Wood Fired Hot Tubs FAQ Handbook

Relax, rejuvenate & restore in a classic way

The perfect addition to your residential property, short-term rental, cabin, bach or any other secondary residence. Relax in hot water, listening to a crackling fire in one of Cedar Spring Recreation’s Wood Burning Cedar Hot Tub, also known as Japanese Soaking Tubs. These traditional, cooperage–style cedar hot tubs are hand-crafted from our self sourced 100% Canadian Grad-A clear western red cedar, giving you quality and craftsmanship that stands the test of time. Using no electricity, this uniquely designed wood-burning hot tub heater takes about 2-3 hours to heat your tub water from 7.2° C to 40.6° C. Filtration and chemicals are not necessarily required as you will change the water frequently.

Why purchase a wooden hot tub?

Because they’re simple, beautiful, low impact to your property and can add a tremendous amount of perceived value to any property. Ongoing costs, compared to traditional spa pool, are a fraction of the price (each time you heat your tub costs $4-5 worth of wood… if you don’t have your own supply!). 

How big are the hot tubs?

We sell hot tubs for almost any size, small enough for a romantic dip, or big enough for a football or netball team! Our best-selling model is made for up to six people, but we sell a range of models. Take a look at our full selection or reach out if you’d like us to look at making something bigger!

When can I use my wooden hot tub?

You can use your wooden hot tub all year round. It can also be used with hot or cold water. This means you can use it as a refreshing pool in the hot summer months, and as a relaxing hot tub in the cold winter months. We also recommend you combine your hot tub with one of our wooden saunas, there really is nothing like going back and forth between a hot tub and a sauna – it is the peak of relaxation. Both of which are great for contrast therapy (hot/cold therapy).

How long will my wooden hot tub last? How do I make it last longer?

Your wooden hot tub should last at least 30 years. Treating the hot tub semi-annually (1-2 times per year) with linseed oil (externally only) and a wood protection agent, and cleaning the inside of the hot tub with non-caustic soap using a brush or high-pressure cleaner will extend the hot tub’s life expectancy by a further 10-15 years. Do not paint the hot tub, or treat the inside of the wooden hot tub. You do not have to clean or treat the underside of your wooden hot tub, as the hot tub is designed so that dampness on the hot tub bottom does not occur.

Where can I put my wooden hot tub?

Your wooden hot tub must be placed on stable, flat ground. We recommend placing the wooden hot tub on a gravel, wood chip, or stone / concrete tile base. We do not recommend placing the wooden hot tub directly on dirt or grass. Depending on local conditions, a drainage system could be recommended. 

What is my wooden hot tub made of?

Your beautiful new wooden hot tub is made out of our self sourced Canadian red cedar. This is the absolute best for this application. It is strong, elastic, and durable. It is highly warp-resistant, and one of the longest-lasting woods. Additionally, red cedar has a beautiful appearance that we know you and your guests will appreciate.

Does my wooden hot tub come fully assembled?

No! However, we are a local company and can work with you to find someone locally to put it together for you — just give us a call to talk about that! That said, our hot tubs are easily assembled by matching the wood components together using the “tongue and groove” principle. Standard tools and a little bit of time are required. One requirement of self-assembly, however, is that you take no longer than seven days to fully assemble your wooden hot tub. After this time, the natural wood may warp if not fully assembled. Contact customer service if you have any questions or concerns, we are available 6 days a week. 

Are there any special set-up instructions?

Yes, there is a specific method when filling your new wooden hot tub for the first time.

First, fill the water (usually with a hose) until it reaches the 10 cm mark. Leave the hot tub like this overnight. This will allow the wood to swell and make the hot tub walls and floor dense and consistent.

Continue this process each day until the hot tub is at 80% capacity. Each day, add four inches of 10 cm and let it sit overnight. This will allow the wood to swell and help extend the life of your wooden hot tub.

How do I operate my wooden hot tub?

After the initial filling process (outlined above), filling your wooden hot tub becomes faster and easier. Simply fill the hot tub with your garden hose to 80% of the hot tub capacity. You may also use water sourced from a lake, a river, or the ocean. Make sure to cover the stove surface by at least 1.5 inches when the heater is installed inside the hot tub. And remember to never heat the hot tub when it is empty. This can cause a fire and/or irreparable damages.

