Nothing is better than having a hot tub in your backyard to enjoy after a stressful week. But what if you don’t want to get those new inflatable models that everyone has but rather have something cozier and much better-looking? Well, then wood-fired hot tubs are the ideal solution for you since they are aesthetically pleasing, heat up fast, and don’t require electricity to work. In this article, we will learn how to build a wood-fired hot tub and see which are the two most common design options out there.

If you’re looking for something slightly more portable and easy to set up, I suggest checking out my guide on some of the best inflatable hot tubs for this year. Now, let’s start by discussing the different kinds of hot tubs you can make that are all wood-fired…

Types of Wood-Fired Hot Tubs

While it is hard to classify a DIY project since everyone will eventually build it by his/her taste, we will cover the two most common types of DIY hot tubs out there. Those are:

  • Hot tubs with galvanized stock tanks
  • Traditional wooden hot tubs with a submersible wood stove (or an external one)

While both of these are semi-hard to build, the tubs using a galvanized stock tank and an external wood-burning stove are by far the easiest and common method among DIYers.

Let’s go through each of those now and see which one is more suitable for your needs and resources…

Converting a Galvanized Stock Tank into a Hot Tub

The first thing we need to do here is listing the materials that we are going to be using:

  • A 200-gallon stock tank (preferable sizes 6 by 2 by 2 feet)
  • Gravel
  • Concrete
  • Sand
  • Copper tubing (1/2 inch around 20 feet)
  • A bucket
  • 1 x 1/4 inch steel bars
  • Hole saw
  • Tank fittings (plastic)
  • Silicone
  • Compression fittings

Start by getting your stock tank and figure out a place for it in your background. Depending on your size or how many people you want to fit inside, you might want to get a bigger or smaller tank. Typically, anything around 200 gallons works perfectly for one person or two kids. Since you also don’t want the tank to sink into the ground, you can’t just put it on top of any patch of soil in your yard. To prevent sinking, you will have to create concrete footings. Dig up a hole with the approximate dimensions of the tank and pack some gravel inside. Above that, pour two square-shaped footings. After they dry up, add more gravel on top to level the whole thing and some sand to further smooth things out. Now that this is done, you can put your tank on top without worrying it can sink. or move around too much. The edges of the tank will hook right into the top layer of sand and it will stay there for good.

Next up, you want to get some copper tubing (half an inch). Make sure it is around 20-30 feet, depending on the size of the coil that you want to make. Wrap the tubing around a 4-7 gallon bucket so that it is around 20-25 inches in height when coiled and put upwards. The spacing between the tubing is not important to be perfect but make sure it is at least symmetrical. For added rigidity, you can use steel bars that bolt the coil into place. That steel bar will, later on, be handy when you have to fix the coil to the ground next to the tub. Use a hole saw to drill holes into the tank (ideal size would be 1 and 3/8 inch in diameter for this tubing). Make sure those holes are as much apart as the distance of your coil’s height. For example, if your coil is 20 inches, make sure the holes are exactly 20 inches apart. If your tub isn’t that high, adjust the height of the coil and the distance between the holes.

Use tank fittings to put through the holes and seal them with water-resistant silicone. Screw in the compression fittings which will take both ends of the copper coil. Once that is done, you can put the coil into the sand. Use as many more steel support bars as you think is necessary to keep the coil stable. Once that is done, it is time to start the fire inside it. Build your fire until its hot enough and test whether hot water is flowing from the upper tube.

Additionally, to make your project complete, you can build a lid that will keep all the heat inside while you’re warming the water. That will make the tub more efficient and will actually allow it to fully heat up quicker. Use 3/4 thick hardwood pieces and stitch them one to another any way you find the easiest. Bonus points if you make the lid follow the curve of the stock tank.

This setup will allow the water to easily go up to 110 degrees (Fahrenheit) and once you get to that temperature, try spreading the wood in the copper coil outwards so that only the coals are left inside. This will maintain the temperature in the 100-110 range for enough time for you to enjoy your newly made hot tub!

Click here if you want to learn more about the process of cleaning and maintaining hot tubs! Now, the next way we’re going to cover is going to be a lot more complicated and you will most likely need some help in the process…

Building a Wood-Fired Hot Tub From The Ground Up

Making your own wooden hot tub and then adding the stove either in it or next to it is a bit more complicated. The first thing that you have to decide is what wood you will be using. The most durable and common choice is, of course, cedar but other wood types work too. The process requires a lot of sawing, milling, jointing, and more which is all done by a plethora of power tools so make sure you have all the needed equipment before you start such a project.

The second thing that you have to decide here is whether you will submerge the stove into the tub or have it outside. Now, there are quite a few benefits of having it inside your tub but also a few obvious drawbacks. It will eat off your internal hot tub space and will also pose a risk of overheating the water or you touching it with your legs. External stoves will heat up the water significantly slower but are safer and won’t compromise your hot tub’s internal volume.

Since the process is far more complicated than the one with the stock tank, I suggest watching this full video where all the steps are described in great detail! The tub there is submersible

Wood-Fired Hot Tub Benefits

Now that we’ve discussed how you can make one, let’s go through some of the major benefits that you will get by owning such a hot tub:

  • These hot tubs don’t require any energy source to heat up, allowing you to have them virtually anywhere you want. They can be installed in your backyard, at your cabin in the woods or summer house by the lake.
  • The time to heat up with these tubs is significantly reduced compared to the inflatable tubs that often take more than a day to get to the desired temperature.
  • You can choose the design and dimensions of this tub, making it fit as many people as you planned for.
  • You get to enjoy all of the health benefits of a hot tub while out in nature with a stove burning next to you which adds to the relaxation.

If you want to further understand how a hot tub helps your body heal up and regenerate, make sure you check our article on hot tub health benefits.

Frequently Asked Questions

How long does a wood-fired hot tub take to fully heat up?

Typically, a normal-sized wood-burning stove will bring the hot tub to its maximum temperature in around 3 hours. This process still depends heavily on the outside temperature, the size of the hot tub, and the capacity of the stove. I suggest starting the heating up process when the water level inside the tub is at around 80% capacity.

Are wood-fired how tubs any good?

Yes, they are! One of the biggest advantages is that they require no external power source and can be built in practically any location. They save money, give the great scent of burning wood, and are far more relaxing than electrical ones.

How to prevent my pipes from freezing in the winter?

The best way to winterize your hot tub is by putting antifreeze in the system once you’ve stopped using it. The most important thing is to not let anyone use it after you’ve put the antifreeze. If you want to use it again, you will have to drain it all out, clean the pipes, and re-fill it with water.

Can you use Epsom salt in your hot tub?

This isn’t generally a good idea since you can damage the hot tub and if the water is chlorinated you can also cause some harm to your skin. If you’re set on using it, though, make sure that you clean the hot tub thoroughly after you’re done using it.

Final Words

Now that you know how to build a wood-fired hot tub, all that is left for you to do is roll up your sleeves and get on with it! Choose wisely between the stock tank option and the wooden (cedar) one, since both have their advantages and disadvantages and it all ultimately boils down to you (pun intended).