How to Build a Wood-Fired Hot Tub (2024)

FAQs

What is the best wood for a wood fired hot tub? ›

Based on this criteria, we recommend dry birch wood which yields the best results. As a rule, the drier the wood, the better. It is also recommended to split every log into several smaller pieces for a greater surface of contact with the fire and thus faster heating.

Always pay close attention to water hygiene when using lake or seawater and if you have any suspicions regarding the cleanliness, you should change the water and clean the hot tub. It is recommended to change the water every one or two days after normal family use.

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.

Treating with Oxygen is better for the tub than Chlorine or Bromine as the wood is an organic material and will become damaged with an overuse of these products.

A wood fired hot tub can take up to three or four hours to heat the water temperature to 105° F, depending on the water capacity and heating method. A smaller ~350 gallon tub may take as little as 90 minutes to heat, whereas a larger tub fit for five or six people may take three to four hours to heat.

Our tubs are made from spruce (average life 10 years) or larch (average life 20+ years) high quality woods known for their longevity. There are a few things you can do to help prolong the life of your tub. For instance we recommend a coat of protective oil on at least an annual basis.

Ideally you should change the water in your hot tub after every use; however you can use it several times across a couple of days, this is more to personal taste. If you're going to leave the tub for a time, you should drain, rinse and refill the tub prior.

Sanitizing Your Hot Tub With Chemicals

You can always add non-toxic chemicals to sustain the longevity of your water. We recommend granulated bromine and hydrogen peroxide because they're gentle and effective at safely sanitizing your water.

Our top tips

It usually takes 3-4 hours to heat the water up to the correct temperature, which is around 38°C. Keep checking the fire. If you leave it and disappear for a few hours, the fire will die, and you'll be left staring at a giant water pail. Keep the lid on the hot tub – you have saucepans at home, right?

Wood-fired hot tub means better operating costs, considerably quicker heating, and it's a more sustainable option today that can be placed in your back garden, next to a woodland cabin holiday let, or just anywhere else you want.

How do you waterproof a wooden hot tub? ›

We recommend using vinylester resin because it is especially suitable for hot tubs. In addition, vinylester is resistant to hot water and chemicals such as acids and chlorine.

Maintaining a wood-fired hot tub can be more labor-intensive compared to other types of hot tubs. The wood-fired system requires regular cleaning and ash removal. Additionally, the water in a wood-fired tub needs to be changed more frequently to prevent the growth of bacteria and algae.

You can help expedite your wood fired hot tubs heat time by placing insulation beneath the hot tub, wrapping it around the foundation of the tub before placing the cedar cladding around it, and keeping the rigid insulation below the cedar lid while it's heating and between uses.

As a general rule of thumb, don't allow a hot tub full of water to freeze solid. It's a hassle to melt that much ice. If you're not going to use your wood fired hot tub for an extended period during the winter we recommend draining and turning the tub on its side.

A wood fired hot tub is an efficient and simple soaking tub which uses a wood burning stove instead of an electrical heater. They tend to have a circular barrel shape made of cedar wood. Due to the wood burning stove, the hot tub heats up significantly faster than a regular electric heater.

The Low Heat Problem

Some quick remedies to get the sauna to the required temperature include: Use small chopped wood and ensure the stove is well-ventilated for sufficient airflow. Adjust the stove appropriately. Ensure that the wood is dry and well-seasoned.

Because wood-fired tubs heat up 5 times faster than electric-heated ones, you may wonder how much it would cost to run them. Since wood-fired tubs only require dry firewood to function and use no cords or electricity, wood-fired will always be more cost-effective as firewood is much more affordable than electricity.