Stainless Steel Coil Heat Exchanger for dutch tub,Wood fired hot tub heater coils

Sell Stainless Steel Coil Heat Exchanger for dutch tub,external wood fired hot tub heater coils,let you commerical-manufacture or DIY a wood  firing hot tub or bath pool.By burning firewood pieces heats water in tub to be an off grid hot tub immediately.

Material: made from stainless steel food-grade 304,salty water resistant,anti acid, anti alkali and anti-corrosion in outdoor enviroment long years;

Size: Standard type is made of OD25mm pipe,8 circles.Coil outer diameter 35cm and height 30cm. Accept customized size with pipe OD.32mm,40m mand 50mm.

Many options with different accessories to fit your demand in different occasion.See below introduction.

Place of Origin: China. Sell to to worldwide, Ship by air plane or by sea boat;

 Enquiry/ Order / Review on the ” Hot Tub Coil Kit”

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A video on “SS Coil Heat-Exchanger for dutch tub,wood fired hot tub heater coils”

This video was recorded by one of our customers from Australia who brought coil heat exchanger for hot tub from Smartclima.

Stainless Steel Coil Heat Exchanger for dutch tub

Purchasing options on “SS Coil Heat-Exchanger for dutch tub,Wood fired hot tub heater coils”

Smartclima is s specilized manufacturer for external wood fired hot tub heater coils which can be supplied as following options: (we also accept customized production)

Type A Option 1A:Heater Coil  only;

Hot tub heater coil option 1A coil only
Buying Option: Type A Option 1A,which includes SS hot tub coil only,no have other accessories.


Type A Option 1B:Heater Coil  +Supporter+ Fire holder;

Hot tub heater coil option 1B coil kit
Buying Option: Type A Option 1B, which option includes heating coil,ground stand supporter and wood burning / fire holder;(height can be 100mm, 150mm,200mm and 300mm, the default height is 200mm).

Installation instruction: Type A Option 1A is the coil heater only,non-includes any other parts. And Type A Option 1B includes coil heater,ground stand(coil support) and wood fire holder.The two options can meet most customers` requirement on DIY making their own hot tubs. When installs,just use a hose to connect your tub fittings and the coil`s end.No other procedures. Notice:when you drill hole on tub wall, assure the upper hole must be lower than water level in tub,which can help to improve heating effience and reduce heating time.

Type B Option 1A:  Heater Coil  only + Water flowing control valve;

This is coil heater type B option 1A
Buying Option: Type B Option 1A,which option includes SS coil and T control valve that can control water flows in pipe.


Type B Option 1B: Heater Coil  +Water flowing control valve +Support+ Fire holder;

wood fired tub coil heater type B option 1B
Buying Option: Type B Option 1B. This option includes SS coil ,T control valve and floor standing support (height can be 100mm, 150mm,200mm and 300mm, the default height is 200mm).

Installation instruction: Type B Option 1A is the coil heater with stop valve and water inlet faucet inlined,from which the tap water can flow into the coil and your tub. Type B Option 1B increase the fire burning holder and coil ground supporting. For type B coil kit comes with a brass control valve with in-water quick connector.  The brass valve is used to let you control the water temperature in tub:when feels water too hot,just shut off the valve,and the water stop flowing immdiately to prevent water temperature in tub from rising. The quick connector is used to let you connect water pipe to water source faucet.After irrigate the water to a suitable height( usually need to be over than the upper pipe port),just shut off the small valve`s handle.

Type A Option 2A: Heater Coil + Detachable Flanges;

wooden fired tub heater coil option 2A
Buying Option: Type A Option 2A,which includes one coil and two detachable flangers.


Type A Option 2B: Heater Coil  +Detachable Flanges + Supporter+ Fire holder;

wooden fired hot tub heater coil option 2B
Buying Option: Type A Option 2B, It includes heater coil, two flanges,wood firing mount and ground supporting bracket.


Type B Option 2A: Heater Coil + Control valve +Detachable Flanges;

wood burning tub coil heater type B option 2A
Buying Option: Type B Option 2A,this option contains one coil with water flow controlling valve and two detachable valve.


