Philip S. Wenz
If someone asked you to design an ideal household heater, where would you begin? Should it burn renewable fuel? Should its efficiency be higher than that of any other household heating appliance, extracting the most heat from its fuel while yielding the least pollution? Should the heater be attractive, compact, easy to install, inexpensive and manufactured using available technology?
There’s no need to run to your drawing board — the dream heater already exists. It’s called a pellet stove. Developed in the 1970s to Environmental Protection Agency specifications, pellet stoves burn enormous quantities of lumber-mill sawdust and agricultural waste that used to end up as landfill. The “pure” sawdust and waste (no toxic additives are needed for combustion) is dried and compressed into small pellets and sold in 40-pound bags at hardware, garden and fireplace stores.
Compression increases the amount of energy stored in the pellets, compared to that stored in a natural log, for example, and reduces the moisture content so they burn more easily. The pellets’ uniform shape and high surface-area-to-volume ratio greatly increase their exposure to air, facilitating virtually complete combustion and almost eliminating emissions. The tiny amount of ash remaining in your stove can be recycled in your garden.
Since the pellets are made from plant material, they are “carbon neutral.” Plants use atmospheric carbon dioxide to build their tissue — from which the pellets are ultimately extracted — and that same carbon dioxide is released back into the atmosphere when the pellets are burned, to be taken up again by plants. Burning fossil fuels, by contrast, puts carbon dioxide that was stored beneath the ground millions of years ago back into the atmosphere, steadily raising the percentage of greenhouse gas.
Heating with pellets is currently 15 to 20 percent cheaper than heating with fossil fuels. To get the best price, buy pellets in bulk and in the off season. Depending on your local climate and the size of your house, you can buy from one to three tons of pellets in the summer and lock in your fuel costs for the coming winter. Pellets come in two grades: premium and standard. Although somewhat cheaper, standard pellets produce a lot less heat and a lot more smoke, and they require constant stove cleaning. Premium pellets are the best buy.
Pellet stoves feature a pleasant, visible flame (behind glass), and they come in a variety of shapes that mimic traditional free-standing wood stoves and wall fireplaces — including inserts for existing fireplaces. But the resemblance stops there. Pellet stoves are motorized, utilizing a small auger to move the pellets from a built-in hopper — where you load them about once a day — to the combustion chamber. Combustion is initiated electrically and maintained through the automatic addition of fresh pellets. Most contemporary pellet stoves have small computers to regulate the auger feed and built-in thermostats. A small fan blows the warmed air into the room. Electricity to run a pellet stove averages nine dollars a month.
Pellet stoves require maintenance, and an annual inspection by a certified technician is recommended (just like chimney cleanings for traditional fireplaces and inspections for gas furnaces). The glass doors should be cleaned and the ash emptied every three to ten days.
Pellet stoves cost between $1,500 and $3,000. However, because they burn so cleanly, they don’t require a traditional chimney — just a metal flue diverted through the wall. Installation is simple and relatively inexpensive.
A mid-sized pellet stove (60,000 BTU) can heat a “typical” 2,000-square-foot home. However, if your home is much larger, consider installing two smaller stoves to avoid overheating the area near the stove while leaving other rooms cold. Heat can be distributed with a ceiling fan in the stove room.
Installing a pellet stove usually requires a permit. Because of arcane restrictions in building codes, a pellet stove may not qualify as your home’s primary heat source, so you should check with your local building department before purchasing one.
However, a pellet stove makes a great secondary heater which, for all practical purposes, can become your primary heater. If you’re like us, you’ll seldom run your gas furnace after you install a pellet stove in your ecological house.