Firewood Heated Hot Tub | How We Built Ours

In this video we show you the process of creating the wood fire heated hot tub we created and installed at out remote bushcraft camp Katyusha. We went through a lot of trial and error with this build and wanted to share it with you. Leave comments and questions below!
See the hot tub installation video here: • Wood Heated Hot Tub in...
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[@achsahkaleb4844]

brilliant video!!! the little ring that goes over the copper pipe is called a farrel, the 3/4 inch to 1/2 inch adapter is called a polycob male reduser. From 56 year old lady in south africa that has built 3 houses literally with her own hands. God bless you!! Shalom

[@davegolding8861]

ferule

[@unionse7en]

Ferrule

[@OldNavajoTricks]

Olive is the nane I know, they're soldered or brazed in place then the lock nut pulls the pipe to tge connector when tightened.

[@xscreamskier24]

I made the same mistakes exactly. 1/2”, too many coils, not steep enough angles, etc. failed years ago. Revisited after this video and got it going!!! Switched to 3/4, shortened the length, and bam!

[@alexfranzwa6730]

What length did you end up with?

[@campkap]

As others have said, this is definitely the most helpful video on DIY wood-fired stock tank style hot tubs that I've come across! Thank you for sharing your findings as this will certainly help me out on my project this summer.

[@ryanbell6537]

Really appreciate hearing about the boiling wrecking the thermal siphoning!! Thanks a bunch!!

[@alexaguiar4636]

One of the most informative videos on this subject out there and I have seen many. Will add your knowledge to a rocket stove and hopefully have a warm jacuzzi

[@rodylima5947]

did you do it? im doing it this week

[@maxralfsson2592]

This video and this channel is great! I just now found your channel. How does this not have more views??!!

[@AnneLindyberg]

Beautiful job

[@robertslater5706]

Hey, great vid, if you add an inlet valve at the bottom of the coil so that you can put water in slowly via the hot coil this fills the tub slowly with hot water. It saves on time over all. You block the bottom entry to the tub(the cold outlet at the bottom) so that the water can only rise up through the heating coil. This is the method Dutch tubs use for the initial fill of hot water. It work much better because you don’t have to wait for the thermal siphon to take effect.

[@justinlyle7831]

Bad ass. I'm glad you shared your mistakes and the full experience. Not only makes for a more entertaining video but the obvious, i can learn from them.

[@mydogma7116]

Awesome thanks I'm going to try building one myself, got a nice salvaged 4 seater...

[@gemmabelfrage6691]

Thankyou so much inspiring 😍

[@angelsaucedo2231]

Im not much of a hands on person myself but for thoughts on a more permanent construction why not encase the coiling within a brick and mortar/ clay oven structure so the fire burns in it and its thermal mass allows it to retain more heat. Maybe also insulating the exposed piping. It might heat faster or consume less wood perhaps and increase the longevity of the piping? Looks pretty awesome cool method of hot tubbing

[@WoodsmanocD86]

Awesome video guys.. help me out loads .. cheers

[@dropbassnetwork]

thank you for posting this and the mistakes. saved me some money!

[@lukewarm2075]

Great videos do more guys

[@PhilEvansOnline]

Thanks for sharing. 👍

[@cedarcrapids1707]

these boys livin

[@Hotbottumz]

Cool idea 💡

[@user-sy7du4jm8u]

This is COOL!!!!

[@onionm1535]

Thank you so much for doing all of my homework for me! This is the BEST instructional video I've seen on off grid hot tub by far!

[@jamesontravis2650]

Sorry to be offtopic but does someone know a way to get back into an instagram account? I was stupid lost the password. I would love any tips you can give me

[@roninomari5741]

@Jameson Travis Instablaster =)

[@jamesontravis2650]

@Ronin Omari thanks so much for your reply. I got to the site on google and Im trying it out atm. Takes a while so I will reply here later when my account password hopefully is recovered.

[@jamesontravis2650]

@Ronin Omari It worked and I finally got access to my account again. Im so happy! Thanks so much you saved my account :D

[@roninomari5741]

@Jameson Travis happy to help :D

[@bobdinovo6889]

Thats sooo cool

[@robsoncruz5029]

Thank you! It helped me so much!

[@ReviewOutdoorGear]

Glad it helped!

[@sinsofman81]

Awesome video 👍.

