Best Wood for Heating a Pool or Hot Tub
Wood comes in many different shapes and sizes, but all wood starts of as a living organism that requires water and sunlight to grow. When harvesting wood all wood will be considered “green”. Green wood is the called this because the inside will have a greenish color resulting from the water and the chlorophyll found in the fibers. In order to properly burn wood, you must first remove the water and “season” or age the wood. Wet wood burns very poorly as the water in the wood stops counteracts the flame and results in a terribly slow burn with little energy. Wet wood will also smoke heavily and can be an annoyance when using your pool or hot tub.
To season the wood you can either buy it from a source that has already let the wood age and the water in the wood has evaporated. If you choose to harvest and season the wood yourself, you should ensure the wood is first cut into useable sizes. For our stoves, an 18” log is ideal. The logs then get stacked outdoors in an area that allow them to breathe naturally. A wood shed is ideal as the shed typically has a roof but has open walls that allow wind to pass through and remove the moisture. The roof protects the wood from rain while still allowing the wood to breath. It typically takes one full year to season the wood. In some cases, even longer. If you spilt the wood into pieces first, you will greatly decrease the amount of time required to season the wood.
Hardwood is best! When choosing the type of wood to use in your wood burning pool heater we recommend hard woods be used over softwood. However, softwood such as cedar or pine are great wood to start a fire with as they typically are rich in oils that burn quickly. The problem with soft wood is the burn quickly and will require more management of the fire. A hard wood has much denser fibers and as such will burn for a longer time. You can feel the difference between a hard wood and softwood simply by the weight a log will have (assuming it has been properly dried).
Getting the fire going in the beginning is important as this will be the foundation for burning the logs, smaller timbers split up work best and will burn fast to create a bed of coals. Once the coals are present the heat energy will then allow larger hard wood logs to burn.
In Summery the most important part of a good wood is properly dried and seasoned wood, your other choice is to choose hardwoods such as birch or oak for a longer lasting fire. Never use coal in your wood fired pool heater as coal can get too hot and could damage the internal fire box. Start off with a small fire and then add larger split logs after the base has been created.