FINNTub Nordic is our hot tub in plastic with an efficient external (25 kW), wood-burning stove. The heater is made of double-walled marine aluminum, which quickly reaches the correct operating temperature, which is important to minimize deposits on the interior walls of the stove. It is also important in view of the smoke and combustion efficiency for a cleaner environment. Since the stove is placed on the outside, it doesn't occupy any space inside the hot tub which then can be fully used for the purpose it's intended.
Our City- series of hot tubs with a 24kW gas heater, City-Tub, is a convenient solution for those who live in urban areas and want an affordable hot tub with rapid heating. With gas for heating your hot tub you avoid smoke and the additional work that is involved in burning wood. So you can bathe in peace and your neighbors will not complain about the smoke a wood-fired hot tub can cause.
In general it can be said about all plastics, that it is the material thickness and the design that determines the stability. Thinner materials provide savings in manufacturing costs, but is negative for the durability of the product.