Re: GBlist: Insulation ratio walls/roof

[Neil Spiegel <nspiegel@atlasinc.on.ca>]

When you say the 'The myth that heat rises', do you mean to say that:

1) Warm air doesn't rise?
2) Heat does not rise through air?
3) Air does not equilibriate its energy in a closed system?

Not quite sure I understand what the myth is?

And, as a follow-up question what actually happens to these gas molecules of stuff with
higher kinetic and vibrational energy than other molecules in the room. In what way does
the heat dissipate(equilibriate?) from the higher energy molecules to the lower ones? Is
it purely random in direction? Does gravity have no effect? Does heat really not rise?
Freak me out.

I'm not questioning that the attic thing is likely just cause there is more space in the
attic. That makes alot of sense to me. Just wondering about this myth.

Neil

swiftjr@NU.COM wrote:
> 
>    Assuming you are located in a heating dominated climate and have minimal
> stratification, the heat transfer (loss) through a given area of wall is no
> less than (and probably higher in most cases) than the heat loss through
> the same area of ceiling insulated to the same R-value (cathedral or
> attic).  Of course, this is only considering conductive losses and doesn't
> take into account infiltration which is a totally different beast
> altogether.
>       The reasons we see generally see more insulation in the ceiling are
> as follows.
>    The myth that heat rises (this is why air sealing is important -
>    insulation usually can't be relied upon for this).
>    There's more room.  Ceilings are generally the easiest and most cost
>    effective (to a degree) place to beef up your R-value.
>    Building codes require more insulation in the ceiling.  Just for kicks,
>    ask you building inspector why this is code and see what type of
>    response you get.
> 
> Hope this answers your question.
> Joe Swift
> Energy Crafted Home Program
> Connecticut Light and Power
> 
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-- 
Neil Spiegel  
V: 416-534-9792
F: 416-534-7888
E: nspiegel@atlasinc.on.ca
"Why worry about other people's authenticity when you could be worrying about your own?"
______________________________________________________________________
This greenbuilding dialogue is sponsored by CREST <www.crest.org>
Environmental Building News <www.ebuild.com> and Oikos <www.oikos.com>
For  instructions send  e-mail to  greenbuilding-request@crest.org.
______________________________________________________________________