongs to the site.
| Condition | Influence |
|---|---|
| Climate | Outside temperature, wind, solar gain, and seasonal variation. |
| Envelope | Insulation, glazing, airtightness, and thermal bridges. |
| Ventilation | Required airflow and heat lost while the sauna is prepared. |
| Thermal mass | Timber, glass, benches, stones, and internal surfaces that absorb heat. |
| Operating pattern | How often the sauna is used and how far in advance readiness is required. |
| Heat path | Where lower-temperature heat enters, how it moves, and how much is retained. |
Results from one climate, envelope, or operating pattern should not be presented as a universal SAUNA. performance figure.
Reading the result
Readiness and energy are separate.
| Measure | Interpretation |
|---|---|
| Faster readiness | A warmer starting condition may reduce the time required for the stove to reach bathing temperature. |
| Stove electricity | The stove may use less electricity during its final lift because it closes a smaller temperature gap. |
| Total electricity | Baseline heating uses energy. The combined M4 and stove input must be measured before claiming an energy reduction. |
| Operating value | A site may value predictable readiness even where total electricity use is unchanged or higher. |
Faster readiness may be the strongest result even where the total electricity comparison is neutral. Energy reduction should be stated only when the complete measured preparation cycle supports it.
Heat source
Use available heat where it is useful.
| Source | Role in the study |
|---|---|
| Dedicated electric heat | A simple reference source for establishing the thermal effect. |
| Available process heat | Heat already produced by a useful electrical process at the site. |
| Recovered compute heat | A controllable compute load where both the computation and heat have a real use. |
Electrical computation produces heat while operating. A controllable compute load can therefore provide thermal input where both the computation and the heat have a real use.
Bitcoin computation is one available implementation. It does not define M4, the thermal study, or the customer value proposition.
Historical note
One earlier implementation.
An earlier 2020–2025 model used a 1.1 kW Bitcoin-computation assumption to examine one form of controllable recovered heat.
That calculation is retained as an internal historical reference. It is not a forecast, financial guidance, or the basis of the current M4 proposition.
Project review
Confirm the complete system.
| Review | Basis |
|---|---|
| Electrical | Supply, protection, isolation, controls, and compatible equipment. |
| Thermal | Output, temperature limits, retention, routing, and safe heat rejection. |
| Physical | Airflow, enclosure, clearances, acoustics, and service access. |
| Operation | Schedule, monitoring, failure states, maintenance, and responsibility. |
| Stove separation | M4 does not remotely operate the sauna stove. Stove operation remains subject to its approved control and safety system. |
M4 is included only where the heat has a real use and the complete electrical, thermal, physical, and operating arrangement is confirmed.
Remote operation starts M4 only. It does not start or control the sauna stove.
Next step