Aluminum PEX pipes have many uses. They can be used as normal plumbing pipes, in radiant heating, in refrigeration, air-conditioning, distribution of hot & cold water etc. One of the lesser known uses of aluminum PEX pipes is in wooden furnaces. When it comes to wooden furnaces, both standard PEX pipes as well as the aluminum versions can be used. Other options for wooden furnaces include copper pipes & CPVC. Copper pipes are expensive & CPVC is pretty hard to install. So the more realistic options are either PEX pipes or PEX-AL-PEX pipes.
It is always better to use PEX pipes for wooden furnaces instead of regular PEX pipes. One of the reasons why this pipe should be used in wooden furnaces is its flexibility. Use of aluminum makes the pipes really strong & when one bends it in a shape, the pipes maintain that shape. The curves that gets created by bending the pipes eliminates the need for elbows & thus, reduces the friction that gushing water creates. This friction can be harmful for the durability of a pipe. Since no elbows are needed in the aluminum pipes, it works for a longer time.
Outdoor wood furnaces would mean the use of a lot of hot water & that hot water would pass through the pipes. It is simple physics that when a substance comes in contact with high temperature expands its size. The expansion rate of PEX-AL-PEX is minimal. In fact, the expansion rate of aluminum PEXs is same as copper pipes. So if you are using PEX-Al-PEX pipes for your outdoor wooden furnace, you do not need to worry about expansion rate of the pipe since it is minimal & won’t cause you any problem in the future. The lines more or less maintain their shape & do not exert any extra pressure on the fittings or the pumps.
Performance of aluminum PEX pipes while transferring hot water is also much better than any other types of pipes including regular PEX. This is extremely important for the heat exchangers for the performance of the heat exchangers that are used in outdoor wood furnaces. One inch inside diameter of PEX-AL-PEX pipes helps in transferring hot water in a much lesser time compared to the heat exchange systems.
