Northern Lights is a world leader in manufacturing wood fired hot tubs. As with all our hot tubs, we use 100% clear western red cedar. Wood burning hot tubs are popular among those that prefer the combination of a wood hot tub and a wood stove for the ultimate in hot tub soaking experience.
Most wood fired hot tubs are used in rural locations that have access to plenty of wood. This certainly reduces the operational costs of using a hot tub! The wood burning hot tub uses no electricity, and thus there is no forced circulation system – like what you’d find on our other jetted hot tubs. Instead, the natural principal of thermosiphon is used.
Northern Lights is a world leader in manufacturing wood fired hot tubs. As with all our hot tubs, we use 100% clear western red cedar. Wood burning hot tubs are popular among those that prefer the combination of a wood hot tub and a wood stove for the ultimate in hot tub soaking experience.
An internal heater consumes nearly 1/3 of the internal space, requiring a much larger hot tub to fit the same number of people as an external heater.
A hot tub loses nearly half of its heat from the top as hot water rises. With an internal submersible heater, it is impossible to use a fully insulated cover and retain that heat. With a fully insulated cover for your wood fired hot tub, you can leave the tub in the evening – and enjoy hot tub-ready water temperature in the morning, without restarting the fire.
With a submersible hot tub heater, the water level must be maintained within inches to protect the water heater from being exposed and melting. The problem arises when bathers overflow the hot tub (which can happen often if you’re entertaining). Then, before the last person or people leave the cedar hot tub, more water is required to be added – so that your water level is brought back to the operational level. This usually means getting out the hose, and adding cold water while bathers remain in the hot tub until this process is finished. Not a great way to end your soak!
An external hot tub heater has the chimney away from the wood fired spa, so there is no chance of contact with a hot chimney. With an internal wood hot tub heater, the chimney is within inches of the bathers – and there is more chance that smoke and sparks fall directly back to the bathers in the wood fired hot tub.
Fueling your wood fired hot tub from outside means less debris ends up in the hot tub! Loading wood directly over the hot tub water inevitably causes wood and ashes to land in the water – requiring frequent cleaning. By controlling the fire away from the hot tub, there is no debris that ends up inside the wood burning hot tub.
Most internal heaters have a fencing system, and a heater mounted to the floor. This makes cleaning the wood fired hot tub very difficult in the heater region. In some cases you need to fully disassemble protective fence to access the floor area that can often trap leaves, grass, and sand.
A wood fired hot tub is normally used differently than a regular electric or gas fired hot tub. With a wood burning hot tub, the users typically fill the hot tub, use it a couple times – then drain the water. With this type of short term use, there is no need for chemicals – which is a great advantage to those that want a pure chemical free hot tub experience.
Like any wooden hot tub, the exterior should be stained if the customer wishes to keep the rich cedar colour. If left unstained, the hot tub will eventually turn to a natural grey color.
Our wood burning hot tubs also have the option of adding a pump filtering system with 4 jets. The optional upgrade is available in a 110-120 VAC power source that can plug into a home outlet that has a GFIC protected plug. With this option, customers get the added use of hydrotherapy massage jets. The other reason customers often add this option is that it will filter the water. This means they can maintain the water clarity without having to frequently drain the tub. By adding a filter system, a customer can reuse the water for months without having to drain it. If you are planning to use a wood fired hot tub in a vacation home or on weekends, you can enjoy your hot tub experience a lot quicker with this option – as you won't have to fill the hot tub on every visit!
The essential difference (from a water-heating standpoint) is that a wood fired hot tub heater cannot keep your hot tub's water at an exact temperature, as the other heating options can. The heat will also tend to stratify – meaning that the hottest water will rise to the top, while the cooler water will sink to the bottom. To combat this, you can easily use a paddle or similar tool to stir the water occasionally while you soak. The optional filter option will help reduce the stratification by force mixing the water.
Controlling the temperature and heating times will depend on the type of wood, the water temperature, and external outdoor temperature. However, by using the same type of wood, a user will quickly get the feel for the right amount of wood quantity – and the heating time required to reach the optimal water temperature. It is important to mix the water in order to get an accurate water temperature before you enjoy your hot tub – as the top may be hot, but the bottom might still only be warm.
The heat up time of a wood fired hot tub will depend on the water volume and the size of wood fired hot tub stove that is used. This chart below is an approximation based on a Timberline Wood Water Stove. For most hot tubs a Medium "Blaze" size stove is recommended (55,000 BTU) for our smaller Ofuro Japanese Hot Tubs a smaller "Camp Fire" Model (30,000 BTU) is recommended.
When starting a fire in the stove, it's best to use clean-burning paper for the initial ignition. Follow that with dry kindling overlaid with criss-crossed logs. Initially, the air flow should be open to MAX in order to get the most air into the fire. The rule of thumb here is simple: the more wood you use, the faster the water in your hot tub will get to soaking temperatures (about 104ºF). The more wood you add, the longer the water will remain at the proper temperature. If the water gets too hot, damper the fire using the chimney damper, and reduce the airflow into the stove – both of which will cool things down pretty quickly!
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