  • Caution: Do not empty the hot tub until the stove has completely cooled down.

 What about the cold winters?

Our hot tubs are designed for the rugged Canadian winters which means they are more than designed for the colder Alpine temperatures in Australia and New Zealand. How you deal with a wood-fired hot tub in very cold weather depends on your usage pattern and whether or not electricity is available. If you are using it at least once a week you should be fine in all except the most extreme weather as the water (with appropriate covers) shouldn't lose more than about 15-18 degrees per day in all except the most extreme weather. You do, however, want to avoid having the entire tub freeze solid as that will most likely damage the bottom boards.

If you will be leaving your tub untended for extended periods of time in sub-freezing weather, here are some things you can do to prevent damage to the tub from freezing:

  • If you have electricity, a stock tank heater is the most simple, inexpensive and effective solution to keep the tub from freezing.
  • If water availability is not an issue, drain all but 4-5 inches or so and just let that freeze and refill when you return. The few inches of ice won't hurt the tub and will help keep the tub bottom and base of the staves (the walls of the tub) "seasoned". When you are ready to use the tub simply top it off and fire up the stove.
  • If water to refill the tub is an issue you can anchor 8-10 floating empty plastic milk jugs at varying levels in the tub. When the water freezes and expands the milk jugs will act as shock absorbers so the tub isn't damaged. This approach is most useful when water to refill the tub is a problem.
  • If you do not drain the tub and notice a few inches of ice on the tub surface, just start up a small fire, and let the stove heat slowly. You can allow several inches of ice to form on the surface of the tub without doing any damage.
  • If the tub does happen to freeze completely, caution is advised. You can melt the ice by starting a fire, but a fast-burning fire quickly melts the ice around the stove. The water can then boil away exposing the stove to air which will cause the aluminum to melt. Without water surrounding the stove it could melt. We recommend adding some water to the top of the frozen surface while melting the ice. You should try and heat your tub up at least once a week, and of course, heating it up means you get to enjoy it, too.
  • Some owners with tubs at cabins where there is no water available during winter months leave their tubs full, but secure with a rope a large, partially inflated inner tube to the bottom of the tub. This allows the inner tube to take the stress of the expanding ice so that the tub is not damaged. (The inner tube needs to be completely submerged near or at the bottom of the tub).

What can I add to the hot tub water?

You may add any natural and biodegradable product you wish to the water for relaxation purposes. You can add salt, herbal extracts, or essential oils to heighten your wooden hot tub experience. Adding non-biodegradable products to the water could cause bacterial/algae growth.

How long does the water take to heat up?

This depends. Our hot tubs come in many sizes (ranging from 2-8 person capacity), so naturally the heating time depends on the size of the hot tub. Heating time also depends on the external temperature, the wind conditions, and whether the hot tub has been covered (insulated). Generally, heating time ranges from 1.5-4 hours.

How do I manage the ash from the oven?

How often you clean out the ash depends on how often you use your wooden hot tub. For infrequent users, once a month should suffice; for frequent users, we recommend clearing out the ash once a week. Use a shovel to remove the ash. For best results, use the specially designed ash-removal shovel available on our website under “accessories”.

How do I drain the wooden hot tub?

The wooden hot tub has a drainage valve. Simply connect a hose to the valve and release the water. It is not necessary to change the water each time you use your wooden hot tub. Change the water only when necessary.

How do I manage water cleanliness?

Watch out for algae growth, or a greasy film. This is a sure-fire sign your water needs changing. You may use a UV-purification system, though chlorinated supplements are not recommended (these may degrade the wood).

My new wooden hot tub is leaking? What’s going on!?

Relax! This is totally normal. Because wood is a natural product, each piece has its own intricacies and features. Eventually, the wood will swell and settle and you will no longer experience leaks.

How long can I leave my wooden hot tub empty?

You should not let your wooden hot tub sit empty for an extended period of time. This can cause the hot tub to dry out, and can cause warping, affecting the hot tub’s density and consistency. If your wooden hot tub does sit empty for a long time and the tension straps fall down, follow these instructions:

  • Using short screws to avoid damaging the stave or the wall, screw four screws underneath the tension straps into the wood.
  • If the tension straps are very loose, you should tighten them carefully until the staves are even and fixed to the floor section.
  • Fill the hot tub with 5-10 cm of water so that the hot tub floor can become consistent again.
  • Please note that the tension straps must be loosened gradually over time. If the straps are kept too tight, the hot tub will not become dense and consistent.