[@Lazarus-aap]

Perfect! This is all I needed! So not too many coils and bigger tubing? Great video! Thanks

[@gfanslow]

Great video and thanks especially for explaining the mistakes you made. I'd like to put the coil down into a fire pit, but I can't drill a hole through the bottom for the cold inlet. So the cold pipe would need to go up over the edge and down to the bottom, do you think the convection is strong enough to have a siphon like this?

[@jimtepin4840]

Very nice. I would be curious about a more flexible pipe between the coil and the tank, just for more portability (assuming the fittings could handle it).

[@micjam1986]

You just save me a ton of time and effort...ty for posting.. God bless you too!

[@quintsaunders8093]

The heat transfer would likely be more efficient if you put the coals inside of a barrel. This would keep the wind from cooling the pipe, as well as maintain more heat and contain the fire.

[@ReviewOutdoorGear]

Agreed. I’ve since built an enclosure around the coil for this purpose. It heats up much faster now.

[@aengusgiblin2284]

Awesome

[@pewusinger]

Try using a brass one way piston at the bottom so the water will move in one direction only as soon as it starts to heat up in the coil.

[@hmooblomlomzemchannel3531]

Nice your video brother 😁👍🙏🤝💝

[@jawflorchannel7433]

Amazinggg

[@fallofmanbrand]

nice video bro

[@ReviewOutdoorGear]

Thanks

[@JasonRauschelbach]

I can't find the other video that you refer to on installing the tub in the woods but would love to see it.

[@ReviewOutdoorGear]

Link in the description 👆

[@jerryhansen5116]

I've done this but I incorporated a pump and have gotten water way too hot to get in. The only problem I had was a bit of vapor lock.

[@wirejacker81]

You said there was a formula for the length of the copper tubing versus coils and distance between the coils as well as the hot side of the tubing having a slight incline is there a formula? Where did you find this information?

[@flaquitoyork]

It will heat faster if you put the coil inside of a drum with so that less wood, higher heat and faster turn over

[@revid64]

Is there a “sweet” distance between the top and bottom inlets in the tub for water transfer? Was thinking of building one like this or building a tub with the back of a stainless steel stove directly in a tub. Obviously protected from anyone touching it.

[@kevindouglas8768]

Just get a small wood stove with a boiler system. They have a tank built into the stove. Also put a pump at the cold line so it doesn't get the hot water to deal with. BAM !!!

[@razingcanez717]

Can I do this with an in ground pool? I'm wanting to find out if the fire can be above the pool level.

[@SweetChillieBeat]

Wactha think about using that system to heat some tubes that run through a bench do you figure I could have a heated seat that way?

[@Dingerboys2]

Love the concept and trying it out but did you use copper fittings that come into contact with the galvanized?

[@ReviewOutdoorGear]

They are brass.

[@kennethshattuck4689]

Would you tell me how big was the galvanized tank you used in the video. Thanks and great DIY

[@ReviewOutdoorGear]

It’s a 2x6 foot tank.

[@karelleubner]

Hello, that is nice job, thank you! 🙂 Please, what was the temperature of the Cu tube near the bathtub at the output? I'd like to heat the water in te IBC container the same way and I hope it was not hot enough to destroy/melt it.

[@ReviewOutdoorGear]

No idea, but I would guess right at 85-99c, as water is not boiling on the way out

[@transcendtravel]

what would you say is the best height difference is between inlet and outlet? Thanks

[@joshsoorlin579]

Good showing the fittings, hardest part to find!!

[@TrentCamera858]

I have an acrilic plastic claw tub in my backyard hooked up to a propane water heater and i was thinking about building a fire pit near it to supplement the baths heat and because its cool. would it be a hazard to use the fire pit without the tub filled with water? fire risk?

[@BluIdBute]

Hey there! Great video! I’m going to be building my own “hillbilly” hot tub! I’m struggling with what type of copper piping to use. I’m seeing all different types (K, L,M, etc). Your link, above, takes you to 1 1/8” copper tubing. To confirm, you used

[@BluIdBute]

To confirm, you used 3/4” OD, yes? Any help with copper piping is appreciated!

[@crazysquirrel9425]

Insulate the tank and it will heat up faster. You might want to look into a tempering valve to see if that would be any benefit. IMHO you should have painted the tubing with grill paint.

[@poliacekjozef]

Slovensko Okej videjko 💯💯💯💯💯👌🇸🇰

[@michael-qq3gw]

Hi I'm using a plastic 1000L IBC the plastic connections it gets too hot on the outlet do you think it would work running the copper in from the top and under the water or does it have to come directly in at the side do you think ?? Handy video some good information thanks

[@ReviewOutdoorGear]

You could run it in over the top. The hot water outlet doesn’t need to be submerged.

