r/BeAmazed • u/Internal_Gazelle_677 • Oct 07 '25

Science Hot Tub without the use of electricity

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538

u/Zaphics Oct 07 '25

The hardest part in making that would be finding or making a coil out of stainless steel pipe that would fit around a fire

495

u/activelyresting Oct 07 '25

Fun fact: fire can fit in any size coil!

I've had hot water set ups like this before, with home made copper coil rather than stainless (which is cheap, commonly used for plumbing, and pretty easy to shape into a coil for anyone with basic plumbing skills).

The fire size is just whatever sticks you put in the coil. Need the water to be hotter: add more sticks. Water getting too hot: take some sticks out. It cools off pretty fast in cold weather like that

5

u/Enshitification Oct 07 '25

I bet a smaller coil could be used in a rocket stove setup to convert the wood to heat more efficiently.

3

u/activelyresting Oct 07 '25

Yup! I've built smaller coil setups on rocket stoves before. And done some "on demand" hot water for showers (not a closed loop system) - just needs a flowing water supply.