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How Wood Pellet Stoves Work


Types of Wood Pellet Stoves

There are two different types of sta­ndard wood pellet stoves: free-standing and insert stoves. If you have an existing fireplace, you can buy an insert that fits into the firebox and vents up the chimney. If not, you can purchase a free-standing unit with it's own exhaust pipe. ­

Pellet stoves come in different sizes, styles and colors, tailored to suit the specific needs of your home. While there are many different models on the market with all kinds of bells and whistles, there are a few key characteristics that differentiate one wood-pellet stove from another.

The first is where the hopper is located. In top feed models, pellets are loaded into the auger from the top of the stove, and the pellets go down a tube into the fire. This design minimizes the chances of the fire burning up to the hopper but is also more likely to get clogged with ashes. For that reason, it requires high-grade pellets that are low-ash. However, the top-feed stoves have the advantage of better heating efficiency because pellets stay in the burn box until they're completely burned. Bottom feed hoppers deliver the pellet horizontally, from behind or beside the fire. This design allows you to use standard grade pellets because the horizontal movement inherently moves ash away from the burn area. This helps keep air inlets open and requires less cleaning of the burn box. However, bottom-feed models may not be as efficient.

Wood pellet stoves are available with different heat output levels to accommodate most room sizes. These levels are measured in Btu, or British thermal units, which is the standard unit of classification used in the heating and cooling industries. The options range from 8,000 to 90,000 Btu, but the majority of models are between 40,000 to 60,000 Btu.

Another stove option is manual or automatic ignition. Manual ignition requires a liquid or gel starter material that's lit with a flame, and the process is similar to starting a fire in a wood burning fireplace. Stoves with automatic ignitions have start buttons, so when you push the button, it feeds pellets into the burn pot and heats the self-igniter.

­ In our next section, we'll weigh the benefits against the disadvantages of pellet stoves.