[@michael-qq3gw]

I had it running in at the top before and it doesn't keep going because it wants to flow back then it loses water and shoot back out as Steam and burst of water 💦 and runs out the inlet then back out the top

[@ashleyevans5506]

I may have missed it but could you provide the link to all the fittings

[@anonymous_friend]

What if you put one tank inside a slightly larger tank and insulated the tub that way? I bet you are losing a lot of heat to direct loss to the ground

[@JasonRauschelbach]

Could a different tubing material work as well? Does the copper clean up well after use? Thanks guys.

[@josegomes6424]

Any tubing will work like copper,steel pipe bend it to your desire.

[@mikedavis1137]

FINALLY a great video on a hillbilly hot tub

[@1812bhw]

Building one now… wondering how many ft of 3/4” is optimal… 30’? Also wondering about the shape of the coil. I have a nice fire basket but the coil is smaller at the bottom to accommodate the conical basket.

[@ReviewOutdoorGear]

30’ is a great length. Also the conical design would work well.

[@NaeMuckle]

You can fit a no return valve that stops water returning back down towards the cold inlet.

[@davidwalker8359]

Yeah but won't the water be volatile and become explosive with steam?

[@NaeMuckle]

@@davidwalker8359 not if you have a pressure release valve.

[@davidwalker8359]

@@NaeMuckle makes sense, thanks

[@IRONREBELLION]

MAn I was having this same problem. really thin tube was just vaporizing the crap out of the water. also thinks for the tip on the recycle center

[@ReviewOutdoorGear]

Yeah, it was really frustrating. Glad we switched to the thicker tubing!

[@alanmcrae8594]

I think a one way check valve is supposed to fix that problem as it gives the warming water only one end to escape thru.

[@emilybomersbach3690]

Does the stock tank need to be raised off the ground? I saw another video where they placed it on wood like yours, but I also saw one where they made concrete footings, and then covered in gravel and sand. I’m trying to make something temporary (and cheap). Would some bricks laid on the grass work alright? Thanks.

[@ReviewOutdoorGear]

It doesn’t have to have any special footing. Bricks on the grass would work great.

[@123bluespinner]

@@ReviewOutdoorGear put down some blue insulation panels on the ground

[@ryanrobertson4001]

Great video, thank you. I am building one now. 300 gal tank +\~ . I have 1 inch tubing, about a 2ft coil, 7 coils, 5’ intake and out put. My question is: is it better to have the hot water in tube to be at the very top of the tank or is it okay for it to be 10 inches from the top? I don’t understand the dynamics of if there would be too much head pressure for the water to get into the tank? Any help is appreciated

[@ReviewOutdoorGear]

It’s okay to have it lower. Good luck!

[@jessebreyerb5082]

Check out a refrigeration supply store they will have what you need to pump it too

[@user-ue9iu2sb3w]

It’s a good video and idea,my only thing is how long is that copper piping gonna last,I’ve seen the copper wrapped around a tank providing the heat while the piping stays away from flames

[@ReviewOutdoorGear]

It’s lasted 4 years.

[@user-ue9iu2sb3w]

@@ReviewOutdoorGear ,not too bad,I thought it woulda been way sooner than that,ty for responding

[@dwightstebner2345]

could you regulate the flow of water enough to heat and fill the tub when filling with a pump. pump water direct through coil while heating

[@ReviewOutdoorGear]

Yes I think that would work. I’ve thought about doing that.

[@terry7491]

Copper has become much more expensive. Maybe I’ll put my much more expensive degree in mechanical engineering to use and cut out the re buy process lol. Good work

[@satansbiscuit]

Can I do the same sèt up as you guys but have both the inlet hose and the outlet hose both entering and exiting water by having the pipes both hang over the top of the tub rather than thru the sides?

[@ReviewOutdoorGear]

Maybe - this may not work very well, and you need to make sure that the hose connecting to the bottom of the coil is sitting in the bottom of the tank so that it will collect cold water that will then be heated up in the coil. The top hose can exit at the top or bottom.

[@k-dramagoodmorningseoul]

How have you been? Time has passed this year. I hope you take care of the cold weather and health based on Korea. ^O^

[@Dongerino.]

How long is the copper tubing at the end, when it works? Planning to build something similar.

[@ReviewOutdoorGear]

About 35-40 feet. Works great.

[@gammap6114]

Since the tub is metal, would that be quicker if the fire is below it. If the base of the tub is lifted up and give room for a firewood to burn and seal around the tub with soil to confine the heat (pipe the chimney away) do you think it would be more efficient?