Type B Option 2B: Heater Coil  +Control valve + Detachable Flanges + Supporter+ Fire holder;

DIY wood burning hot tub`s parts coil heater type B option 2B
Buying Option: Type B Option 2B

Installation instruction: For Type B Option 2A and Type B Option 2B, by controlling brass stop valve, you can control the water temperature in your tub (when too hot,just stop off).

Type A Option 3: Coil Kit,Comes with accessories(See below description):

Stainless steel hot tub coil kit option 3
Buying Option: Type A Option 3, includes one heater coil,two flanges,ground support,fire holder and smoke and wind guard,all-in-one kit!


Stainless steel heat exchanger coil for wooden fired hot tub option 3
Buying Option: Type A Option 3


Type B Option 3: Coil Kit,Comes with accessories(See below description):

DIY wood burning fired hot tub part coil heater type B option 3
Buying Option: Type B Option 3, includes one heater coil with brass stop valve,two flanges,ground support,fire holder and smoke and wind guard,all-in-one kit!
The option 3 kit includes:
  • SS coil,used for heat the water in tub;
  • Detachable stainless steel flange,to install the coil onto the tub with fasteners;
  • Smoke Guard,prevent smoke blow to the person who are soaking in tub;
  • Wind Guard,prevent fire heat blow to the air.This guard is helpful to keep heat and improve coil working effience;
  • Wood Basket/holder,to hold burning wood under the coil,hold fire;
  • Water flowing stopper.When the heater coil is working,maybe you will feel the water in the tub is hotter and hotter,and then you want to prevent the water into the coil from heating.Then,you can use this accessory-water flowing stopper,very easy to use and stop the water flow into the coil immediately.A very useful item.
  • Ground stand.(If no special requirment,will delivery height 250mm).

Type A Option X: Heater coil + Flexible extending hose + Attached flange valve,(options:  fire holder; ground stand)

Option X comes with tank/tub/barrel connector kit as following,and use high-temperature-standing rubber hose to connect heater coil and tub. This design is widely used when DIY your wood burning hot tub. The connecting kit has ball valve,when the water in tub is over heat,you can close off this valve,easy to use.

wood burning coil heater with connector
Buying Option: Type A Option X
fired heating coil for hot tub with connecting tube
Buying Option: Type A Option X

The following instruction photo to show you how big hole you should drill in your tub wall:

tub tank or barrel connector
For 25mm coil,you should drill 40mm hole; and for 32mm coil,you should drill 48mm hole.


Type B Option X: Heater coil + Control valve + Flexible extending hose + Attached flange,(options:  fire holder; ground stand)

DIY hot tub part coil heater with valve
Buying Option: Type B Option X, includes heating coil,brass control valve,rubber hose(length 50cm), and attached valbe.

Installation instruction:For 25mm coil,you should drill 40mm hole; and for 32mm coil,you should drill 48mm hole.


Twin type: two coils plus connecting kits as below:

twin coils to heat large swimming pool

Installation Instruction:twin type is usually used for heating large bath tub or swimming pool,it can speed up heating large volume water. You just need to open two holes on tub wall as inlet and outlet port, then connect to tub.That`s all!

Add-on kit–Roasting/Baking/Cooking grille ( It is optional part,if you also need it,please let us know).

The coil heater should be not only for heating your tub,it should do more works.And so, Smartclima explore more functions.Check below images,the add-on kit—Roasting/Baking/Cooking grille can let your heater have Roasting/Baking/Cooking function immediately.Especially,when you need to put in wood into coil,just onely need to move the grille away,no need to take it off again and again,very  easy to operate. The kit is made from food grade stainless steel,not rust.

Add-on kit-- Roast grille for hot tub coil the roast grille can be rotating away not only for heat tub but also can bake cook

 Product details for “Wood burning hot tub coil”

Coil details:

SS Tube size:Tube diamater 25mm * 1.5mm wall thickness
Size of coil part: Dia.35 * 30 height (cm)
Tube end:Threaded.
Circles:8 circles.
Supporter height: 25cm(if you require other height,please let us know when place order).
Notice:The below pictures are just for reference
Package:1 unit / package.
* We also accept your special size to customize coil for you.


stainless steel polished-pipe

hot tub tread with cover protector

Water flowing stopper for heater coilDutchTub-GrillingDIY-hot-tub-duct-tube

Benefits of a fire hot tub heater coil made by Smartclima

1. The heater spiral coil is made of seamless stainless steel (304) tube and can withstand high pressure.

2. Cleanliness and health.As the material is food grade stainless steel 304,no harm to bathing people in tub.

3.Long service life.As the heater coil is made from quality stainless steel tube, it is anti-corrosion, and thus, it is the best choice for the outdoor environment.

