The natural operation of a hot tub heater

Construction external hot tub heater

First, I am going to explain as clearly as possible the construction of an external hot tub heater. The stove actually consists of two parts. The inner part of the stove and the casing. The inner part of the stove is the fire chamber. This is the space where you can put the wood and start the fire. In addition, the inner part also contains the ash pan and the smoke shaft. This inner part of the stove is enveloped by the outer casing. Between the outer casing and the inner part of the stove is the space for the water.

The inner part of the external hot tub heater is surrounded by water on almost every side. By stoking a fire in the fire chamber, the heat is transferred to the water through the aluminum walls of the inner chamber. Therefore, you will always notice that the outside of the external heater does not get very warm at all. This is because there is water between these two parts, and the outer part is never in direct contact with the fire. Be careful though, the stove tube does get very hot!

Traditional hot tub

In a traditional hot tub, you will find that the hot tub heater is always at the same level as the bottom of the hot tub. This is necessary, because heating a hot tub uses a natural phenomenon. The heater is equipped with two passages, where the water can go in and out.

Due to the natural property of water, heated water will want to rise. Therefore, the water being heated in the hot tub heater will exit the heater through the top passage. This natural phenomenon creates a natural circulation. The warm water will rise allowing new colder water to flow into the stove at the bottom. In this way, the external heater can heat your entire bath, without the use of electricity.

Unfortunately, when you do not choose a traditional installation of a hot tub, for example in built-in projects, this natural phenomenon cannot be generated. This is because when the hot tub heater receives too much resistance from the water, the hot water will not be able to escape. In such cases, we use a circulation pump.

Want to know more about firing and building an optimal fire in your hot tub stove? Then take a quick look at our video On firing a hot tub stove.