There are several types of pellet stoves on the market. We will explain the common types and mention several pros and cons of the different stoves to help you decide what the best type of pellet stove may be for your home.
Top Feed vs. Bottom Feed Pellet Stoves
There are two basic types of pellet stoves, there are fireplace inserts and there are freestanding stoves. Then to further divide them, there are two main types of feeding systems, top fed and bottom fed.
The feeding system is composed of a hopper and a feeding device. The feeding device turns like a big screw and admits pellets into the combustion chamber slowly. There is a distinct advantage of the bottom fed systems because they will help to push the old ash and clinkers out of the way of the new burning fuel. Clinkers are hard rock like deposits that form from ash.
Top fed systems tend to build up clinkers and ash suffocates the flame more. Bottom feed systems force the pellets into the side of the combustion chamber allowing them to push ash forward or to the side, out of the fires path and into the ash pan. Bottom fed stoves can also burn different grades of fuel whereas top fed systems require a higher grade fuel that produces less ash.
There are some minor advantages, however, to the top fed systems. They tend to burn the fuel more completely and are a bit more efficient. They have also been known to burn a little hotter. It is still clear, to most folks though, that a bottom fed system’s advantages outweigh the top fed system’s advantages.
Fuel Source Choices
Pellet stoves are appropriately named for the type of fuel they use. They use fuel pellets that are made from a combination of sawdust, paper waste and agricultural waste. There are different grades of fuel pellets. The premium grade pellets are a bit more expensive, but burn cleaner.
Most top fed pellet stoves require premium grade pellets to keep them from forming clinkers and not burning well. Bottom fed systems work well with either grade of pellets, but premium grade pellets usually cause less harmful pollutants. The standard maximum pellet size is 5/16 of an inch in diameter by 1 ½ inches long. Most are slightly smaller.
Fuel pellets have 5 to 10% moisture content. Well seasoned fire wood has a moisture content of about 20%. Pellet fuels have come more available in the past decade. There are only about 45 pellet fuel manufacturers across the United States however, there are thousands of dealers spread across the country. Before deciding on a pellet stove for your home, make sure that the fuel is readily available in your area.
Some pellet stoves have the ability to use nut shells or small wood chips as fuel as well, but do not use them without checking the manufacturer’s instructions. Most pellet fuels come packaged in 40 pound bags. Premium grade pellet fuels are characterized by a lesser ash content when burned. Pellet fuel with an ash content of 0.05% or less is considered premium grade.
Pellet fuel stoves provide a cleaner solid fuel source than their competitors, fire wood and coal. They are also more convenient because they generally only need refueling once a day. The exteriors of the stoves stay a lot cooler than wood burners and are less of a fire hazard, with the exception of the glass. The glass on pellet stoves still gets really hot and will burn the skin quickly if touched.
Some of the drawbacks of pellet stoves include: They are more complex and expensive to repair. They also require some electricity to power a fan, the feeder and controls, but usually only use about 100 kilowatt-hours a month or about $9 per month. They will not work when the electric is out.
One plus is that most manufacturer’s make all kinds of different units and are not as likely to steer you in the wrong direction when asking what kind may be best for your home. Don’t be afraid to ask the dealer questions before making your purchase. If you have any unanswered questions, they are there to help you decide.