4.It is not heavy, easy to transport, and a good choice to build a portable hot tub for camping experience.

5. For manufacturing, we can process it into any shape and size of your design. Customized dimensions are accepted.

6.Nice looking. The surface is polished and meets food grade standards.

7.A smooth inner surfac,no wrinkle and a small pressure drop allow water to flow and circulate in the coil peacefully;

8.Excellent temperature resistance, can prevent frost cracking evaporator in low temperatures, and can work safely at minus 270 °C to 400 °C.

9.With stainless steel flanges to attach to the hot tub;

10. With all the accessories for you to build a complete hot tub.

11.Give you a good outdoor bathing experience. Enjoy your spare time.

12.Easy to install and free maintenance: When you get the coil,just need to connect with your tub;And just put the wood pieces into the coil,fire it.Ok,finish,no more steps.


[1] Stainless steel has strong material strength. The tensile strength is better than other materials.

[2] Stainless steel heat exchangers have many advantages, such as strong pressure, stability material properties, high heat transfer efficiency, won’t contaminate the medium and no refrigerant leakage.

[3] Stainless steel has excellent temperature resistance and can prevent frost crack evaporator in low temperatures, operating safely from -270 °C to 400 °C.

[4] Stainless steel has good mechanical properties and good hot work ability for stamping and bending, and no heating treatment hardening.

[5]It can be attached to a fiberglass soaking hot tub, a portable waterproof cloth tub, an old-fashioned tin tub, a wood tub, or any other bath tub.

[6] principle: The basic coil was housed in a heater where firing and fire inside the coil produced heat and exchanged heat with the water recycling inside the tube. It can be used in a straight-sided bath tub.

Application of Wood fired hot tub heater coils :
These coils are used as heat exchanger for homemade construct wood fired outdoor hot tub,putting at your backyard,backgarden or for backcountry camping,enjoy your fired soaking bath!

Wood Fired Thermosyphon Heater,hot tub heat exchanger,burning a fire with wood outdoor in coil,as the best important part designed especially for  dutch tub,Pool Heater ,and wood fired outdoor hot tub,burning a fire in the coil to heat cool water,used as heat exchanger,utilizing thermodynamic nature circulation cycle principle to heat the water in the tub,circulate the water through the coil(water comes in at the bottom of coil,heats up,and thus absorb heat energy from hot coil tube,and then flows out at the top back into the tub),thus also named Hot tube heater coil.

Made from polished stainless steel with high heat exchanging effience and perfect heat transfer efficiency performance,stability material properties.Has excellent temperature resistance , can prevent Frost Crack evaporator in the low temperature ,will safely working at minus 270 Deg C to 400 Deg C.Maximum Working Pressure:4.5Mpa,can heat more than 200gallon water.

wood fired coil heater

We are proud to annouce that Smartclima is the earliest designer and developer for the coil heater used on wood fired hot tub.And also,we are the best professional and largest manufacturer for this product in world!

How to order “Fire heated hot tub coil”?

  • The external wood fired hot tub heater coils are available for retail and wholesale;
  • The item takes large packing dimension,therefore,takes much volume weight.The place of origin is in China,when you buy one or two,please consider freight(by air or by sea) into the cost;
  • Accept bulk order with container delivery;
  • Pls indicate us the quantity you need,so that we can calculate the shipping charges;After you confirm the price,we`ll send the invoice via Paypal for you to pay.
  • Please contact us to email:
  • To today,we already sold out more than 3000units Stainless Steel Coil Heat Exchanger for dutch tub,and get 100% positive feedback! 

F.A.Q concerning for “SS Coil Heat-Exchanger for dutch tub,Wood fired hot tub heater coils”

What is Wood Burning Coil Heater For Hot Tub?

