Green Hearth Appliances
An Introduction
There is very little information available to the public about the advanced technology, hearth appliances, fireplaces and stoves that are available today. These hearth appliances are available in a wide variety of fuel types, sizes, styles and prices. Some are designed to emphasize low cost and others are designed to be large and spectacular. Others are designed to be efficient, high performance, green heating sources using the latest in combustion technologies and features.
Some hearth appliances are green because they use carbon neutral biomass energy sources that create no net increase in atmospheric CO2 and are renewable and sustainable. Others are green because their overall efficiencies are high and they produce less CO2 than conventional, central heating systems.
Green Hearth Appliance Types
Green hearth appliances use a variety of fuels, including natural gas, propane and biomass wood fuels. Biomass wood fuels include dry cordwood and wood pellets. Hearth appliances using other energy sources, including electricity and coal are not considered green at this time. Only biomass burning hearth appliances that use the latest clean burning and high efficiency technologies are considered green.
Electric hearth appliances have a very low overall delivered efficiency and primarily use coal as their energy source. Coal burning is not considered green in that it is not carbon neutral, not renewable and emits a significant amount of unwanted combustion products relative to natural gas.
1. Biomass Hearth Appliances
In the energy production industry, biomass refers to living and recently dead biological material which can be used as fuel or for industrial production. The hearth appliances that use a wood biomass energy source are high performance, certified clean burning wood stoves, certified clean burning fireplaces, high efficiency masonry heaters and pellet stoves.
Wood Biomass - No Global Warming It's now generally accepted by most climate scientists that global warming is by far the most serious environmental threat that the world faces and that increased atmospheric CO2 is contributing to global warming. The emission of fine particulates is not considered a significant worldwide problem, relative to global warming. New technology, biomass hearth appliances burning wood products do produce small amounts of invisible particulates, typically 3 to 4 grams per hour, but they do not contribute to the earth's greatest environmental threat, global warming. How is this possible?
The answer lies in the fact there is no increase in greenhouse gas, CO2 , when wood is burned. Wood is part of a natural carbon cycle where tree photosynthesis removes as much CO2 from the atmosphere as forest decomposition and forest fires put back into the atmosphere. This is a carbon neutral process so it produces no net CO2.
Critics say that wood burning is not carbon neutral because more trees have to be planted to maintain neutrality. It is true that the wood carbon cycle is "process dependent" in that if the earth's forests are reduced... CO2 will be increased and carbon neutrality will be lost. Critics forget that right now an estimated 99+% of wood waste suitable for biomass appliances is lost. It either decomposes in the forest, or is burned in extremely polluting forest management practices. These practices include burning, slash pile burning or in many forest fires caused by excessive human fire prevention. While these practices are cost effective, they provide no opportunity to take advantage of the tremendous energy resources that are currently wasted forest burning and in forest wood decomposition.
It will take many decades of dramatic increases in biomass wood heating to utilize this tremendous waste of biomass energy that occurs in our forests and to upset the carbon neutrality of biomass wood heating. When and if this ever occurs, new forested areas can easily be planted for harvesting using high density "coppicing", thereby maintaining carbon neutrality for many decades to come.
Wood Biomass - Renewable and sustainable Wood biomass heating is obviously renewable and sustainable. Renewable energy resources are virtually inexhaustible in duration but limited in the amount of energy that is available per unit of time. Renewable energy resources include biomass, hydropower, geothermal, solar, wind, ocean thermal, wave action, and tidal action.
There are some limitations on the sustainability of residential heating with pellets relative to wood in that current pellet production processes are dependent on an adequate supply of wood by-products products from saw mills. As the demand for pellets increases, new processes will have to be developed to use forest waste. In the future, the use of wood by-products can be supplemented by pelletizing some kinds of agricultural waste. This will require the development of improved pellet appliances themselves.
Biomass residential wood and pellet heating is currently renewable and sustainable and can continue to be for centuries, using improved forest management processes and using improved pellet appliances.
Wood Biomass - High Efficiency and Clean Burning Some types of new hearth appliances use new technology and are dramatically cleaner burning and more efficient than traditional wood stoves and open wood burning fireplaces. These appliances are EPA Certified, clean burning fireplaces and stoves and pellet stoves. Overall efficiencies average 70+% and they operate with no visible smoke.
Traditional open burning fireplaces and older wood stoves are not green heating sources even though they use carbon neutral and renewable fuel. Traditional fireplaces burn wood at very low temperatures which results in very low efficiency combustion (10%), indoor air quality problems and high amounts of particulate matter emissions. Older wood stoves burn wood at low temperatures in a restricted oxygen environment. This also results in low efficiency (40%) and produces very high amounts of particulate matter emissions.
Wood Biomass - But Not for Everyone Biomass residential wood and pellet heating using new technology, clean burning appliances is very environmentally friendly, very efficient and low cost, but it does have limitations:
- It is only suitable where the transportation cost (carbon footprint) is low.
- It requires proper maintenance and operation of the appliance.
- It requires more work to maintain the fuel supply than natural gas.
- If biomass wood heating substantially increases, forests will have to be managed properly to harvest the vast amounts of wasted wood energy
Clearly, biomass residential wood heating using certified clean burning wood stoves, fireplaces and pellet stoves is not for everyone. But, tremendous reductions of fossil fuel consumption, foreign energy importation and reductions in global warming gasses can be achieved with increased new technology, biomass wood heating.
2. Natural Gas and Propane Hearth Appliances
Some natural gas and propane hearth appliances are green and some are not. These green gas fireplaces and stoves have several distinguishing features. They are listed as room heaters and they are high performance and more efficient overall than many ducted central heating systems because they have no duct losses. Central heating system duct losses average 25% to 40%, reducing the overall efficiencies of furnaces. Hearth appliances are also more efficient because as "zone" heaters, they do not waste energy heating rooms not being used. Additionally, they provide a significant amount of enjoyable radiant heat, reducing the amount of forced air circulated microbes, pollutants and mold spores. An additional feature of these green, gas hearth appliances is that they use "direct vent" exhaust systems, eliminating indoor air quality problems. They also use electronic ignition systems, eliminating standing pilots. In summary, the distinguishing features of green, gas hearth appliances are:
- Listed high efficiency room heater
- No duct losses
- Zone heater
- Radiant heater
- Direct vent exhaust system
- Electronic ignition
For further information on the carbon neutrality of wood burning see:
1. US Environmental Protection Agency
2. Union of Concerned Scientists
For further information on wood biomass renewability see:
US Energy Information Administration
For further information on duct losses see:
3. OIKOS Green Building Source
4. Bonneville Power Administration
5. US Environmental protection Agency Energy Star
