Heat sources produce thermal energy which acts to directly increase air temperature. This thermal load may be absorbed by water vapour.

Internal sources of heat gain production include, but are not limited to, body heat, lighting, machinery and heat passage between rooms.

Heat gains from the external environment are caused by the passage of solar radiation through mediums and structures such as walls, ceilings, glazed window surfaces, doors and the infiltration of external air.

External Heat Gains have a decisive impact on the thermal load of buildings. Window design, surface area and orientation are all factors which affect this loading dramatically.

External versus Internal Shading Systems
Many reputable studies have been conducted into the efficiency of external and internal shading systems. Most of the research has been carried out in Europe where high energy costs make effective insulation of glass areas a must - in fact some countries have tough legislation in place against energy inefficiency.

Research findings by Australian Institutions and summary figures are available through CSIRO.

The objective with any shading device is of course to keep the inside temperature in a range where our bodies feel comfortable and perform at their best.

It has been well established that these temperatures are ranging between 18° and 25° Celsius.

To achieve and maintain this comfort zone we have to spend valuable energy into cooling and heating our homes and workplaces.

Shading & Insulation
External shading systems that also act as barriers against cold winter nights, will save money in 2 ways:

1. The upfront investment into a smaller cooling and heating unit.
2. Ongoing savings in running and maintenance costs.

In case of an environmentally friendly design, cooling or heating may not even be necessary by using external shading and insulation devices (Olympic Village Design).