The fired hot tub with heating coil works depending on the principle of natural hot circulation.The coil of burning wood pieces heats the water,the hot water goes up and is forced to the tub through the spiral coil. At the same time,the coil's bottom entrance draws in cold water from the tub,because the cold water always sinks.During this cycle,the water in the tub becomes more and more hot without electricity power or gas to drive.

Can I DIY construct my own hot tub using this wood burning coil heater?

Yes,of course. You just need to prepare for a bath tub and a driller, and the coil kit including all other accessories will do rest works for you. If you want to have a complete set of tub+coil or portable type to use anytime anyplace,just leave message to us,we can help.

How long should I wait to heat up my wood fired hot tub?

The heating time of the tub is affected by the volume of water in your tub,and also is affected the temperatures of the water and the surrounded air.With our test,using tub with 0.80CBM or 200 gallons. water,it takes about 1.5 hours to heat up from 18°C (64°F) to 40°C (104°F maximum suggested temperature), or about 2 hours if the original temperature is around 13°C (55°F).Of course,if you can do some insulation work arround your tub,heating time can be reduced.In addition,a very important factor is that the upper outlet must be lower about 5cm than the water level in tub,which can speed up heating water.

Can I use copper pipe to make this coil heater?

Yes,but no necessary.At the begin minutes,copper is fast to heat up, but after 5 minuts,stainless steel can reach the same heating performance and speed as copper pipe does.And also,you know,copper will take much more cost than that made from stainless steel tube.Another possible problem is that the copper tube will melt and become deformed after long-time burning,but stainless steel tube wouldn`t.

What is best feature of this coil heater?

After do much reseaching work and many tests,finally to choose this special stainless steel tube to fabricate with perfect parameters and best performance of heating transference efficiency.In adition,it is food-grade,long service life,especailly can work with salt or marine water.Different with electrical heater or gas burning heater, this heating coil doesn`t require any other power,just need some solid wood blocks.

At what temperature can the coil work? it may be used in temperatures as low as 0℃?

The coil heater is made from special stainless steel,and so,no problem to use it under 0℃. But if used in very cold days which will have ice,we suggest you to drain out inner water after bathing which can help prolong its service life.

How many persons can soak in tub with this coil?

It depends on your tub volume.If your tub is big enough,then it can work for 4 adults or 6 children.Of course,the bigger your tub,the longer time to wait.

What is the best way to manage the water's temperature?

To maintain the proper temperature, one way is to stop adding wood pieces to the fire after it reaches your desired level of heat.There is plenty of time to respond if the water temperature begins to become overheat. The other way is that,if you require,we will also can equip a stop valve for the heating coil kit (See above Option X). Once it reaches your desired temperature, you can switch off the valve. Then the flow of water will stop immediately, thus stops the temperature in the tub from rising.

General Knowledge on “Stainless Steel Coil Heat Exchanger for dutch tub,Wood fired hot tub heater coils”

principle Wood-Fired-Hot-Tub-workingThe external wood fired tub heater is a thermosiphon device,it is a heat exchanger which works depending on the principle of natural hot circulation.  Natural hot circulation refers to: in a closed system,depending on density difference between hot and cold water,to form circulating liquid to drive an energy transmission. In the dutch tub coils,the cold water flows into the bottom tail pipe,and goes up in form of spiral state,during this process,absorbing fire heat to let the water inside gradually become hot,and finally flows into the tub.During this cycle,the water in the tub becomes hotter and hotter…For DIY your own outdoor hot tub,please refer to this article.

The wood fired Hot Tub,used as hot tub heat exchanger, was just to utilize the Coil Heat Exchanger works depending on the principe of natural circulation to heat water to have a bath.

Without electricity or gas burning, some persons can enjoy bathing together in free and relax yourself at most.

This simplicity still appeals to many people. But also the rituals around it, like gathering the wood, burning the wood, regulating the stove and the heat, mixing the water up front. And then enjoy the rising steam and noises from the heater…….

In that respect a Wood fired Hot Tub is a total different product compared with the Jacuzzi from today which is working on electricity.

