Quick Answer
Yes, you can use scrap wood for heating water, but the wood must be dry and free of chemicals to avoid contamination. The burning efficiency and water temperature will also depend on the wood's density and moisture content.
Choosing the Right Scrap Wood
When selecting scrap wood for heating water, look for dry hardwoods like oak, maple, or ash, as they tend to burn more efficiently and produce less smoke. Hardwoods have a higher energy density than softwoods, which means they release more heat per pound burned. Avoid using pressure-treated or painted wood, as these can contain chemicals that may contaminate the water.
Preparing the Wood for Burning
To prepare the wood for burning, split it into manageable pieces to increase the surface area. This will help the wood dry faster and burn more efficiently. Aim for a moisture content of 20% or less to ensure optimal burning performance. You can use a wood moisture meter to check the wood’s moisture level.
Building a Wood-Fired Water Heater
To build a simple wood-fired water heater, you’ll need a large metal drum or tank, a wood-burning stove or furnace, and a heat exchanger to transfer the heat from the burning wood to the water. Drill holes in the bottom of the drum for the water to flow in and out, and attach a heat exchanger to the side of the drum. Add a chimney and a flue to vent the combustion gases safely. Fill the drum with water and light the stove to heat the water.
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