Pellet fuel comparisons... Softwood or Hardwood
Quality is More important than Species
If you're new to wood pellet fuel you might find this as interesting as I do. After 25 years in the hearth industry, including eight years with a leading brand of pellet appliances, I've experienced how different pellets burn. Our company is based on the East Coast in New Hampshire, but I am located in Washington State on the West Coast. Depending on which side of the country I'm on, I hear advice for one type of fuel or the other, and it's pretty consistent. On the West coast, if given the choice, softwood is preferred. On the East coast, it's hardwood.
Traditionally, hardwood has been the preferred fuel in wood stoves and fireplaces because it naturally has a lower moisture content, is a denser fuel, burns longer, and has hotter coals. Softwood is known for buring hotter initially, easy to light, having more pitch or sap, more sparks and sound as it burns, but burns up more quickly. The pelletizing process takes away many of these differences, and at PetetSales.com, we test all of our pellet brands, ensuring you're receiving a consistent quality product whether it's softwood or hardwood.
After wood chips are ground into sawdust, they are dried to a concistent moisture level. the sawdust is then compressed into pellets at a common density, about 40lbs. per cubic foot. It doesn't matter if the sawdust came from a softwood species, hardwood species, or a blend; they are all compressed to the same density. If you look at BTU's of different species of wood, they are similar. Wood pellets are about 8,000 BTUs per pound at 6% moisture.
Quality is most important. After you normalize the moisture content and density, the wood pellets have about the same heat value, but there are still some differences between pellet mills and brands. Ash content, ash characteristics. and pellet length do affect burn and maintenance requirements.
While premium pellets are all under 1% ash content, that could be anywhere from around .25% to .8%. After 10 bags of fuel (or approximately 400 lbs.), that could make th difference between 1lb. of ash or over 3 lbs. of ash. With good maintenance habits, you may not even notice, but it's still three times the ash.
The ash has to go somewhere. Some ash is very high in heavy materials that in extreme temperatures will melt and reharden into dirty glass, forming clinkers and scale in the firepot. Some ash will collect in the firebox as heavy fly ash, while some lighter fly ash will collect in your heat exchanger. Still more could settle in your vent system, with the lightest ash being exhausted out your vent. the difference could be the species, or just the side of the mountain it was grown on. Your appliance will perform best with regular maintenance to keep ash under control.
Pellets also come in different lengths. Usually they are between .25 inches and 1.5 inches. In most pellet appliances, shorter pellets feed faster than longer pellets. As you change from one length to another, you may have to increase or decrease the feed rate of you appliance. In order to get the same burn you may need to decrease the feed rate a little for shorter pellets and increase it for longer pellets. Other than slight changes in feed rate, the burn characteristics and heat value should be very close to the same.
So which should you buy? All fuel sold by PelletSales.com has solid third-party testing data, confirming a quality fuel that will provide great heat value. Have confidence in purchasing both hardwood and softwood blend pellets.