In the years before we started plundering the earth in search of fossil fuels, most people used to burn wood to heat their homes.
According to the United States Department of Energy, prior to the 20th century, about 90% of Americans used wood as their fuel of choice. Then, as other sources of fuel became more widely available – together with the appropriate appliances needed to burn them to produce heat – this percentage dropped dramatically. In fact, says the Department, by 1970 it had dropped to a mere one percent.
It took the severe energy crisis of the 1970s to turn the trend around. Now the interest in wood as a heating fuel has been revived and it is acknowledged to be a renewable energy source … providing of course the wood is harvested from renewable forests. Another closely related trend is to use special fuel pellets which contain a percent of wood in them.
Of course this has also meant that there is now a growing range of new generation appliances that are suitable for heating your home with wood or with pellets and other biomass fuels. Some pellet fuel appliances are also suitable for burning unlikely items like dried cherry pits, nutshells, corn kernels and even soybeans and beet pulp!
Choosing an Energy-Efficient Heating Appliance for your Home
It is not enough to simply go out and buy a wood or multi fuel stove. For an appliance to be truly energy efficient, it needs to be chosen in terms of the space you are going to heat. One of the biggest mistakes consumers make is to choose a unit that is too big, thinking probably, the bigger the better! But if an appliance is too big for a room, you’re going to end up burning fires at a low smolder so they don’t overheat. That in itself is extremely wasteful AND it causes pollution. Of course on the other hand, if it’s too small, it won’t heat the room adequately.
There are several other things you need to consider in addition to size. One is the capacity the heater has in terms of the warmth it will give out into a certain space; another is the hardy annual – pollution.
When you go shopping for a heater, ask about the British Thermal Units (Btu). Yes British! These are internationally used thermal units that tell us how much space an appliance can heat. For example a 42,000 Btu unit will heat a space that is approximately 1,300 square feet in size, while a larger 60,000 Btu appliance can heat 2,000 square feet. Depending on how your home is constructed, the heater may warm multiple rooms. In any case, the location of any wood heater is also an important factor in terms of distribution of warm air.
Avoid Polluting the Air
In terms of air pollution, unfortunately wood can emit all sorts of harmful compounds including organic gases and carbon monoxide. Because of this, some local authorities will not allow people to use wood-burning appliances at all. Others insist that they are certified by the US Environmental Protection Agency (EPA) – and similar bodies in other countries.
By incorporating a catalytic combustor in the appliance, manufacturers are able to ensure that combustion gases burn at lower temperatures. This has the effect of cleaning the exhaust gas while the appliance generates more heat. Not only are these high-efficiency appliances non-polluting, but they are also safer because they minimize the potentially harmful deposits that build up on the inside of chimney flues.
If you have an older appliance that doesn’t have a catalytic combustor, you should consider retrofitting a catalytic damper that can be installed in the collar of the flue.
Different Types of Wood-burning Appliances
There are various different types of fireplaces and appliances that you can buy for wood fires. There are also similar products manufactured for burning pellets. They include:
- Fireplace inserts and high-efficiency fireplaces that improve the heating efficiency of old open masonry fireplaces. These are fitted into the existing fireplace and incorporate a flue collar that fits into the existing chimney. Inserts should be as airtight as possible.
- Various wood stoves, including new technology catalytic stoves and inserts. The best contemporary wood-burning heaters use new-age wood gasification technology that burns not only the wood fuel, but the combustible gases as well.
- Masonry heaters that produce greater heat and are less polluting than other types of wood or pellet-burning appliances. These incorporate a fireproof firebox that is lined with refractory standard concrete, firebricks or a similar material that withstand extremely high temperatures reaching more than 2,000 °F or 1,093 °C. They also have long twisting smoke channels that run through the masonry mass of firebricks or other masonry material. Some designs look a lot like conventional fireplaces. The main disadvantage with masonry heaters is that they take a while to get hot, unlike wood fireplaces and stoves that heat up quickly.
- Appliances made specifically for burning pellet fuel are exempt from EPA smoke-testing requirements in the USA because they are energy efficient and generate hardly any air pollution. Unlike conventional wood stoves, they can be direct-vented and so don’t need a chimney or a flue. These appliances are available both in the form of freestanding stoves and fireplace insert.
Which Wood-burning Appliance to Choose
There is a huge choice when it comes to wood-burning appliances. So if you are intending to start heating your home with wood, shop around in terms of price, style and quality. It is best to buy a unit that earns energy or biomass tax credits and is certified by the EPA.
The United States Stove Company (www.usstove.com) launched in 1864, when wood was originally a favorite fuel, specializes in both wood and pellet stoves.
Kuma Stoves (http://kumastoves.com/) has not been going for as long as the previous company, but they have been making wood stoves and fireplace inserts for more than three decades, following the energy crisis of the 1970s. Their products are EPA approved and pass the even stricter Washington State standards as well. They also qualify for tax credits.
The Ontario-based Napoleon Fireplaces (www.napoleonfireplaces.com) supplies the full range of stoves and fireplaces to Canada, the USA and to other parts of the world. The company undertakes strict quality testing of its products and uses patented wood-burning technology which is said to exceed EPA standards. The same company also makes Timberwolf wood inserts and wood stoves. (www.timberwolffireplaces.com). Some Timberwolf units are specifically approved for mobile homes.
Another Canadian company, Osburn (www.osburn-mfg.com) services the USA and an overseas market as far afield as Australia and New Zealand. In their early days, the company only produced wood stoves, but now they make fireplace inserts and other types of heaters and stoves as well.
Regency (www.regency-fire.com) manufactures wood stoves, wood inserts and wood fireplaces that are EPA-certified and qualify for the US biomass tax credit. They also manufacture other types of stoves and fireplaces including those made for burning pellets.
Selecting Wood for your appliance
Rule number one, never use wet wood. The best wood fuel will have been harvested in spring and left to dry out through the summer months. However, the wood should not be too dry either. Very dry wood has a tendency to smoke and emit gases, polluting the air and giving off less heat.
Generally all wood species will produce much the same heat levels, although if the wood is dense it will burn longer (so you can expect to pay more for it). Aspen is said to be a great wood for natural cleaning of chimneys.
Well seasoned fire wood normally has a moisture content of between 20% and 25% (measured by weight). Pellet fuels are drier, with a moisture content of around 5% to 10%. Pellets made primarily from wood produce less heat than pellets made from agricultural waste (bark, crop waste and other organic materials), but they produce less ash.