Between 1973 and 1980, the price of crude oil increased sevenfold. Many homeowners wondered how they would heat their homes if prices continued to climb. Wood heat, long a home-heating fuel in the far north, began to sound like a good idea for the rest of the nation.
Fast-forward 35 years. Wood heat is, once again, hot. Take it from Tom Oyen, president of The Chimney Sweep, Inc., in Washington State. He has been selling wood-heat appliances since 1975. When asked if sales are as strong today as back then, he says, “There are many more people in the showroom today. I don’t see how sales could be any stronger.” Meanwhile, woodstove manufactures are running extra shifts to keep up with the demand.
Despite oil’s recent surge in price, wood heat’s latest success is still surprising. Wood heat has long suffered from the perception that it’s dirty, unsafe, and nowhere near as convenient as turning up the thermostat.
In fact, the improvement of wood-burning appliances is a success story right up there with high-efficiency furnaces, photovoltaics and hybrid cars. New woodstoves are 30% more efficient than old ones, wresting between 70 and 80% of the British thermal units (BTUs) from every log. They’re much cleaner-burning today, too. A new EPA-certified stove, at worst, produces less than 7.5 grams per hour (g/hr) compared to the 40-60 g/hr of older woodstoves. If you use sustainably harvested firewood, you won’t be contributing to global warming at all. That’s because the CO2 emissions that do remain are absorbed by new tree growth at roughly the same rate it is burned.
Cleaner, Safer Stoves
Today’s clean-burning woodstoves (including fireplace inserts and hearth stoves) achieve high levels of combustion with a super-hot, stone-lined firebox and prewarmed combustion air that’s introduced at the top of the firebox from small holes. They are safer, too. More efficient burning reduces the likelihood of chimney fires and means the chimney will need less cleaning.
If you’re heading to a woodstove showroom, your big choices are going to be what fuel you want to burn and whether to buy a stove that gives off heat primarily via convection or radiation. In general, radiant heat stoves are best for when you want to heat one floor of a house that has an open plan. Convection stoves are better for homes with several floors and divided spaces.
The majority of stoves work best with seasoned hardwood logs. Pellet-burning stoves, however, are making big inroads. A pellet burner uses pellets made from compressed sawdust. The pellets automatically drop into a small cup-shaped grate and burn with a fury—leaving barely any ash to clean out later. But pellet stoves don’t work when the power is out—they rely on electricity to feed both fuel and air to the burn chamber, as well as to operate the thermostat.
Beyond Cast Iron
Another very efficient “stove” has gained popularity in the past few decades. Variously called a heat-storing fireplace, masonry heater or masonry stove, it is different from a steel or cast-iron woodstove in two important ways: 1) Their fires are relatively short and very hot; and 2) They are built of a ton or more of stone (usually soapstone) that can store large amounts of heat.
Operation is straightforward. First, build a blazing fire in the combustion chamber. Let it burn for a couple of hours, heating the stone mass. Then close the damper and walk away. The stored heat will radiate from the fireplace’s stone mass for up to 24 hours. Not only do you spend less time building and tending fires, but you have greater peace of mind leaving your home with the fire out but the heat still “on.”
The big downside of masonry heaters is cost. Once you add up the cost of the unit, installation, venting system and structural improvements to support the stove’s weight, a price tag of $30,000 would not be uncommon. Marcia Olenych, owner of Mountain Flame, Inc., a distributor for Tulikivi masonry stoves, says, “Saving on fuel is important but secondary with masonry stoves. These units are more about lifestyle than paybacks.”
CONTACTS: The Chimney Sweep, Inc.; Mountain Flame, Inc.; Tulikivi