The numbers, worked out
7 calculators for the figures that actually decide a recovery room: what it costs installed, how much ice a plunge swallows, how many minutes a dose takes, how many kilowatts a room wants and what circuit that implies, how long the room takes to heat in January and what a session costs in electricity. Each one shows its formula and names the source of every number going into it.
None of these tools runs on our own bench data yet. Every one says so on its own page, and names the measurement that would replace the figures it borrows.
Home Saunas
All home saunas guides →Session estimator Literature-sourced
How many calories does a sauna burn?
The MET arithmetic with the formula printed, the sweat loss in liters and pounds, and the plain finding that a sauna session lands near sitting-still territory rather than near a workout.
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Sizing tool Manufacturer-sourced
What size sauna heater do I need, and what circuit does it need?
Room volume to kilowatts to amps to breaker to conductor gauge to what the circuit costs. Every sizer on the internet stops at kilowatts; the circuit is where the budget is decided.
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Heat-up model Manufacturer-sourced
How long does a sauna take to heat up, and what does winter do to it?
Every spec sheet says 35 to 45 minutes and never says from what temperature. Run your room, heater, stones and weather through a heat-loss model that prints every constant, and see the same room in January — including whether it gets there at all.
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Cold Plunge
All cold plunge guides →Red Light Therapy
All red light therapy guides →Recovery Room Builds
All recovery room builds guides →Cost estimator Manufacturer-sourced
How much does a home sauna cost, installed?
Equipment plus the circuit, the pad, the permit and the first year of electricity — the four line items the brands leave off the product page. Cold plunge on the same page.
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Running-cost tool Manufacturer-sourced
How much electricity does a sauna use, per session and per year?
Kilowatt-hours and dollars per session, month and year for your sauna, your habit and your rate — with the hold duty cycle derived from the room's actual heat loss instead of guessed, so January costs more than May the way your bill will. It ends on the comparison that matters: the circuit costs more than the electricity.
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Every tool, and the guide it belongs to
| Tool | Answers | Hosted on | Inputs sourced from |
|---|---|---|---|
| Installed-cost estimator | How much does a home sauna cost, installed? | Manufacturer-sourced Equipment prices are manufacturer and retailer listings, and the warm-up and hold duty behind the running-cost line come from a heat-loss model calibrated to a manufacturer's warm-up figure, not from a meter. | |
| Ice calculator and chiller payback | How much ice do you need for an ice bath? | Manufacturer-sourced The loss allowance and the chiller pull-down times behind the payback table; the underlying thermodynamic constants need no bench. | |
| Calorie and sweat-loss estimator | How many calories does a sauna burn? | Literature-sourced Sweat loss per session on a bathroom scale, and a published MET value for sauna bathing, which does not appear to exist. | |
| Dose and distance calculator | How long should a red light therapy session be? | Manufacturer-sourced Panel irradiance at 6 in and 12 in on a spectroradiometer, for every panel in the catalog rather than the three whose maker publishes one. | |
| Heater sizer and circuit chain | What size sauna heater do I need, and what circuit does it need? | Manufacturer-sourced Time to setpoint for a sized heater in a real room, which is what would put error bars on the kW-per-cubic-foot convention. | |
| Heat-up time and the winter penalty | How long does a sauna take to heat up, and what does winter do to it? | Manufacturer-sourced A logged heat-up curve — four K-type thermocouples at sensor, top bench, lower bench and floor, five-minute intervals from a cold start to setpoint — in a real room at a known outside temperature. The model on this page is calibrated to Redwood's stated 35 to 45 minutes, which is a manufacturer's figure at an unstated starting temperature. | |
| Electricity per session, month and year | How much electricity does a sauna use, per session and per year? | Manufacturer-sourced A kilowatt-hour meter on a real heater circuit through a cold-start warm-up and a held session, at a logged outside temperature. The warm-up minutes and the hold duty here come from a heat-loss model calibrated to a manufacturer's warm-up figure; the electricity rate is a state average until you type your own. |
Every calculator renders a worked answer in plain HTML before any script runs, so the page is complete with JavaScript disabled — the inputs enhance it rather than supply it. Nothing here is medical, electrical or financial advice.