6. Thermal Performance
Factors Affecting Thermal Efficiency
The main factors influencing good solar design are as follows:

Adequate solar access in cold climates. The building should be oriented such that the
warmth can be harnessed in winter, and cooling breezes captured in summer.

For warm areas, large eaves, verandas, sun-shades and heavy curtains prevent
sunshine from entering and overheating a building during hot weather. Good
ventilation and light-coloured roofs assist the summer cooling process.

For temperate and cool areas, north-facing windows permit the entry of winter sun,
while correctly proportioned eaves restrict the entry of summer sun. Properly sealed
doors and windows allow cross-ventilation in summer and restrict air and heat
leakage in winter.

The inclusion of roof and ceiling insulation, together with high thermal resistance of
the Eco-Block wall system, will limit heat flows to and from the building.

The thermal mass of tiled roofs, Eco-Block Wall System walls and concrete floors will
act as a dampener to heat flows.
Thermal Performance – Heat Transfer
Heat transfers through the fabric of a building by a combination of:
 Conduction
 Convection
 Radiation.
Thermal Mass
If a building with high thermal mass experiences a heating and cooling cycle which crosses
the comfort zone, the roof, walls and floor will store the heat energy for an extended period,
gradually releasing it over time. In winter, high thermal mass buildings will remain relatively
warm, while in summer, they will remain relatively cool.
In winter, heat trying to pass through the wall will become trapped in the wall and part will
slowly pass back into the room. In summer the reverse occurs. Heat trying to pass through
the wall from the outside will become trapped in the wall and part will slowly pass back out of
the building. The thermal mass of the member (wall, roof/ceiling, floor etc) is the combination
of the properties of each of the components and is a function of the mass and specific heat.
Thermal Resistance of Eco-Block Wall Systems
Thickness
mm
Thermal resistance, R
m2.K/W
Eco-Block 230 Series – Concrete 101 mm
External air film
External render
64 mm expanded polystyrene
101 mm reinforced concrete
64 mm expanded polystyrene
10 mm gypsum plasterboard
Internal air film
Total
64
101
64
10
239
0.03
0.01
1.60
0.07
1.60
0.06
0.12
3.49
Eco-Block 280 Series – Concrete 152 mm
External air film
External render
64 mm expanded polystyrene
152 mm reinforced concrete
64 mm expanded polystyrene
10 mm gypsum plasterboard
Internal air film
Total
64
152
64
10
290
0.03
0.01
1.60
0.11
1.60
0.06
0.12
3.53
Material
Eco-Block 330 Series – Concrete 203 mm
External air film
0.03
External render
0.01
64 mm expanded polystyrene
64
1.60
152 mm reinforced concrete
203
0.14
64 mm expanded polystyrene
64
1.60
10 mm gypsum plasterboard
10
0.06
Internal air film
0.12
3.56
Total
341
Notes
This table provides the thermal resistance of Eco-Block Wall System single leaf walls with 10 mm
gypsum plasterboard lining, and without added insulation.
The thermal resistances of Eco-Block Wall Systems are based on:
 Class H expanded polystyrene, in accordance with AS 1366.3-1992, minimum thermal
conductivity, k, of 0.0400 W/m.K
 Reinforced concrete thermal conductivity, k, of 1.44 W/m.K
 Gypsum plasterboard thermal conductivity, k, of 0.170 W/m.K
 Internal and external air film thermal resistances, R = 0.03 and 0.12 m2.K/W, in
accordance with the Building Code of Australia.
 The thermal resistance of the external render, R = 0.01, in accordance with the following
report in Appendix F. Willrath, H., Thermal Properties of Eco-Block, Solar Logic, 20/9/05.
The thermal resistances tabulated herein are minimum expected values, based principally on the
minima specified in AS 1366.3-1992 for Class H expanded polystyrene. These are less than (and
therefore more conservative than) the values reported in Willrath, H., Thermal Properties of EcoBlock, Solar Logic, 20/9/05.