Thursday, February 2, 2012

DIY Wood-Fired Water Heater

by Mark Crush

This is a cheap wood burning water heater; great for missionary work or a remote cabin, backwoods lodge or camp.

Here is what you will need to build your own wood-fired water heater:

  • Gas water heater new or used, with all of the gas lines, burner assembly etc. removed from the bottom. Any used or new hot water heater will work as long as it is gas, with a built-in center stack/vent. Electric heaters will not work because they lack this vent.
  • Used truck rim. The correct rim is known as a Dayton rim, and it is used on large trucks with 20-inch or larger tires. Most tire shops will have these laying around. These truck rims have no bolt pattern, and are hollow in the middle.
  • A barn door hinge.
  • Two, 5-foot sections of angle iron. Old bed frame material works fine.
  • A piece of 1/4-inch or 3/8-inch thick steel, large enough to cover the wheel when it is laying on its side.
Use a cutting torch or grinder to cut a side door into the rim. This is where you will feed wood into the heater. Weld the hinge to the section you cut out, and to the wheel. See the first picture.
Cut adapter plate out of 1/4-inch or 3/8-inch steel. The adapter plate will be basically a large washer, that will fit the bottom of gas water heater opening to the truck rim opening.
Weld the angle iron to the bottom, as in the second photo.
Leave the bottom open and set it on a brick base.
This heater will make more hot water than you can imagine. Once the water is hot and you have a good bed of coals in the base, you have enough hot water to take 6 long showers in a row and still scald a pig with whats left. Great camp site hot water, no propane to buy or run out.

If you get fire too hot, the water heater pop off valve will relieve the excess pressure and let cold water in. This set up is cheap to use.
Once the water is hot, it will stay hot for 24 to 36 hours depending on out side temperature. If you add insulation it will stay hot even longer. This idea even could be used as a  hot water boiler for heating the house in cold weather.
Warning: this water heater is for outside or out-building use only; it is not safe for use in a dwelling or any building attached to a dwelling.

Mark is the author of the Water Well Drilling Troubleshooting Guide

He may be reached at or

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