How to heat up your hot tub quickly and easily | Kirami heaters
How to heat up your hot tub quickly and easily | Kirami heaters 

Q: What kind of wood should I use?

A:  The best and most cost-efficient type of wood is dry, chopped birch (Nordic countries). When burning hardwood, always use a separate ash box made of stainless steel. Of course, other wood species and types can be used as well. Generally speaking, the higher the density of the wood, the better the heating value, and the most essential factor is the dryness of the firewood. 

Q: How much wood do I need for heating the hot tub?

A: Depending on the time of year, heating the hot tub takes 60–120 litres of dry birch firewood (Nordic countries).

The amount of firewood needed varies depending on factors such as the starting temperature of the water, the moisture content and quality of the wood, and the outside temperature. Below are estimates of how many loads of firewood each heater model consumes.

Cult: approx. 7–10 loads

Macu: approx. 6–9 loads

Cube: approx. 5–8 loads

Tube: approx. 4–7 loads 

Q: What should I take into account when heating the hot tub?

A: First of all, make sure that there is water in the tub! Even if you have heated the tub the night before, check the state of the tub anyway. If you want to heat the water as quickly as possible, use dry and high-quality firewood. Using a tub cover shortens the heating time significantly. Empty the heater of ashes before heating, including the top of the grates. Maintain a large fire and add firewood once every 10–15 minutes to make sure that the fire does not go out in the middle of the heating process. The water is circulated by the force of gravity, meaning that if the fire goes out, the circulation slows down and it takes time to restart the fire and restore the circulation. 

Kirami Mixing paddle is used for mixing the water at the heating stage, to even out the layered temperature | Kirami
Kirami Mixing paddle is used for mixing the water at the heating stage, to even out the layered temperature.

Q: How is the water heated?

A: The bathwater is heated with a wood-burning heater supplied with the hot tub, so no electricity is needed. When heated, the heater must be full of water, meaning that the water level of the tub must be above the upper lead-through. When heated, the water becomes lighter in weight, whereby it rises to the upper part of the heater and is transferred into the tub through the circulation pipe. Cold water in the tub descends to the bottom and is transferred into the heater through the lower circulation pipe. 


Q: How quickly can the bathwater be heated?

A: The heating rate of the bathwater depends on the power of the heater, the size of the tub, the quality of the firewood, the air temperature and whether or not you use a tub cover. For example, in a 0 °C temperature, a 1,450-litre tub will take approximately 2–3 hours to heat.For heating, we recommend using dry wood chopped into small pieces. Using large and moist firewood may even double the heating time. 


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Hot tub heating | Kirami
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