[@ReviewOutdoorGear]

Yes, but moloch more difficult to regulate - it would be like sitting in a boiling pot. The button would be very hot to sit in. Smoke leak around the tub would be atrocious. But do give it a try and let me know how it goes!

[@mattfrick8038]

Would it work better for the life of the copper to just coil the copper around a steel drum? Be easier to contain the wood fire too.

[@cody481]

I found that the steel drum wrapped outside did warm the water but not as much as the copper tube inside the drum.

[@paulsmith4995]

It's a very hard invention too build a pool heater that works on burning wood and keep temperature in pool

[@thomasfilion9064]

I couldn't catch the part numbers. Lasko something to I could order them. I got a fiberglass regular bath tub that is the most comfortable thing as far as a tub I've been in I'm going to do it.

[@kerrylaneful]

what do you do to keep it from getting too hot? Do you ever take the fire off of it? Also doesn't the metal get hot?

[@ReviewOutdoorGear]

Just monitor the temp inside, and don’t feed the fire when it’s getting hot enough. The metal doesn’t get hot because it quickly passes off the heat to the water.

[@aliciahazzard6926]

Do you think this would work using an 8ft or 10ft stock tank? What changes would you make to accomodate the increase in size and capacity?

[@ReviewOutdoorGear]

Yes it will work. I would insulate the tub and put the copper tubing into a barrel to increase efficiency.

[@kevyt3095]

Should have run the filling water through the copper piping while filling it up, would have save a ton of time. everthing else is great! Nice project.

[@ReviewOutdoorGear]

Yeah we thought about that too. Would be a good idea.

[@EvrSpd]

I wonder what difference it would make to enclose the fire and coils around the sides to create a kind of oven and then to add thermal insulation to the hot pipe leading to the tub

[@ReviewOutdoorGear]

We have thought about enclosing it in a stove type set up.

[@chemistryguy100]

We recently built an enclosure around the cool and the heating efficiency has gone way up!

[@wirejacker81]

I got a question for you. On the second set of copper tubing when you used the three-quarter thicker pipe you wrapped it around what looked like a metal fire Container did you ever think of leaving the pipe wrapped around it and putting the wood inside the container and letting the heat transfer from the container to the copper piping so that you didn’t damage the piping after several uses?

[@carmencarnegie3399]

Hi like the video but what is the length of the 3/4 copper tube

[@ReviewOutdoorGear]

About 30 feet.

[@patbez01]

Do you have an easy trick or plan to empty the copper pipe during cold season, to avoid breakage?

[@ReviewOutdoorGear]

Yes, we tilt the tub on its side slightly and let the water drain out.

[@akapandeo]

How about lighting a controlled fire 🔥 below the tub and build a wooden contraption to sit and lean on🤔

[@ReviewOutdoorGear]

Believe it or not, that would take longer to heat the water. The surface area provided by the copper tubing combined with the heat transfer capability of copper allows the water to heat up much faster.

[@crazybob1954mo]

@@ReviewOutdoorGear HaHa Bullshit! You are No engineer.... The way you built it is stupidly inefficient. The majority of the heat simply goes up into the atmosphere. Tell me I am wrong... ???? 🤔

[@JesseDTF]

How has the copper pipe held up after repeated fires?/have you had enough fires to make any observations of 'long term' durability?

[@ReviewOutdoorGear]

Held up great so far. No issues.

[@jimmyjr52307]

Hook the water hose up to the coil and fill it up with hot water Then heat the water in the tank Little bit faster

[@Dingerboys2]

Where did your purchase the 3/4 in comp x 1/2 MIP. I can't find them anywhere

[@ReviewOutdoorGear]

Look in a farm supply store.

[@paulsmith4995]

How long will the cooper coil last I've heard stainless steel pipe is better too use as a coil I'm guessing this is how they build these pool heaters out of when buy them

[@ReviewOutdoorGear]

It will probably last 10-15 years. Been 3 years and no show of wear.

[@louiseharbick5670]

Where did you get the 3/4inch compression by 1/2inch male iron pipe adapter?

[@chemistryguy100]

At a local store specializing in hose and piping. It’s called House of Hose.

[@wtfbbqbye]

can you use 1/2 piping with a water pump hooked up?

[@michelkirsch2482]

Of course. Better with a pump. You get the energy from the fire sooo much faster in the tank

[@StringerCourier]

Watching your video, I just had this wild idea: How do you think it would work if I took a small galvanized bucket, filled it with hot charcoals, and suspended the bucket in the water opposite the end where I sit? It would be easier to keep the heat up in the bucket by just adding more charcoal.

