Wood stoves

A wood stove is the most popular, flexible and economical wood heating option. A stove can be located almost anywhere there is enough space and where its chimney can be properly routed. A perfect installation has the stove located centrally in the main floor living area of the house and the flue pipe running straight up into the chimney. This installation design will provide the best performance and need the least amount of maintenance.

Wood stoves are for space heating

A wood stove is defined as a space heater and space heaters are intended to heat a space directly, unlike a central heating furnace, which supplies its heat to the house through a system of ducts. But because modern houses conserve energy more effectively than older houses and need less heat to stay warm, it is now possible to heat an average-size modern home with a single space heater, provided it is located in the main living area.

If you want to heat most or all of your house with a wood stove, try to meet these two objectives: First, the heater should be located in the area where the family spends most of its time. And second, there should be ways for the heat to flow to other parts of the house. These conditions are not usually difficult to meet, but they do need to be planned. 

Put the stove in the area you spend your time    

  For heat upstairs, don't put the stove in the basement

Stove heat output versus room size 

Houses of open plan design with fewer separations between rooms can be heated entirely with a space heater, depending on their size and energy efficiency. In an open plan house, a larger appliance can be used without overheating the space. 

Correct stove sizing is important because a stove too large for the heat demand of the space will be operated with slow, smoldering fires much of the time to avoid overheating the room, and an undersized stove can be damaged by frequent over-firing to keep up with heat demand. 

A wood heat retailer is the best person to advise you on stove sizing for your home. Since experienced retailers know the performance of each stove, they can help you match a stove to your heating objectives and the location you have selected for it. When you visit a retail store to look over the available options, take along a floor plan of your house. This will save time and help the salesperson give you better advice.

  Stove structural design 

Some aspects of the design of wood stoves are related more to looks and personal preference than to performance. For example, there is no functional difference between cast iron or plate steel construction, and painted or enameled finishes. These differences affect appearance and cost but not heating performance.

Although the bottom and rear of all new stoves are shielded to prevent overheating of the floor and to permit close clearances to combustible walls, some stoves have shielded sides and top as well. The more shielded a stove is, the more of its heat is delivered to the room by warm air convection than by direct radiation from the hot stove surfaces. 

Some specialists say that fully shielded stoves are better for small spaces because the hot air they produce more readily travels to other areas and because they don't feel as hot when you sit near them. In practical terms, however, most modern stoves have both radiant and convective characteristics.

  Combustion design 

The internal design of wood stoves has changed entirely in the past 15 years, as the result of the U.S. Environmental Protection Agency regulation established in the late 1980s. The EPA's mandatory smoke emission limit for wood stoves is 7.5 grams of smoke per hour.  Today, all wood stoves and fireplace inserts, and some factory-built fireplaces sold in the U.S. must meet this limit. Stove manufacturers have improved their combustion technologies over the years, and now some newer stoves have certified emissions in the 1 to 4 g/h range. The EPA certified emission rate is a reliable number that can be compared from one model to the next, but a one or two gram per hour difference in smoke emissions does not mean much in day-to-day use.

The two general approaches to meeting the EPA smoke emission limits are catalytic and non-catalytic combustion. Both approaches have proved effective, but there are performance differences. In catalytic combustion the smoky exhaust is passed through a coated ceramic honeycomb inside the stove where the smoke gases and particles ignite and burn. Catalytic stoves are capable of producing a long, even heat output. All catalytic stoves have a lever-operated catalyst bypass damper which is opened for starting and reloading. The catalytic honeycomb degrades over time and must be replaced, but its durability is largely in the hands of the stove user. The catalyst can last more than six seasons if the stove is used properly, but if the stove is over-fired, garbage is burned and regular cleaning and maintenance are not done, the catalyst may break down in as little as two years.  

Cross section of a catalytic stove, showing combustion air/exhaust flow patterns, the catalytic element and the bypass damper.	Cross section of a non-catalytic stove, showing combustion air/exhaust flow patterns, large baffle and high level combustion air supply.

Non-catalytic stoves do not use a catalyst, but have three internal characteristics that create a good environment for complete combustion. These are firebox insulation, a large baffle to produce a longer, hotter gas flow path and pre-heated combustion air introduced through small holes above the fuel in the firebox. Non-cats cannot match the even heat output of catalytic stoves, but their owners love watching the beautiful fire they create. The baffle and some other internal parts of a non-catalytic stove will need replacement from time to time as they deteriorate with the high heat of efficient combustion.

Although most of the stoves on the market are non-cats, some of the most popular high-end stoves use catalytic combustion. Because they are slightly more complicated to operate, and the best of them do produce exceptional performance, catalytic stoves are suited to people who like technology and are prepared to maintain it properly so it continues to operate at peak performance. Both options have their pros and cons, and most users of either type seem satisfied with the performance of their stoves.

  Why advanced stoves are worth the extra cost

1.  On average, advanced, EPA certified stoves are about one-third more efficient than the old box, pot belly, or step stoves, and almost all of the currently available central wood heating furnaces and boilers. That’s one-third less cost if you buy firewood, or one-third less cutting, hauling and stacking if you cut your own. Although this higher efficiency is a by-product of mandatory emissions limits, it has made the EPA rules a winner for both the environment and stove users. The extra cost of advanced technology is about $200 per stove. Over just two seasons of wood burning the greater efficiency of the stove will more than compensate for the higher initial cost.

2. Advanced stoves produce about 90 percent less particulate matter - smoke - than older stoves. After a fire is ignited, you should see no visible smoke from the chimney, so neighbors won't complain and the foul smell, and thick smoke won't blanket your yard either.

3. Fires ignite more easily and burn more completely in these new stoves. The result is a far more convenient and pleasurable wood burning experience.

4. Virtually all the new stoves have a glass panel in their door and an air-wash system to keep it clear. This not only means being able to monitor the fire and adjust it periodically to get a perfect burn, but the fire itself is spectacular to watch. No fire in a conventional stove or fireplace can compare with the beauty of an efficient wood fire. 

5. Ninety percent less smoke means 90 percent less creosote. This gives two important benefits. First, the chance of chimney fire is virtually eliminated, as long as the stove is operated correctly and reasonable maintenance is done. And second, the flue pipe and chimney will need cleaning much less frequently, which is another way the new technology stoves save time and money.