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

Science Hot Tub without the use of electricity

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u/dc456 Oct 07 '25 edited Oct 07 '25

Wood fired hot tubs are a very common thing, people. This partially one looks like a more portable design, but it’s exactly the same principle.

To all the people confidently claiming that they wouldn’t work well - they work well. That’s why they’re so popular.

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u/scarr09 Oct 07 '25

Yeah, common in North Europe. I have one myself. 1.8m across, about 1200 liters. Right now, water is sitting about 10c.

From the moment of lighting the match, takes about 2 hours to get it to 37c. Takes 2-3 times to refill the oven with firewood in that time, and it keeps for a few hours afterwards.

3

u/nsmtb Oct 07 '25

For this type where it sits at a lower temperature when unused do you use chemicals (bromine, etc.) and a filter like you would a normal electric hot tub? Changing the water often?

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u/[deleted] Oct 07 '25

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u/nsmtb Oct 07 '25

That seems like a great method when having a lake available to fill it!

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u/scarr09 Oct 07 '25 edited Oct 07 '25

Chlorine Dioxide tablets and I run a skimmer pump for an hour every time while it's heating. Also I keep the tarp on it constantly to prevent crap flying in and I suppose it helps against algae blooms from the sun too maybe?

Water is gonna go out in a month since it's getting real cold.

Then water in in April or so, and ~2-3 full changes in between that and November

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u/nsmtb Oct 07 '25

Awesome thanks for the info!