[Cob] Heating cob homes?

[Raduazo at aol.com]

The best heating system for cob or any other home  is passive solar heat. 
Every home weather it is cob, straw bale or timber frame  can be improved by 
passive solar. 
     To make passive solar work you need three  things. 
    1.The sun of course. Lay a compass on the ground  and stand in back of it 
facing south and raise you face to the highest point  where you think the sun 
will be in the winter. Then raise your arms and hold  them at a 90 degree 
angle to your head with your thumbs pointed up. The space  between your thumbs 
represents the eight hours considered to be the golden hours  of solar energy. 
Either you get it or you don't get it.
    2. The second thing you need is insulation. After  you have brought solar 
heat into you home you need to keep it there. Straw bale  is my choice first 
choice because it sequesters CO2 into the wall. Do not get  hung up on bale 
though I had to give up and use 6" studs with R-19 fiberglass  because of other 
design considerations.
    3. The third thing you need is bio-mass or thermal  inertia to store your 
heat till it is needed. There are many materials that can  do this. Brick, 
stone, concrete are all good materials, but cob is the obvious  and hands down 
best choice.
    Many people in designing hoses forget the need for  heat storage. The 
result is a solar heated room that contains 300 pounds of air  and 600 pounds of 
wall panel inside an insulated shell. Say it takes one hour to  raise that 900 
pounds of mass to 90 degrees Fahrenheit. Then what? You open a  window or 
pull the blind and discard the solar energy that you home can not  use.
    But if you line that insulated shell with a  few tons thermal mass it 
takes a long time for the room temperature to  become uncomfortable and you get 
that heat back later. 100 % of the heat stored  in interior walls is recovered.
    Using cob I built an 8 ton wall for a cost of  around $100.00. Most of 
that went for 8000 pounds of sand which I brought home  in 8 trips with my 
pickup truck. It took me one day to build the stem wall  of stone and cement, 8 
days to lay up the cob using a rototiller to mix and mine  clay. It took 2 days 
to apply horse manure plaster. It took 4 days to apply  lime putty and lime 
paint. (The outside is still unfinished.) 
    These were not consecutive days of course but  spread out over a period 
of 6 months, but the point is that I ended up with an 8  ton wall for $100.00 
and 15 days of work. It is my belief that every house  should be designed in 
such a way that if you do not get gas, electric or  oil for a few months the 
house should never drop below freezing, and no  matter how big or small your 
house is you should have one room with a  supplemental heating system. You need 
only one really comfortable room in a  house. Anything more than that is gravy.
    I hope everyone will see Al Gore's movie "An  Inconvenient Truth". The 
point that impressed me the most was that of the need  to take responsibility. 
Example: When AL's mother died of lung cancer his  father gave up growing 
tobacco. This is the kind of taking responsibility that  is needed in our 
leadership and in our lives.
 
Ed