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| ""Temperature determines much of the level
of comfort in light-frame houses during heating season, thus to good heating
insulation is quite important. Of course, the a comfortable temperature is
also determined by the humidity, the type of heating, air circulation, and
other physical parameters of the building. Even what we wear is important!
It is clear that when we compare the insulation properties of different
material- and layered wall structures, we get a wide variety of results.
This can have grave effects on our energy usage.
The better the building’s
heat insulation capabilities, the higher the walls’ temperature, the more
similar the interior temperature, and the less energy we need for heating.
Table 1 illustrates this relationship.
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Table 1. : Various
heat levels in case of -10 0C outside temperature |
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Heat-transmition coefficient:
k (W/m2K) |
Air temperature
(0C) |
Enclosing
structure’s
surface
temperature (0C) |
Energy use
(W/m2h) |
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0,70 |
21,0 |
18,2 |
21 |
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0,39 |
20,2 |
19,0 |
12 |
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0,23 |
20,0 |
19,2 |
5 |
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The building structure’s heat insulation property is measured
by the k heat-transmission coefficient. K shows how much
energy is needed to induce 1 Kelvin temperature change between
two plates of size 1 m2 on the building’s surface.
The weaker the structure’s
insulation capability – when k is a higher value – the
more energy usage is required.
Table 2.
compares the different wall thicknesses for
new and old materials to produce similar
heat-transmission results.
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Table 2.: Various wall structures, given
equal heat-transmission coefficients |
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Succession of layers for external walls k = 0,39 W/m2K |
Wall thickness (cm) |
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1. version: plaster, small bricks (1800 kg/m3), plaster |
193 |
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2. version: plaster, brick blocks (600 kg/m3), plaster |
87 |
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3. version: same as 2., with light mortar |
73 |
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4. version: plaster, aerated concrete block (600 kg/m3), plaster |
59 |
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5. version: brick external wall 11,5 cm,
hollow, 7 cm heat insulation,
masonry 17,5 cm plaster |
41 |
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6. version:
wooden light-frame wall, with 12 cm heat insulation |
21 |
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Table 2. will convince the reader, that a wooden light-frame wall requires only a tenth of the
material needed for a conventional brick wall of equal
heat-transmission properties.
In our wasteful world, older buildings use 150-220 kWh energy per m2 for heating annually. At the same time, wooden light-frame houses consume only 54-100 kWh.
My years of experience have shown, that family homes designed by me – given a 75 m2 house with an occupied attic-space – do not use more than 10 liters of heating oil or more than 7 m3 of gas for a comfortable room temperature. "
Valéria Polyák (Szép Házak - 2000.
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