Guides
The background behind the calculators — what the numbers mean, and what actually changes them.
- What a home sauna really costs to run
Why the common "kilowatts times hours" estimate is too high, what a session actually costs, and how to cut it.
- Is a 120-volt hot tub enough in winter?
A plug-in hot tub heats at a quarter the speed of the same tub on 240 volts. It costs the same to run, but here is when it can't keep up with the cold.
- How sauna heater sizing actually works
The 1 kW per cubic metre rule, why glass and stone break it, and how to read a manufacturer's chart without getting caught out.
- What wiring does a sauna heater need?
Amps and wire size for 3 to 8 kW sauna heaters at 240 volts, taken from two makers' manuals, plus the breaker rule and the one device to leave off.
- How much does a hot tub cost in winter?
Monthly kWh and cost for a 400 gallon hot tub at 70, 50, 30 and 10 °F outside, which winter changes save money, and why turning it off is the wrong move.
- Where a hot tub's electricity goes
Standby heat loss, not bathing, is most of a hot tub's bill. Here's the split, and the three changes that measurably reduce it.
- Sauna or hot tub — which costs more to run?
A side-by-side of what each actually costs per month, why the answer surprises people, and which one suits how you would really use it.
- Your hot tub cover is the whole bill
How to tell if a cover has failed, what a waterlogged one costs you each month, and what to look for when replacing it.
- How long a hot tub takes to heat
Why a fresh fill takes most of a day, what changes the answer, and how to tell when your tub simply will not reach the temperature you want.
- How long a sauna takes to heat
Typical heat-up times by heater size, why insulation matters more than kilowatts, and whether a hotter sauna is worth the wait.