Pellet stoves are heating appliances that burn compressed wood or biomass pellets as a heat source. The pellets come in large bags or can be purchased in bulk. The pellets are slowly dispersed into the burning area by a hopper which is filled up daily and this maintains an even heat. From their first appearance as a standard iron firebox almost 20 years ago pellet stoves morphed into a pleasing feature for any room. (Some newer stoves contain microprocessors which have the ability to run diagnostic tests is a problem comes up.) They can be either fireplace inserts using an existing chimney or as stand-alone units.

Rather than an being and extravagance these stoves solved a few problems:

• First, the outlawing of the “beehive” burners for sawmills – a major source of air pollution in lumber areas - meant that wood waste needed to be disposed in another way.

• Second, when the OPEC embargo of 1973 caused a spike in fossil fuels the traditional oil and furnaces suddenly became an expensive commodity.

Unlike the standard wood stove pellet stoves are easier to clean and the surrounding area stays cleaner because there is none of the debris that accompanies raw firewood. As well, a pellet stove is low in creosote, that blackish sludge that comes from unburnt wood gases and is the main cause of chimney fires. Depending on the model, they may furnish between 10,000 and 60,000 BTU per hour.

Like firewood, which comes from different species of wood, how well a pellet stove burns depends upon the quality of the pellets. For example, top grade pellets produce under one-percent ash content . There are lower grades which can produce between two to four percent ash. However, anyone who goes to the expense of installing a pellet stove would probably use the better quality pellet.

To get the maximum amount of heat pellet stoves uses a forced-air system where a fan pushes air into the combustion chamber like a constant bellows. The second fan produces negative pressure to draw air from the combustion area to the exhaust vent. Unlike regular chimneys this vent can go through the wall but needs a stainless-steel liner.

Good features have are auto-ignition and temperature control. With auto-ignition the stove closes down so that it is not consuming pellets when not needed. You also have the option of manual control for the really cold days when you need extra warmth. However, this creates a warm-cold cycle without an even heat so an automatic temperature control will prevent these interruptions.

There are two (2) types of automatic pellet-feeding systems for the stoves:

Top-feed: There is an augur which directs the pellets to the burner. This auger is inclined which reduces the possibility of fire "burn back" into the pellet hopper. The only drawback with this system is that ash deposits may form on the firebox grate. This could form “clinkers” (deposits usually associated with the old coal systems) which could constrict the airflow and cause the fire to dies. This is another reason to only use the top grade of pellet.

Bottom-feed: The auger on a bottom-feed system augers the fuel horizontally into the fire box. The movement creates a self-cleaning process because the incoming pellets push the deposits and ash into the ash pan. In this system you can use the lower grade pellets

How Much Do They Cost?

You can count on paying between $1400 (very low end) to $3200 for a pellet-burning stoves. This is more expensive than a wood burning stove but you save money on the chimney that is not needed. And if the pellet stove can be vented through an existing chimney then more money is saved.

Wood pellets come 40 pound bags at around $5 a bag or around $250 per ton. For an average winter (New Jersey, Maine or Kansas) the stove could use up to 6 tons for full time heat. In Minnesota this could rise to 8 tons depending on the size of home and system.

BioFuels – Corn, Wheat Sunflower Seeds, Grass

With the heating industry looking toward biomass as a fuel for stoves the first pellet stoves many pellet manufacturers have authorized a blend of corn and pellet. New blends including wheat and sunflower seeds.

A test on dried-grass-fueled stoves revealed that grass has 95% the efficiency of pellets and can be combusted within the stove. As well, in most states the fuel can be made into pellets locally negating the need for long transport costs. One type, switchgrass, has considerable potential to displace oil, natural gas, and electricity in home heating thus significantly reducing greenhouse gases at the same time as heating costs go down. The product can also provide a sustainable income for rural communities. As well, switchgrass can be grown in marginally efficient soil.