What is a Wood fired Hot Tub? A Hot Tub generally consists of the following components:

A heater or stove (made of stainless steel) being a sort of metal container below the water in which you can burn the wood. This heater has 2 openings that are above the water, 1 for air and landing with a wooden lid with wooden handle, and 1 for smoke exhaust.

A chimney connected to the air pipe of the stove. This is a long metal pipe with a cap that serves as a spark arrestor.

A protective panel around the stove protecting you from burning on a hot stove.

Benches all around, so you can sit and relax. On request benches are removable for cleaning purposes.

Drink holders depending on the model attached to the cap of the stove, sometimes attached to the exterior. You can keep your drink or snack at a place holder.

A ladder, to be able to take place in the wooden bathtub.

A lockable wooden lid, Wood-Fired Hot Tub at the end when you can not use it. This prevents such leaves may fall, or insects get in the water.dutchtub-works

A stop so you can dirty water drains and evt. aanluitmogelijkheid one can achieve in the stormwater or sewer for dirty water.

Stainless Steel Coil Heat Exchanger for dutch tub,used as tub heater, is the rings around the Tobbe Tobbe which you can sue. Suppose that Tobbe has shrunk slightly in dry weather, you can tighten the straps slightly. On the stove side you can usually tighten the straps. This is a great product!

Helpful articles or resource on “Wood fired tub heater”

Enjoy outdoor hot bath

Want to enjoy an outdoor hot bath or during campfire life with an external wood fire coil heater (as picture shows),no electricity,no gas burning? For many people, this is a romantic, luxurious and inaccessible lifestyle. However, this becomes possible if you are having a wood fired hot tub and it is not difficult if you have heater coil. So in the following article, we will share steps how to DIY a wood burning hot tub.

First, prepare for the following materials and tools:
A bathtub. You can get a bathtub from various channels, you even can also use an old bathtub to retrofit it, or you can use wood pieces to organize and build a bathtub yourself.

Some copper pipes or stainless steel tubes and water tank connectors.The diameter of copper tube should be bigger than 19mm in order to have a good heating speed.

Prepare a drill for drilling holes on the bathtub.Alternatively, you can add an optional drain plug to the side of the bathtub near the bottom so that you can easily drain water as needed.

The following steps you can follow:
1. Choose where to build the hot tub.From the simplest perspective, you must decide where to build the bathtub. If unsure, look for an area that will not affect the house or its light at all, preferably near to water. Of course,if you want to use in camping,then the tub must be portable and not too heavy.

2. Prepare the ground.Once you decide where to build your bathtub, you need to level the ground and remove things like spikes that could damage the bathtub. Then place the bathtub on that flat ground.

3.Make a heating coil or diy heat exchanger for hot tub . You can use copper tube to bend to be coil to heat the water in the bathtub. Or you can buy a good Stainless Steel Coil Heat Exchanger for dutch tub  directly from Smartclima, it has a more reasonable design,peaceful flowing and heats up faster,it looks more beautiful.

4. Drill holes on the tub or tank.Use a driller to make holes on the wall of bathtub or water tank. The size of the hole should match the size of connection kit. The position of the hole should be determined according to the position of the inlet and outlet pipe of the heater coil.But notice to let the water outlet keep under the water level in tub,which can speed up the heating time.

5. Add accessories. Put the water tank connection fitting through the hole and sealed it with a silicone sealant. Then connect the heating coil and bathtub connector with a high temperature resistant water pipe.The ends of your own heating coils may be slightly bent, so trim them before inserting them into the accessory. Put some bricks under the coil heater so that the height of the coil is consistent with the height of the hot tub hole.

Done. Then fill the bathtub with water and burn wood blocks in the coil. Note that the height of the water in tube should be higher than the opening hole in the bathtub, this can greatly shorten the heating time.

Improvement ideas:

It is recommended to use plastic bathtubs or wooden bathtubs, as this will help to save wood.
Creating a stove-like enclosure around the coil will make the system more fuel efficient and help draw the smoke out of the barrel.
If the cost allows, it is recommended to increase the number of coils, which will speed up the heating.
It is recommended to use larger diameter copper and stainless steel pipes to increase the heating rate.


