From time immemorial mankind has been burning wood as a source of heat. We also found coal to be a good source long ago, especially in industrial settings. The two are often compared, and sometimes one is a clear winner over the other depending on the application. The question is, in this day and age, which one is right for you – and the world at large.
First off the benefits of coal are pretty clear. It is compact, burns well and steadily and is generally predictable from a single source. Different coal deposits do have different components, so there can be some variation if you get your coal from different providers. The downsides are pretty clear, too.
There is a lot of air pollution created when coal burns. Heavy metals are introduced to the air and coal is believed to be one of the chief contributors to the global problem of acid rain. Depending on where you live, coal can be expensive to purchase in small quantities or difficult to store in large enough purchases to be economically feasible. There are long-term environmental impacts from mining coal, such as polluted water tables and long-burning seam fires. Even when the mines do not catch fire, there is an often noticeable shift in the surface above the mine which can cause damage to buildings and ruin otherwise perfectly good farm and ranching land. Not-insignificantly, coal is also a finite resource. There is only so much of it and it will be ages before the planet has a chance to make more.
Wood can be a bit more variable in heat production. Different woods burn at different temperatures and the same type of tree will react differently as a heat source depending on how well it has been cured. It also creates some carbon dioxide emissions during combustion, but they are at lower levels with less additional pollutants than coal. While some would claim deforestation is a product of wood-burning, modern techniques of cultivating trees for harvest eliminate the clearcutting practices of the past.
This practice makes the provision of wood for burning environmentally neutral and creates a completely renewable source of heat.
While coal tends to burn hotter, we know enough about various kinds of wood and how to treat them to create hot-burning, consistent logs from the cultured forests grown. Once it is harvested, the wood is cured to remove excess moisture, which allows it to burn hotter and thereby cleaner. This process creates less emissions and requires less maintenance of chimneys, too.
Different woods will burn at different temperatures, allowing specific applications of the heat to use the tree best suited to its needs. Rather than just cutting down trees and splitting the wood, there are multiple ways in which the renewable resource can be manipulated for our use. In addition to the previously mentioned drying method, the wood can be ground to sawdust and pressed together to create briquettes.
These have less moisture content and tend to be denser than a natural log, so they burn hotter and longer. Similarly processed smaller pellets can be used in automated machines, creating a long-lasting constant fire as they are released over time. These applications are particularly useful in commercial settings or for homeowners wishing to avoid the hassle of throwing another log on the fire. It also has the added benefit of using the whole tree, rather than just logs big or pretty enough to be burned in a home fireplace.
As you can see, while there once may have been clear advantages to coal, they pale in comparison to the flexibility and renew-ability of burning wood in modern times. Not only do you have these added effects, but the devastation caused by accidental fires in a forest is far less severe than a coal fire. While forests can burn for months at a time, there is a coal seam fire in German that has been burning since the 1600s. The devastation of such fires will be prevented if we no longer need to mine coal as a heat source, leaving cleaner air, less polluted ground water, and more stable ground.
One of the greatest crazes in home entertaining and cooking has been the increased interest in outdoor ovens and fireplaces. These features are reminiscent of the old European community ovens. In just the same way the modern versions are places of industry as well as gathering. In summer they allow baking and cooking without creating a sweltering home, and in winter they allow a warm place to snuggle together and get some fresh air. Year round the multipurpose space allows more flexible use of your whole home and yard.
As with the indoor variety of oven, there are numerous construction types and heat sources for outdoor fireplaces. Coal can be a popular fuel, as can gas if your backyard has an accessible line. Both of these have certain benefits for heat overall, but they can be tricky if you want the oven to serve as both a cooking space and one in which to enjoy the flickering of firelight. Coal fires are not always lovely to view, and the inevitable impurities make it difficult to be comfortable cooking directly. Making the heat source indirect can add expense to construction and removes or encumbers its use as a traditional fireplace. Gas can be both lovely to view and used directly as a heat source for cooking, but it has expense issues and may also add complications to construction and zoning requirements. Firewood offers the best of both worlds.
With varying species of tree available as a fuel source, you can adjust the temperature of the fire easily. The burning properties of different woods are well documented, especially if you get them from professionals that kiln dry them to tested moisture levels. In addition to varying species, they often have different forms available including natural logs and briquettes or pellets made from compressed sawdust. The latter two forms can be drier and thereby burn hotter than split logs. This consistency ensures you are able to bake and cook as precisely as you would in your gas or electric cooker inside the home, though it may take a bit of research and experimentation at first. As an added benefit, you can easily introduce certain wood chips like hickory, oak, or pecan to enhance the flavor of your foods with their smoke. When you are ready to enjoy your outdoor feature as a fire pit, there is nothing quite like the flickering flames of natural wood fire crackling away.
There are numerous online and print resources available for building your own outdoor oven from readily available materials, if you are interested. A simple search will give you multiple ideas and help you round out what you want from your new space. While browsing, take into account the space you have available and your primary desired function for the oven or fireplace. Build to the strength you want, but keep your eye out for options to incorporate multipurpose features. Just make sure there are no local ordinances with which you must comply if doing the work yourself. Should you pursue this option, wood is a great choice as a heat source. While it burns hot enough to cook your food, it is less likely to damage your DYI construction with temperature extremes.
Should you choose the professional installation route, many manufacturers know you would like a unit to be as versatile as possible. There are options available in different types of construction material, with or without hybrid heat sources, and you may even request multiple burning pits. You can have a stand-alone heat source or build in surfaces for food preparation and dining. If you go for the hybrid heat source option, you may even want to install a range to facilitate total meal making. The advantage of hiring someone to install your new feature, besides the plethora of options, is being able to pass on the headache of dealing with local government compliance.
Looking at your options may lead you to incorporate other forms of heat, but by and large wood has the most advantages. In addition to those mentioned above, it burns cleaner than coal (especially when using the kiln dried firewood ) and modern harvesting techniques have made it an incredibly renewable resource. Nothing makes a little indulgence feel better than it also being environmentally friendly. Other options include electric type outdoor heating.