Pellet stoves
Pellet stoves offer another way to burn wood cleanly. While they’re similar in concept to wood stoves, they are automated and burn processed biomass, or “pellets.” Pellets are manufactured from compacted sawdust, wood chips, agricultural crop waste, waste paper and other materials. They can also be made from biomass fuels such as nutshells, corn kernels, sunflowers and soybeans. The inch-long chips look like rabbit food. The pressure and heat created during production binds them together without the need for glue. Pellets are manufactured in Alaska, including at Superior Pellet Fuels in North Pole, and are available at local hardware stores and by delivery from manufacturers.
Like a regular wood stove, pellet stoves are designed to heat a space directly rather than througha distribution system (pellet boilers, on the other hand, use a hydronic distribution system). The stove consists of a combustion chamber, ashtray and flue to vent exhaust gases. In a pellet stove, the flue can be direct-vented through a wall, meaning no chimney is required. Pellets are stored in a hopper near the stove, which generally can hold enough pellets for the stove to run for more than a day.
Pellet stoves use electricity to run three motorized systems:
- A screw auger feeds pellets into the fire at a controlled rate
- An exhaust fan vents exhaust gases and draws in combustion air
- A circulating fan forces air through the heat exchanger and into the room
The motorized systems run off a control system and allow pellet stoves to operate automatically.
As with other wood-burning devices, pellet stoves require frequent maintenance, yet less than a wood stove. The stove should be inspected regularly. Also, the hopper must be filled and the ashtray should be emptied on a weekly basis (though this depends on the size of the hopper and ash tray and the frequency of use).
Additionally, the stove should have a yearly check-up. Heating professionals can make sure the doors, gaskets, electric connections and seals on the stove are in good condition and check the chimney for creosote, rust, and corrosion.
Pellet stove efficiency ratings published by manufacturers combine electrical efficiency, combustion efficiency (a measure of the heat produced from burning fuel), and heat transfer efficiency. These typically range from 78–80%, with more efficient stoves losing less heat up the chimney and delivering more heat into the home.
While pellet stoves require more maintenance than non-wood burning appliances, they are becoming more popular in Alaska because of their automated features and ability to burn wood cleanly.