[@danielbrown9532]

The bucket would radiate not circulate the heat like the tube. Circulation has more heat exchange then radiation. You would be overwhelmed by constantly adding charcoal to the bucket to keep up.

[@ReviewOutdoorGear]

Agreed.

[@davidwalker8359]

Sounds messy.

[@josegomes6424]

I think you should make a pizza 🍕 oven on the open fire 🔥 especially you have the copper pipe burning put it to use and you could have multi layer oven and you could sit back in your Dutch tub and relax with a shot of wine 🍷

[@chrisknightstravel]

Could the bath be made of plastic or wood?

[@raeleneeckmann2849]

How did you fill the tube with water? Did you truck it in, or by buckets.

[@ReviewOutdoorGear]

We have running water.

[@jimmonroe8532]

If you put two coils in the fire, do you think it would heat up twice as fast???

[@ReviewOutdoorGear]

Yes.

[@auhmsoogood]

Have you considered to build insulation around the tub to help prevent the loss of heat from the steel to the open air?

[@ReviewOutdoorGear]

Yeah I think I want to wrap it in the insulated bubble wrap!

[@auhmsoogood]

@ReviewOutdoorGear perhaps just insulated pink foam, it's ridged, but it won't pop, and they have a higher R rating. Then, potentially just adding dirt up the side for further support! Thanks for the video. It will save me a lot of mistakes and trouble shooting

[@rudebwoydread13]

Is there a pump being used? how is the water circulating? Maybe I missed that part

[@ReviewOutdoorGear]

No, there’s no pump, the circulation is due to heat with hot water rising due to being less dense than cold water

[@ryang5668]

How many feet of the 3/4 inch copper pipe did you need? Thanks

[@ReviewOutdoorGear]

About 35 feet.

[@stephencresswell4760]

Spend the whole video converting the temperatures into something the rest of the world understands. 🤣

[@ReviewOutdoorGear]

Bahahhahah

[@Lazarus-aap]

Weird thing is, when it comes to fittings, we use inches as well in the Netherlands... And about the temperature; you don't need to convert it, cause you can see that it works with water that was around freezing temperatures

[@libbysevicke-jones3160]

Same, why is America only one of three countries in the world that still use empirical measurements. I have to keep googling to know what he is saying. However after working 20+years in the plumbing and hardware industry- there is a lot of fittings manufactured in the USA, so in New Zealand where l am, our hardware stores carry both metric and empirical fittings. Don’t ask me what a pound is ???

[@darr3263827]

​@@libbysevicke-jones3160 agree. American here; and while I've been raised with non-metric, I'm more familiar than a lot of us yanks, and agree that a base 10 system makes so much more sense, and the fact that most of the world uses it makes me wonder why we don't convert. but, you you know how 'we' are. FREEDOM! We're always right and we're the best. But having traveled, it's always nice to know that when I see a sign saying how many km left to our destination, its gonna be quicker because Im used to Miles.

[@viktorwestergren4127]

copper and galvazined steel. wont it corrode?

[@baddonkey6876]

3:04 Farrell fitting Although I'm probably spelling it wrong but yeah, compression farrell fitting

[@ReviewOutdoorGear]

Yes you’re correct. It’s a ferrule. 🙂

[@johnathansparks1678]

Wonder if this could be done with a old hot tub that is not running...I see those for free every day that ends in Y on Craig's List??

[@user-sy7du4jm8u]

В натуре красиво!почти атомный реактор.!))

[@trouble11eleven]

Im in the north of Ontario canada, it gets super cold during winter, how would i go about with frozen water in the coil and pipes extending to the tub, would it just melt once id start a fire? Im worried that the pipes extending to my tub wont unthaw and can be a disaster I cant find anything online with anyone with experience with these builds and using during winter months.

[@ReviewOutdoorGear]

I would recommend you drain the tub between uses in that case or use a flame torch to melt the tubes leading away and to your tub

[@petepete66]

You can try .... fire 🔥 above .... tank 50 cm down under from fire .... so hot water is automatic running down into tank ...

[@crazybob1954mo]

HaHa... You Gots it Backwar Dummy....BaHaHaHaHaHa.... Fool....

[@felixromano3091]

How about putting the fire in a separate small tub full of water and connecting it to the tub people will be in with 2 large pvc pipe so the water in both containers get headed and the fire is a safe distance away