Stainless steel coil heater for wood burning fired hot tub and dutch tub,Direct-sale by manufacturer
Stainless Steel Coil Heat Exchanger for dutch tub,Wood fired hot tub heater coils 1

Sell coil heater for you DIY wood burning fired hot tub, Direct-sale by the earliest designer and largest manufacturer for wood fired heating hot tub coils in world.

Product SKU: SC09726941

Product Brand: Smartclima

Product Currency: USD

Price Valid Until: 2030-12-18

Product In-Stock: InStock

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Enquiries or Reviews

  1. Nya

    I want to retrofit my traditional tub driven by electricity to be an off-grid tub.The idea introduced here seems very good.

  2. Zackery

    how long time can I get these heaters? Need it urgently.

  3. Adrienne

    I want it to heat my homemade tub.My plan is to put the tub in house but put the coil kit outdoor,and thus it need pipes to connect both. The option X seems better,I also need fire holder and ground shelf.thank you.

  4. Amy

    I would like to know cost of stainless coil (prefer 1.5″ tubing, 12″ tall and 14″ diameter coil with 14″ ends)…..Cost of shipping to 98584 and projected shipping date. This will be used for 750 gallon tub and should also have fire holder and wind-screen please.

  5. Chenliky

    I`d like to know how long time to heat a tub by using this coil device?

  6. Aprianna Adi

    We are a factory to produce all kinds of tubs in Ireland,and we are going to develop hot tubs heated by wood fire burning.Can we have your catalog for all parts?

  7. Matt

    Hello, can this be used for a large inground saltwater pool? What is the material of the piping?Will this have any reaction to any of the chemicals that go along with mainting pool and if this can be used what is price for the setup with double coil and feet and wind guards.

    • admin-smartclima


      Yes,the twin type can works for salt water,as it is made from stainless steel,which has very good performance of anti-corrosion.

      Two pcs composed one twin kit. Please let me know how many kits you need? and then we can quote to you.

  8. Bri-Guy

    I need these external coil kits to heat tubs in my rural tourism resort.

  9. Tim

    Interested in twin type with connector prices for pool

    • admin-smartclima

      Hello,when we replied to your email,it was returned.Systsem mentioned that your email address is wrong. Please write message to our email:

  10. Karin L. Larson

    Could you manufacture a hot tub coil made from copper pipe? Thank you!

  11. Steve

    Hi there… interested in the heating coil (with threads)… can you please send me information including pricing for one being sent to New Zealand

  12. Börje Blomquist

    Hello I am interested in price of the coil for heating outdoor tub
    Mvh Börje Blomquist

  13. Eric

    Price for
    Heater Coil only (Type A Option 1A);

  14. Eric

    hello how much for Type A Option 1A&1B:
    Heater Coil only (Type A Option 1A);

  15. William Astrande

    I want to order

  16. P meredith

    Can the coil be used to heat a radiator,with the use of a pump,thanks

  17. Egon Gfrerer

    Hello, Please supply pricing for Type B Option X : Coil + valve + extended rubber hose + attached flange = Add on kit – Roast grill. Plus shipping to Queensland Australia. Thanks

  18. Christo

    Hi, can you please tell me what prise is for this stainless steel coil for dutch tub

  19. chen liky

    hello,I want a heater coil to heat my tub in wild.

  20. Justin

    Hello, Im interested in the type A option 1A for purchase. Where can I order this and how much is it? United States, Oklahoma. Thanks.

  21. Brian

    looking for coil only

  22. Karin L. Larson

    I want to DIY a wood fired hot tub and I need your heater coil.The kit must include all parts: coil,stand,fire holder and wind smoke guard.My tub is going to hold 300gallon water.Need the kit ship to New York with freight.Please suggest.

  23. Ian Bester

    Please supply pricing of heater coil and its components plus shipping to South Africa

  24. Adam Millstine

    hello how much for Type A Option 1A&1B:
    Heater Coil only (Type A Option 1A);

  25. Scott

    Hi How much for this package shipped to 10987 in USA. Heater coil + Flexible extending hose + Attached flange valve, fire holder; ground stand and wind screen. I have a large tub so if you could make this with 10 or 11 circles that would be good. Thanks

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