I left my wooden hot tub empty for a long time, and now it leaks. Do I tighten the tension straps?

Not under normal circumstances. The tension straps are made so they do not have to be tightened. The dry wood absorbs the water, swells, and becomes dense and consistent.

My wooden hot tub is sitting empty. Should I cover it?

No, you should not. Air needs to circulate in the hot tub to prevent the formation of mould.

Is my wooden hot tub portable?

Yes it is. If you are redesigning your yard or landscaping, you may carry, roll, or lift your wooden hot tub to a different location, depending on its weight.

Our wooden hot tubs range from 4.5 feet (130 cm) in diameter up to 8.5 feet (250 cm). Each wooden hot tub has a height of about 3.3 feet (100 cm).

General Warnings:

  • Fire and hot water can cause injuries. Do not leave children unattended around the wooden hot tub.
  • Please do not use the wooden hot tub when under the influence of prescription medication, alcohol, or recreational drugs.
  • Do not leave the hot tub unattended when the stove is burning.

General Information:

  • Please note that all information included here is based on best practices. 
  • However, local conditions and other factors must be taken into account to ensure a successful experience for each individual wooden hot tub user. 
  • It is important that you do your own research about wood fired appliances, such as hot tubs, and the requirements or local bylaws and regulations that might be in place. 



Your tub will seal itself and achieve a watertight seal through the natural swelling of the wood that occurs as water is absorbed into the wood.

Begin to fill your tub with water using a standard garden hose. If your water supply is limited, see tip#4 in the following section on leaks. Once the tub has begun to hold water, you can expect some dripping and leaking. If you have done a superior job it may hardly leak at all. If your tub is not as tight as some it may leak more.

Don't get nervous if you see small streams of water. As long as you have closed your gaps to less than the thickness of a matchbook cover and there aren't more than a half dozen or so such gaps between the staves, the tub will be able to swell and seal itself. If your tub is holding water above the minimum water level of the stove, and you plan on keeping a careful eye on the water level, you can start a small fire and heat your tub up a bit. The warm water helps the wood swell. Don't let the water drop below the minimum water level on the stove. The swelling and sealing process may take three days to one and a half weeks to run its course. Cold winter weather can cause the swelling process to take longer. Occasionally, a tub may even drain completely after the initial filling, but the wood is absorbing water and swelling so keep adding water. 



At first, tannins from the wood will leach into the water turning it reddish brown. This leaching process may last anywhere from 2 - 3 months depending on the amount of tannin contained in the wood. The tannins are not harmful and in fact are indicative of the amount of natural preservative in the wood, but they can discolor bathing suits. The discoloration of the water can be controlled with chlorine and related standard spa chemicals.

Because the tannins leach out quickly at first, you will find that you have to replenish the chlorine fairly often in order to keep the water clear, but this should decrease noticeably after a few weeks. As always when adding chlorine to a tub, dissolve it in water in a bucket first.



Additional FAQ

Q: How much does it weigh?
A: The entire shipping weight of a 6' x 4' kit is approx. 306 kgs including crate. The tub minus the stove and benches can be easily carried by 4 people.

Q: How many litres does it hold?
A: 6' x 4' tub holds 2270 litres.

Q: How do you control the temperature?
A: Start out with a roaring fire until you get close to temperature, say 35C, then reduce the size of the fire until it reaches 38C-40C+. When you get to tub temperature keep a small fire going. The fire can also be slowed down by adjusting the draft. 

  • It is better to control temperature by fire size than by closing the damper because a build of up creosote can result. 
  • It is also easy to cool down the tub just by adding cold water.

Q: How long does it take to heat up?
A: It takes  3 1/2 to 4 hours to go from 7C to tub temperature 38C. This is four times as fast as a conventional spa heater. 

Q: How much wood does it take?
A: A moderate size wheelbarrow load of DRY wood.

Q Can we use salt water?
A: Yes. The stove is made of salt water certified aluminum, and all hardware included with the tub is non-corrosive. The cedar is not affected by the salt.

Q: Does the tub come with a warranty?
A: Your total satisfaction is our goal. The stoves have a 1 year warranty.