When considering glazing, a balance must be achieved between views, ventilation and heat loss and heat gain.
Glazing has to be positioned, sized and protected so as to get the most benefit from the winter sun while avoiding overheating in summer and heat loss in winter.
In winter, windows are used to trap the sun’s heat and warm up the spaces behind. The penetration of the sun into the house is desirable in climates with cool to cold winters. Summer sun penetration is undesirable in all climatic zones in Australia.
Windows must be well shaded in summer. The most effective is external shading in the form of an eaves overhang and pergolas with angled louvres or deciduous vines. Trees and high bushes or operable screens are an effective form of protection on west and east windows.
Things to consider when placing windows are
- Appropriate glass area for each wall orientation
- Using high level windows or skylights to increase solar gain and natural light
- Window opening type for good cross ventilation
- Shading devices to control heat gain and heat loss
- Thermal properties of the complete glazing system