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  Saturday, June 24, 2017  
   
 
A Friendlier Fire: Green fireplaces and stoves

 

In the dark cold of winter, there's nothing like a cozy, warm fire to lift our spirits. Gathering around a fire for warmth and comfort is as old as mankind itself. While our needs for fire today are far different from those of our primitive ancestors, the quality and safety of the fires in our homes are often too much the same: smoky and inefficient. The good news is that we can have both: clean, efficient heat and cozy ambience. There are several environmental considerations as we look at options for space heating:

Outdoor and indoor air pollution

Emissions from wood in the form of smoke contain particu- lates which can be small enough (under 2.5 microns) to lodge deeply in the lungs. Carbon dioxide (CO2) emissions from fossil fuels contribute to climate change. Natural gas and propane are the cleanestburning fuels.

Amount of heat loss when burning fuel

Effects of production of fuels on the environment

Production of heating oil, natural gas and propane all have negative impacts on the environment. There is no environmentally perfect choice when considering space heating, but some are better than others: The Good, The Bad and the Smoky. So, let’s explore them.

Wood Burning Fireplaces are probably the most common and popular form of space heating. No question they are beauti- ful and cozy. But they are also the smokiest and least efficient of all our choices. Same is true for old-style wood-burning stoves (made before 1988).

In interior spaces, exposure to wood smoke is as harmful as being exposed to an equal amount of cigarette smoke. Wood smoke is also an outdoor air polluter. Heat loss is a problem too. Roughly 90% of the heat generated by a wood fireplace goes up the chimney. When you also consider the cold air sucked into the room to fuel the fire, the obvious conclusion is that a wood fireplace as a source of heat represents both the Bad and the Smoky.

On the positive side, wood is a renewable energy source, plentiful and readily available. Also, the growing and harvesting of trees makes a minimal contribution to climate change.

Caution: If you ever decide to burn manufactured logs, be certain they contain no paraffin, a petroleum production that emits toxins when burning.

Wood Burning stoves are a common choice for free- standing space heaters. If this is your choice, purchase one that is EPA-certified and which specifies the unit’s emission level. A catalytic-type design is a better environmental choice. Acting much like the catalytic converter in your car, smoke is passed through a converter which burns gases in the smoke. An EPA- certified catalytic stove generates 4.1 grams or less of particulate matter per hour. When properly maintained, it provides good, even heat with minimum heat loss. The non-catalytic design is less complicated to operate and maintain, but the particulate matter is around 7.5 grams per hour.

Wood-burning stoves are typically made of iron. Soapstone stoves are iron with a soapstone cladding which does a better job of retaining heat. Masonry stoves are in a category of their own.

Masonry heaters are also known as “Russian,” “Siberian,” and “Finnish” fireplaces. They produce more heat and less pollution than any other wood- or pellet-burning appliance. Masonry heaters include a firebox, a large masonry mass (such as bricks), and long twisting smoke channels that run through the masonry mass. You can learn more about them on the Masonry Heater Association of North America web site.

Pellet stoves, common in Europe, are the hottest trend
in space heating. These stoves burn wood pellets which are made generally from sawdust and wood shavings generated by sawmills. They are tightly compacted and dense, enabling them to burn very efficiently and powerfully. Pellet stoves can be either free-standing or installed as inserts into existing fireplaces. The stoves look similar to normal wood burning stoves and inserts, but the components are more sophisticated. A pellet stove has
a “hopper” which holds the pellets. Once the pellets are loaded into the hopper, a device transfers the pellets to the heating
chamber on a controlled and automatic system, using an internal thermostat to gauge the heat and determine when to add more pellets. In most pellet stoves, the air from the room is sucked into the chamber by a built-in fan. The hot air is then distributed back into the room. In some cases it may be desirable to bring the combustion air into the stove from the outside so as to eliminate wasting already heated indoor air to fuel the fire.

Pellet Stoves are so clean that they are exempt from EPA air- quality certification. They are also extremely efficient and easy to use. As an insert, maintenance consists of an annual chimney sweep. As a free-standing stove, weekly cleaning is required. Another positive is that the pellets are an energy-dense fuel from wood waste that would otherwise be heaped into landfills.

Pellet stoves are also made that can burn pellets made from corn, wheat hulls and other bio-mass fuels. However, bio-mass pellets cannot be burned in wood pellet stoves and inserts.

Fireplace Inserts are units which are installed in existing fireplaces and vented through the chimney. They burn wood, gas or wood pellets and offer efficiency superior to a traditional fireplace. Vent-free fireplace inserts require no chimney or flue modification. Most have blowers to circulate the heat. Inserts are used to change an existing non-efficient fireplace into an efficient, heat producing space heat.

Wood-burning inserts, compared to other insert options, are typically more expensive, more difficult to install and require more maintenance in terms of flue cleaning and firebox cleaning. And, of course, they still burn wood which pollutes both indoor and outdoor air.

Wood-pellet burning inserts, like the stoves, are more efficient than their wood-burning counterpart but they require the same maintenance as insert. However, they are far less polluting than wood.

Natural Gas & Propane Log sets are the simplest and most popular insert. They provide the most realistic hearth
fire and lowest initial equipment costs, but like wood fires, much of the heat is lost up the chimney, making these products primarily aesthetic ambiance. They are clean burning and therefore minimize pollution.

Natural Gas & Propane Fireplace Inserts are self- contained units which can provide more heat than natural gas log sets. An existing chimney can be used if an approved flue liner is installed. Unvented gas log sets are also available and do not require chimney or flue modification. Please consult an expert related to unvented gas log sets due to their pro and cons which are debatable.

Gas Fireplaces are installed in place of wood-burning fireplaces. In addition to beautiful fires, natural gas fireplaces can provide a substantial amount of very efficient heat. The amount of heat depends on the type of fireplace purchased. For the aesthetic effect of a beautiful fire, choose a product certified as a “vented gas fireplace.” For heat as well as the ambiance, choose a “vented gas fireplace heater” or a “vent-free roomheater”. Natural gas or propane fireplaces are often equipped with fans which push hot air into the room. Some of the “greener” options include variable flame heights and thermostats that regulate height and intensity of flame and will automatically turn off and on as room temperature modulates. Sealed fireplaces prevent gases from entering interior space. Again, natural gas and propane are very clean burning, minimizing air pollution.

As you can see, there are many factors to consider when purchasing a stove, fireplace insert or fireplace. In addition to the environmental considerations, you’ll need to think about other things: cost, the number of square feet you wish to heat, requirements for cleaning and maintenance, warranty, burn rate, and BTU output. Another consideration is the tax benefits for some high-efficiency products.

No matter what heating appliance you choose, green stoves and fireplaces are a smart choice for your health and the environment. They’re also a smart choice for your pocketbook. Rarely will they cost more than traditional alternatives. And you’ll usually end up saving money in the long run because a high-efficiency stove or insert will reduce the fuel you need to burn to heat your home. But saving money is only one, and maybe not the most important, consideration. Green fireplaces and stoves have other benefits: they provide a healthier home environment for everyone who lives under your roof and the peace of mind and satisfaction that comes with knowing you are making a contribution toward a better world for future generations.