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<DIV><FONT color=#000000 size=2>Dear Andre,</FONT></DIV>
<DIV><FONT color=#000000 size=2></FONT> </DIV>
<DIV><FONT color=#000000 size=2></FONT><FONT size=2> If you
add 5 to 5 you have 10, and 5+100=105. In both cases the increase is the same,
but their relative changes are 100% and 5% respectively. So we have to
clarify about what changes we are speaking about. Any way for homogenous
materials R is simply proportional to thickness x ie R=r*x</FONT></DIV>
<DIV><FONT size=2> It would be very interesting for me
to know the source US data. In USA they still frequently use Btu as the energy
unit= 1058J, 1ft= 0,305m, 1F=0,55C,1pound=0,405kg ,Probably the conversion
between them can be done as follow R US [hr-sqft-F/Btu]/5,74 =
R SI [s-m2-K/J]. The European unit is roughly speaking 6 time
bigger.</FONT></DIV>
<DIV><FONT size=2> Rene's remarks are great-one have to take
into account much more data then you proposed to calculate the total heating
power of your house. Once again about "enough". If the price of energy
is zero you can use very poor insulation and it will be optimal one (from
economic point of view). When "energy prices might sky rocket some
day" such house would desequilibrate your budget (or rather mine). I
observe such phenomenon in Poland. Since 10 years thousands and thousands
of old big blocks (immeuble) and small houses are additionally insulated because
the energy costs much more now. </FONT></DIV>
<DIV><FONT size=2></FONT><FONT color=#000000 size=2>Perheaps when you are
speaking "enough insulation" you are thinking about "friendly
house" - friendly for your family,pocket and enviroment.</FONT></DIV>
<DIV><FONT color=#000000 size=2></FONT><FONT size=2>Greetings
Henryk</FONT></DIV>
<DIV><FONT size=2></FONT><FONT face=Arial size=2><B>-----Original
Message-----</B><BR><B>From: </B>Coralie & Andre de Bouter <<A
href="mailto:m.ep@laposte...">m.ep@laposte...</A>><BR><B>To: </B><A
href="mailto:strawbale@amper....muni.cz">strawbale@amper....muni.cz</A> <<A
href="mailto:strawbale@amper....muni.cz">strawbale@amper....muni.cz</A>><BR><B>Date:
</B>Tuesday, June 25, 2002 2:23 PM<BR><B>Subject: </B>Re: [Strawbale] At what
point (R value) do we reach 'enough' insulation?<BR><BR></DIV>
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<DIV><FONT face=Arial size=2>Dear Henryk,</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>I did not experiment, I have my informtion
from several presentations I've seen in the US.</FONT></DIV>
<DIV><FONT face=Arial size=2>What I understood is:</FONT></DIV>
<DIV><FONT face=Arial size=2>When you add 5cm of insulation to a non
insulated building it will make a big difference.</FONT></DIV>
<DIV><FONT face=Arial size=2>However, when you add 5 cm to a building
that allready has 100cm of insulation it will hardly make a difference.
</FONT></DIV>
<DIV><FONT face=Arial size=2>That is how the diagonal (increased
insulation) becomes a curve.</FONT> </DIV>
<DIV> </DIV>
<DIV><FONT face=Arial size=2>This argument was expressed in relation to
the discussion about the R value of SB. Some tests show better results
than other, but all agree that the insulation is 'Good enough!' since
they surpassed the angle in the above mentioned curve. </FONT><FONT
face=Arial size=2>I could contact 'them' in America, but they use an
other R value than we do in Europe. They state about R 40 for SB where
in Europe it seems to be R 6. </FONT><FONT face=Arial size=2>I don't
know how to convert from the American R to the European R.</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=Arial size=2>I agree that the decision on what is good
enough depends on "prices of buildig materials and labour and on
the cost of energy for heating (cooling) you would find
acceptable" However, in one building system the optimum could be
much lower than in an other building system. </FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=Arial size=2>So, if we take the price of the insulation
and heating out of the calculation (since some insulation materials are
extreemly cheap like straw or sheep wool, and energy prices might sky
rocket some day), at what point is it 'enough'? I do realize that
defining 'enough' ('reasonable optimum') will probably be
difficult.</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=Arial size=2>I want to know this because it can give a
scale to judge the effectiveness of a certain solution relative to the
'reasonable optimum'.</FONT></DIV>
<DIV><FONT face=Arial size=2>Rather than giving just an R value (which I
feel is only a number as long as we don't have a frame to place it
in)</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=Arial size=2>I hope this clarifies my
question,</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=Arial size=2>Greetings,</FONT></DIV>
<DIV><FONT face=Arial size=2>Andre</FONT></DIV>
<DIV> </DIV>
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