External shading, screens and blinds
The Window Overhang design tool allows for a quick visualization of the shade provided by an overhanging element. Some general assumptions for Melbourne are as follows:
- Latitude: 38° South
- Winter solstice: June 21
- Summer solstice: December 21
As Melbourne is a mild temperate climate zone, a general rule for annual heating and cooling loads in residential dwellings is approximately 80% will be due to heating and 20% due to cooling loads. The reverse is true for commercial buildings where there is a higher cooling requirement throughout the year
The ideal overhanging device for residential dwellings will provide little to no shading during winter to allow for maximum solar heat gain. During the warmer summer months, it is beneficial for the overhanging device to provide shading to the whole window keeping out direct sunlight.