How to Choose an Outdoor Furnace

10/13/2005

The cost of fuel is continually rising. Check out the gas pumps these days and you'll see prices that are higher than ever before. It should come as no surprise that you've also seen a rise in cost for home fuels, like oil and natural gas. With colder weather right around the corner, heating your home will be a large expense.

As a result, many homeowners are looking for more cost-effective ways to heat their homes. Outdoor furnaces are less-expensive alternatives. They can use wood, a renewable resource, to heat the home, garage, pool, hot water, spa and more. The mess of the wood and smoke is kept outside. And these furnaces are safe and efficient to use.

Outdoor furnaces operate on a simple but very efficient principle. They warm water to its optimal heating temperature. The heated water is then piped to desired locations in the home. A pump circulates the heated water to provide proper heat distribution, and automatic controls ensure that the desired temperature is maintained.

As you may be unfamiliar with this type of appliance, here are some major purchasing guidelines for choosing an outdoor furnace from Northwest Manufacturers:

Furnace Size: There are several sizes of furnaces available. The most popular units can heat up to a 5,000 square-foot house. Water volume required by the furnace can vary by manufacturer from a low of about 110 gallons to as many as 600 gallons.

Construction: The heavier the construction, the longer the life of the furnace. The metal used by manufacturers varies in thickness from 1/8 to 3/8 inch. The most commonly used metal is mild steel, which is heavier than stainless, less expensive, and can have as long a life if properly maintained. There is no such thing as a "corrosion-proof" unit. The key to longevity in any furnace is proper maintenance.

Types of control: Most units come with mechanical or analog controls. New electronic controls are now available for more precise temperature control. The unit may be equipped with shut-off controls that turn the unit off when it's not in use, or limit how hot the unit may get.

Overfire air injection: Look for this feature, which increases burn efficiency and reduces smoke by burning off secondary gases.

Door: The larger the door, the easier it is to fill the unit with large chunks of wood. And safety is an important consideration. An air-cooled door will stay cool to the touch. A water-cooled door uses water from inside the unit, creating a hotter door.

Chimney: Chimneys that project up from the top of the unit corrode more slowly than chimneys that project horizontally out the back and make a 90-degree angle turn upward. The pipe angle can serve as a haven for creosote build up.

Unit origin: Many are built domestically, but for those built outside the United States, consider lead times for furnaces and parts.