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A warm fire seems to be part of the human spirit. Maybe it's due to something primal, or maybe it's much simpler, just the feel of the warm, radiant glow, the crackling embers, the smell of smoke. Whatever the reason, most people love a fire.
Unfortunately, the home hearth seems to be at odds with modern times. Fireplaces and most wood stoves manufactured before 1988 are known to be serious polluters. They send unfired gasses and unhealthful particulates into the air. Many are also inefficient at heating, consuming more than their share of wood and creating cold drafts. And many receive only occasional use because their owners just don't have time for wood stacking and fire building.
If you like the ambiance and warmth of a fire and the look of a wood stove, but share these concerns, take heart! There is a high-tech answer: the pellet stove. First introduced a decade ago by Whitfield Stoves/Pyro Industries, pellet stoves have become an increasingly popular alternative to wood stoves and fireplaces.
Pellet stoves look similar to wood stoves or fireplace inserts. But there the similarities end. Inside, they are very sophisticated combustion appliances.
THE FUEL
As the name suggests, pellet stoves burn "pellets." These actually are recycled sawdust, wood shavings, walnut and peanut shells, and similar biomass wastes that are ground up, compressed and extruded. They look like rabbet feed and they're sold in convenient 40-pound bags.
Pellets have several advantages over wood. For one, they're environmentally responsible. They turn wastes that would otherwise be dumped at landfills into energy. Intense compression squeezes the moisture out of pellets, dropping their moisture content to below 8%-- very dry, compared to cord wood at from 20% to 30%. The dryer the fuel, the more heat it can produce.
Both because of the fuel's consistency and because of the stove's combustion mechanics, pellets burn very hot. This means they burn cleaner and more efficiently than cord wood. Compared to old wood stoves, which carry from 30 to 50 grams of particulates per hour in their smoke, or new, EPA-certified stoves that give off about 5 grams per hour, pellet stoves have very low particulate emissions, some at less than 1 gram per hour. For example, in independent tests, Breckwell's pellet stove showed less than .27 grams per hour of particulate matter.
Unlike the wood-burning stoves of the 1970s, which converted from 50% to 60% of their fuel to heat, pellet stoves offer 75% to 90% overall efficiency (be sure to look for "overall efficiency" when comparing). In fact, so much heat is extracted that most pellet stoves may be vented horizontally out through a wall instead of through a conventional chimney (see below).
Pellets also create much less ash than cord wood and they don't give off creosote, a common wood stove and fireplace hazard that collects in chimneys, causing chimney fires, and that blackens glass doors.
How does the cost of pellets compare to wood? On face value, pellets are more expensive at $130 to $200 per ton compared to firewood at from $100 to $175 per cord. But comparing a ton to a cord is a bit like comparing a pound to an inch. One ton of pellets consists of 50 bags that weigh 40 pounds each. A cord of wood, which typically measures 4 feet by 4 feet by 8 feet (128 cubic feet) is purchased by volume, a measurement that includes the spaces between stacked logs and the moisture in wood that can't be converted to heat (20% to 30%).
It's better to evaluate usage. Wood stove users burn from 3 to 4 cords of wood per year. An average pellet stovewill use from 1 to 3 tons of pellets per year. Figuring with the costs above, pellets are often less expensive than cord wood. Of couse, with pellets you also save on the time and energy need to stack and carry wood and you need less storage space-- pellets can be stored in only one-third the space needed for cord wood.
Of course, you have to be sure there is an affordable source of pellets nearby. Because freight is a big part of the cost of pellets, the proximity of sources is key. Of the more than 70 pellet mills in the United States and Canada, most are located near lumber mills, furniture manufacturing, or millwork plants. Be sure to ask your wood stove dealer about sources and prices. Also check large grocery and home-improvement store chains; in many parts of the country, pellets are being marketed through these retailers.
HOW THEY WORK
Pellet stoves utilize electronically controlled combustion, blowers, and highly-effective heat exchangers to provide reliable, efficient, heating.
You pour the pellets into a holding bin or hopper, usually located at the top or front. Hoppers typically hold from 35 to 80 pounds of pellets; the larger the hopper, the longer a given stove will burn unattended.
Most stoves have an auger that delivers pellets from the hopper to the combustion chamber. The auger's movement is operated by a solid-state control that is set manually or, for some stoves, by an optional wall-mounted thermostat. A fire's size depends on the rate of feed. Pellets delivered at 1 pound per hour produce a gentle, glowing fire that will last a long time. At 5 pounds per hour, a pellet fire blazes. Depending upon rate of burn and size of hopper, most stoves will operate for from one to two days on a single load of pellets.
The pellets are fed to a fire pot or burner ring in the combustion chamber. Combustion air is blown into the chamber to encourage a super-heated flame. You must light some pellet stoves; others are self-lighting. If they're turned off--or if the power fails--they stop burning.
Room air is drawn in by fan, blown across the heat exchanger that is heated to about 250 degrees, and the warmed air is returned to the room. Unlike wood stoves, pellet stoves rely on convective--not radiant--heat. As a result, most pellet stoves don't get too hot to touch--an important consideration for families with small children. This also means they may be placed closer to combustibles, such as walls (most have a minimum clearance of 3 inches to side walls, 1 inch to back walls). They do, however, need to stand over a minimum 3/8-inch-thick non-combustible floor such as tile.
Residual combustion gasses are vented outside, normally through a 3-inch flue that exits out the unit's back or top. Some, such as the Breckwell, have an interchangeable top/rear vent. Though most pellet stoves don't require a conventional chimney, saving you from considerable expense and design inflexibility, some types work better if the flue goes out through the wall and turns upward about 5 feet, providing natural draw.
BUYING CONSIDERATIONS
Most pellet stoves produce a small fire that, concentrated in the center of the unit, burns hot. If you like the look of a fire, it's important to find a unit with a good flame pattern and large viewing glass. For some stoves, you can get ceramic logs that help disperse the flames and give the fire a more traditional look.
One drawback of pellet stoves is that they're relatively complex. The various moving parts and motors require occasional maintenance. It's a good idea to select a model that gives you easy access to any parts that need care. In regard to maintenance, John Crouch, of the Hearth Products Association, says, "It's not a good idea for consumers who have always maintained their own wood stoves to apply that same approach to their pellet stove. Consumers have a jaundiced view of service contracts, but they may want to consider getting one when they buy a pellet stove because these are an emerging technology and they are complicated."
Also keep in mind that you have to remove the ashes about once a week (with steady use). An easy-to-use, large-capacity ash access drawer makes cleanup easier.
The motors, of course, require electricity (some have battery backup units). A stove will need a nearby 110-volt outlet. If you live where power outages are frequent, you may want to have a gas powered generator on hand.
Pellet stoves are measured in heat output range. Most have a rating of 8,000 to 40,000 BTUs/hr .
A variety of styles are available in both freestanding stoves and fireplace inserts. The largest manufacturer, Whitfield, makes three models: compact units, attractive stoves with generous, bay-shaped viewing doors, and porcelain-enameled stoves. Breckwell and Quadra-Fire stoves have 22-carat gold accents that won't tarnish. Winrich stoves come in 6 different colors, including mauve and sky blue. Waterford has a classic-looking stove that's available in four different enameled colors.
Prices range from about $1300 to $2500 or more for the stove and from $125 to $300 for installation. Vermont stoves, for example, retail at about $2200 with a black finish or $2500 for colored enamels. When comparing prices of pellet stoves with wood stoves, remember that pellet stoves offer a substantial savings--they don't require installation of a full-height conventional chimney or flue, the most costly part of some fireplace and wood stove installations.
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