Got Trees? An Outdoor Wood Furnace
Will Cut Your Energy Bills Down to Size
If you live near a source of cheap wood, you could heat your home for
the entire season with an outdoor wood furnace for the cost of one
month’s electric heat bill. An outdoor furnace requires less tending,
eliminates respiratory problems caused by burning wood indoors, and
keeps the wood burning mess outside.
There are a surprising number of outdoor furnace manufacturers with a
wide range of styles and designs to accommodate different heating
capacities and fuel sources. Some of these furnaces have the capacity
(500k Btu) for commercial applications.
Burns Best makes a corn or wood pellet outdoor furnace. Taylor
Waterstoves has a multi-fuel model that burns coal or wood. And Hardy
Manufacturing makes an all stainless steel outdoor furnace with a built
in hot water exchanger.
|Hardy all stainless
One of the selling points of an outdoor wood furnace is the
convenience of locating it near the wood pile. Since the water
heated by the furnace is pumped to your home through insulated,
underground piping, the furnace can be set up as close as 2 feet,
or as much as 500 feet from your house.
Outdoor furnaces can be adapted to any heating system
All outdoor furnaces are designed to work with any existing heating
system and can be thermostatically controlled. If you have a forced
air system, you can use the existing duct work but you will need to
install a water-to-air heat exchanger in your furnace. Your furnace
is still available as a back up.
If you already have radiant floor heating, you would connect the
underground feed from the outdoor furnace to the existing
For radiant baseboard heat, you can connect the piping directly to
an existing boiler or install a water to water heat exchanger. By
adding the water to water exchanger, you receive the added
benefit of free hot water while the existing furnace functions as
An outdoor boiler can even be used to heat your swimming pool,
driveway, work shop, greenhouse, or multiple buildings.
The firebox designs vary from manufacturer to manufacturer, but all are constructed from
stainless or carbon steel. Although each manufacturer claims to be using a grade of
stainless steel superior to the competition, they all agree that heat transfer efficiency is
almost 3 times better with 16 gauge stainless steel than with 3/8" carbon steel. An all
stainless steel firebox also resists rusting and burnout that occur in standard carbon
Normally, outdoor furnaces are loaded twice a day during peak heating season.
However, burn times per load will vary from 12 to 96 hours depending on what you’re
heating and the outside temperature.
One trait all outdoor wood furnaces have in common is versatility. They are adaptable to
any heat delivery system or fuel, and can be configured to heat anything from a hot tub
to a small factory.