Outdoor Wood Burning Boilers

Imagine not having any gas or fuel bills this winter. With the addition of an outdoor wood burning boiler or multifuel stoves, this dream could become a reality.

One of the issues with adding a wood burning fireplace or wood burning stove to a home is properly venting the exhaust. Residential building rules require that a wood burning appliance has to have a chimney that extends 3 feet above the peak of the roof. For many applications, this presents a challenge where the costs exceed the benefits. But if you live in a rural area, an outdoor wood burning boiler may be a smart option to help you save big on your electric bills.

Wood Burning Boilers

Wood burning boilers are a fairly simple appliance. They have the look of a small backyard shed and have a combustion chamber that is large enough to put approximately 20 inch logs into. The fire is started in the combustion chamber which heats up the tubes that are filled with glycol or water. Once the boiler reaches a certain temperature, the fluids are pumped from the outdoor boiler to the house via a buried and heavily insulated tube that contains PEX tubing (one line for the supply and one line for the return) encapsulated into one solid tube. The tube goes either into the interior boiler and feeds the heating supply piping or feeds into the forced air furnace heat exchanger where air is blown across the hot coil warming the house. In either set up, the fluid is returned to the boiler through pressure and through the force of the circulation pump at the boiler unit. This cycle continues for as long as the boiler unit is producing heat.

Considerations

One of the main things to consider when having an outdoor boiler installed is where the best location is that is within 50 feet of the house. While longer runs can be used, there is significantly more stress on the circulation pump that will cause premature failure of the pump if not upgraded. This upgrade can be several hundred dollars. Also, because this is a wood burning appliance, the appliance should be located in an area where the wind does not carry the smoke back toward the house in most instances. Otherwise, the home could become soiled on one side with soot from the smoke coming from the chimney. Lastly, this appliance is meant to be used consistently so a lot of wood is needed to keep these units going all winter long. It is important that you do not have to spend a significant amount of money on wood. If you do, then this appliance may not be a good option in terms of cost savings.

Outdoor wood burning stoves are great for rural homeowners who want to save on the cost of buying propane or oil fuel for their heating systems. However, the cost of these units and the estimated heat load should be calculated by an HVAC professional in order to make sure that the unit is properly sized and will be able produce enough output to take care of most of the heat load during the winter.