masonry stoves

Masonry stoves come from a European tradition dating back nearly 500 years. During the period from 1550 to 185o Europe was caught up in an intense cold period known geologically as a Little Ice Age. During this period of time wood for heating homes was at an all time premium and the Europeans needed to be extremely efficient about how they used this scarce resource.  Necessity is genuinely often the mother of invention and in this case the invention was the masonry heater or masonry stove.

Masonry heaters are very large wood stoves usually made from bricks and mortar, hence the term masonry.  They were often free-standing and located in the center of the space to be heated so they could radiate heat in all directions.  Masonry stoves were designed to burn much hotter than a standard wood stove.  Moreover, they are  but able to retain that heat much longer than the traditional fireplaces that preceded them. 

The key to the masonry stove is a series of insulated combustion chambers or baffles.  The baffles prevent heat from dissipating from the combustion chamber and cause internal temperatures to get very high, from 1200 -2000 degrees Fahrenheit.  At these temperatures the hydrocarbon gases ignite, in the same way they wood if you were using a catalytic converter. This means that the maximum amount of energy is obtained from the firewood. Masonry hitters can often achieve efficiencies of 85-90 percent.  In addition, the mass of the masonry itself absorbs much of this heat and then releases it steadily throughout the day. 

One of the ways in which a masonry stoves achieves its high temperatures is providing vents which maximize air flow and which create a good bit of turbulence in the actual firebox.  The fire chamber is usually lined with special fire brick which is extremely heat resistant and which holds the heat in the firebox.  This serves to make the fire hotter but also means that the exterior is somewhat cooler as compared to a cast iron stove (155-175 degrees vs. 500-700 degrees for an iron stove).  This is a particular advantage if you have young kids because they would be less likely to burn themselves on a masonry stove.

Pros and Cons

As discussed above, masonry heaters are efficient and comfortable stoves.  However, they do have some disadvantages. One of them is the sheer mass of the masonry.  Because of this they tend to be extremely heavy.  If you are building a new home your architect can compensate for this, but if you want to retrofit a home with a masonry heater you may discover that your current flooring cannot support the weight.  It is possible to reinforce the flooring with additional joists and support posts but this is something you should have an architect or experienced builder help you analyze. 

Loading a masonry stove with firewood can also be more of a challenge in some cases.  Sometimes the fire chamber is inset well into the masonry so the stove has to be loaded from the rear.  Also, because of all the masonry these types of stoves take up a lot of physical space.  They are probably not practical for very small rooms because of their size.