[Cob] cob thermal mass

[Janet Standeford]

You know, this is all based on the house and the environment interacting 
to produce heat or cold.
When you add in the factor of heating the house with wood or 
electricity, you suddenly have walls taking in the heat from inside. 
When the heat is turned down at night, the walls release heat into the 
house just as if they were heated from the outside.

I know the dream is to not have to use energy to heat or cool a home but 
in real life, we do.

Be aware that if I mention the R value of cob I am talking about the effective R value of 19 per 20 inches: This was the result of an energy model done on a house in Arizona. Their building inspector passed the results on to me and my building officials accept those for my house. If anyone would like a copy of the letter, just let me know. This will be my signature from now on to satisfy Shannon.


On 7/21/2011 3:51 PM, Dean Sherwin wrote:
> At 03:00 PM 7/21/2011, Janet wrote:
>> Be aware that if I mention the R value of cob I am talking about the
>> effective R value of 19 per 20 inches: This was the result of an energy
>> model done on a house in Arizona. Their building inspector passed the
>> results on to me and my building officials accept those for my house. If
>> anyone would like a copy of the letter, just let me know. This will be
>> my signature from now on to satisfy Shannon.
>
> that may very well be true for Arizona.  But it wouldn't be the case 
> in a different climate.  Think for a moment about Alaska, where it 
> could be freezing for days on end.  Thermal mass will not help, the 
> effective R value will be the usual 2-4, since the walls are 
> constantly giving out heat.  Or Miami where it's hot most of the time, 
> tho it would be a bit better there since insulation is not as critical 
> where cooling is called for as with heating, and the nights are a bit 
> cooler. (still it would be unpleasantly hot by nightfall and would 
> take all night to cool, which is why you often see people in India 
> choosing to sleep outside their houses) Thermal mass damps down the 
> process of heat transmission in and out, so that earth building is 
> great where it's at home, in New Mexico say.  But if there are no 
> temperature swings, then what is the mass going to store?
> For most places in the country insulation is one of the most critical 
> aspects of energy efficiency and sustainable building, as I understand 
> it.
>
> Dean Sherwin
> LEED Accredited Professional
> CONSTRUCTION COST MANAGEMENT
> 3, Cherry Street
> PO Box 11
> Media, PA 19063-0011
> (610)892 8860
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