FAQs
Does burning wood pellets produce smoke?
Every time a pellet heater lights there is a short period of time (just a few minutes) when smoke is created as the pellets are igniting. After the fire is going, the fire quickly heats enough to produce a very clean burning fire with no visible smoke.
Why are pellets considered carbon neutral?
Trees absorb carbon as they grow. It doesn't matter if they decompose on the forest floor, burn in a forest fire, or are used to provide heat in a high efficiency pellet appliance; that same carbon is released back into the atmosphere for new trees to absorb.
Doesn't it take energy to make pellets?
Yes it does. The raw materials for pellets have to be transported to the pellet manufacturer and it takes energy to convert them into fuel. The net energy return is still 13 to 1. That means you get 13 times more energy out of pellet fuel than it takes to make them. That's a huge return!
Are Pellet Appliances Clean Burning?
Yes! Very clean. Open wood burning fireplaces and older wood stoves can produce 50 grams of pollutants or more per hour. National EPA standards for particulate emissions (smoke) require that non-catalytic solid fuel burning appliances produce less then 7.5 grams of particulates per hour. Individual states have even more stringent requirements. Washington State limits emissions to 4.5 grams for a non-catalytic appliance. Pellet appliances usually produce less then 2 grams of particulates per hour, and many less than a gram. A gram of particulates is about the size of a pencil eraser.
Wood Heat is Carbon Neutral
Besides producing very low emissions, wood pellets are also a great environmental answer to heat energy needs. By using wood byproducts that would otherwise go to waste, wood pellet manufacturers create a heating source that has very little negative impact on the environment while closing the carbon-cycle loop. Using this short-lived carbon from trees instead of fossil fuels keeps more the long-term storage of carbon in the ground. In some parts of the country, wood pellets are made from trees killed by insect infestations. If those dead trees were left to decompose in the forests, they’d produce more greenhouse gases than they do being used for high efficiency heat.
Operation Variables - Keep it clean!
There are several stages to wood combustion. The most important factors to clean combustion are moisture content of the fuel, temperature, and fuel to air ratio. In a wood burning appliance, there can be a wide range of variability in moisture content of cordwood. The temperature of the firebox is dependent on that moisture content as well as the users ability to set the air controls to the correct fuel to air ratio in order to achieve optimum combustion. In other words, there is room for error with standard wood burning appliances.
In a pellet appliance, those variables are tightly controlled. The moisture content in the fuel is controlled by the pellet manufacturers to a consistent standard. The pellets are compressed to a consistent density range, regardless of brand. The pellet appliance controls the fuel to air ratio buy controlling the lighting sequence, the feed rate as well as the speed of the combustion blower at different heat output settings. By having a consistent fuel moisture content and tightly controlled fuel to air ration, the temperature in the firepot and firebox can be kept very high. Smoke burns between 550 and 1200 degrees. Pellet appliances can achieve temperatures greater than 2000 degrees in the bottom of their firepot depending on the model and the burn rate.
Fuel Variables
Pellet fuel manufacturers follow strict fuel standards developed by the Pellet Fuels Institute or PFI. These includes specifications on diameter, length, durability, density, moisture content, ash content, and sodium content. The specifications define different grades of wood pellets: Super Premium, Premium, Standard, and Utility. By manufacturing pellets to these specifications, appliance manufacturers can ensure consumers of consistent, clean burning operation of the appliance as long as the consumer uses a grade of fuel approved for the appliance. Almost all appliances can burn Premium grade pellets, the grade that most pellet manufacturers make. There are some appliances that can handle standard grade pellets, and even fewer that can burn Utility grade pellets.
Where do wood pellets come from?