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Wednesday, February 29, 2012

Hearth Centre

The Masonry Heater ~ our hearth centre, our main source of heat.   The idea is that small, hot fires warm up the immense thermal mass, which then becomes the source of heat, as opposed to feeding a woodstove all...day...long, knowing that most of the heat is going out the chimney.   

The first masonry heater we saw was in a large, 2 storey restaurant in  Mt. Tremblant, Quebec, and at -20C, between the heater and the open kitchen, (and the bodies), the place was toasty!  Masonry heaters can serve as the primary heater in a modern home of 1500 to 2000 sq. ft (140 to 185 m2), particularly when located in the middle of an open plan living space.  On each firing of 50 lbs (22 kg) of wood, a Temp-Cast 2000 fireplace can deliver up to 250,000 BTUs (73.2 kw) of radiant heat. Total heat output is controlled by the amount of fuel burned, while the rate at which heat is delivered remains relatively constant.  Some exceptions to these guidelines are noteworthy. Thermal mass construction, such as log homes, earth-sheltered homes, sod homes, and even straw-wall homes are perfectly suited to radiant masonry heaters. The structural mass retains a large portion of the heat from the fireplace and radiates it back to the occupants, allowing it to heat more area, or to be burned less often (www.tempcast.com)

Not only one of the most efficient ways to burn wood to heat a building, masonry heaters are beautiful as well.  Here are some of the stages in building ours:
The Tempcast 2000 masonry heater core kit assembled.  This was shipped from Toronto, Ontario,  and though not huge in size, it was HEAVY! 


 Masonry heaters work by radiating the energy stored in their masonry mass. Heaters like the Temp-Cast 2000 are simply heat storage banks. A short, hot fire heats the masonry mass, which stores and radiates it back to the space slowly and evenly for many hours. This creates a very gentle heater, with almost imperceptible warmth. Radiant heat from a masonry heater is very similar to the radiant heat from the sun. Just as the sun warms the earth, the masonry stove heats by warming solid objects in the home, such as walls, floors, furniture and people. And like a miniature sun in the centre of your home, this radiant energy from the heater does not directly heat the air that it travels through, which has some important health benefits, detailed in Section 2 (see website).  From the first time the fireplace is fired, the heating cycle is very even, only slightly cooler in the morning than in the previous evening. This is quite unlike traditional wood heating systems, which create a very hot space around them, cool considerably during the night and then super-heat the area when re-loaded in the morning. In addition, radiant masonry heating produces an "all over" warmth, as the solid objects in the area are warmed and then re-radiate the warmth to you.(www.tempcast.com)
Normally, people face their masonry heaters with brick or stone, but, having become enamoured of clay, sand and straw, we opted for cob, instead.  (Plus, we had a big pile o clay sitting outside!).  We made bricks and one by one, built it up, and around.  Here, you can see them being laid over and on cardboard, which is used as an air "layer" between the bricks and the cob.







We even made shelves with cob, you know, for the nick nacks in our life!  Important stuff!


 ... and there it stands, the heart of our home, complete with decorative shelves, sculpted from cob. Next step, build the chimney, and then apply a finishing layer of plaster, and whatever decorative touches we decide on.  (Note: the chimney is done, and we are ready to plaster it and the masonry heater during our second Earth Plaster workshop, to be held in June 2012!)


 







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