18/03/2021
I'm a big fan of passive solar orientation and use the principles wherever possible when designing.
Solar orientation is the positioning of a building in relation to seasonal variations in the sun’s path as well as prevailing wind patterns. Good orientation can increase the energy efficiency of your home, making it more comfortable to live in and cheaper to run. Orientation for passive heating is about using the sun as a free source of natural heating by letting winter sun in and natural cooling by keeping unwanted summer hot sun out. The ideal orientation for living areas is within the range 15°W–20°E from north, spreading to 20°W–30°E from north is acceptable. It allows shaded windows and glazed doors to admit winter sun to heat the building and exclude summer sun to keep heat out. If not correctly orientated, the dwelling can be dark and cold or too bright and hot. Which means more energy use, higher energy bill costs and extra unnecessary greenhouse gas emissions.
In Adelaide the sun rises in the East and sets in the West. During the summer, the sun is higher (approx. 78deg angle on a northern axis) and in winter it is lower (approx. 32deg angle on a northern axis). Dwellings need to be designed to take both seasonal angles into account. Windows and glazed doors are the main fixture we can use to control this. They can let in too much heat in summer and let out heat in winter if not sized, shaded and positioned correctly.
Aims:
• Minimise windows and glazed doors to the West (shading by wide eaves, Verandahs, Pergolas and Alfrescos can alleviate this). Blocking the hot afternoon sun which makes the dwelling hotter than it needs to be, requiring more electrical cooling (more electrical consumption).
• Optimise windows to the North - constant sun all year round which means plenty of natural light and less need for electrical lighting (lower energy bills, reduced greenhouse gas emissions and improved comfort internally).
• Optimising windows and glazed doors openable portions correctly to South and East for cool breezes in summer to allow ventilation through house to keep cool naturally.
• Shaded full height windows to north to allow lower winter sun in and the shading to block higher summer sun.
• No windows or high, smaller windows to west to reduce impact of hot summer setting sun
• Smaller windows to south to reduce heat loss in winter.
• Planting deciduous plants and trees to north and west so it’s full foliage in summer helps with shading dwelling from heat and it’s shedding of leaves in winter offers transparency for sun pe*******on to heat dwelling.
• Internal and external living areas best positioned to north
• Garages and Utility Rooms best positioned to West
• Bedrooms best positioned to North, East and South
Aim not to do:
• Not optimising windows to north means less light and less winter sun/heat which means more energy consumption for electrical lighting and heating as not naturally supplied to dwelling.
• Not designing to suit best solar orientation is likely to be more costly to build (glazing upgrades, higher rated insulation than necessary etc) and implements extra running costs.
• If the house doesn‘t meet best solar orientation principles, the energy report will be more difficult to achieve the 6 star rating required.
Extra factors to help internal dwelling comfort:
• Double glazing or heat transfer reducing films
• Extra insulation
• Wall materials that help reduce heat transfer
• Light coloured materials and finishes (less heat conductive)
• Ceiling fans for ventilation
• Concrete slab for thermal mass
• Air sealing
Further sustainable factors:
• Solar Power
• Battery Power Storage
• Rainwater storage and use
• Sustainable products
• Thermal wrapping walls and roof
• Airlocks
• Dense curtains
• Roof vents (whirly birds)
• Permeable paving
• Specialised fixtures for low energy use (LED lights)
