GreenTips

Glass is produced from naturally occurring silica that is a readily available resource, making up 20% of the earth’s surface. However, recycling glass still saves 25 to 32% of the energy required to make new glass.

Glass can be recycled forever and many glass manufacturers produce glass with a high recycled content.

The choice of glazing in a building will have a significant effect on energy use within. Passive solar design can be used to capture the sun’s heat and double glazing is readily available. Triple glazing is available overseas but is not readily available in NZ.

Heat losses through glass can be further reduced by the use of inert glass fill in the glazing units or the application of films to reflect heat back into the building.

Heat gains can also be problematic. External fixed or motorised louvres reduce the energy reaching the surface of the glass. Where these are not possible, solar reflective films, reflective glass and tinting can all be used to reduce solar gains, while modern technology can electronically tint windows to reduce the light and heat energy transmitted.

Artificial lighting is a significant energy use in buildings. Reducing the solar gains can also reduce the daylight reaching the inside. If tinted glass is required, green tinted glass will usually give the best light transmission.

Glass panels can even generate electricity; some systems have photovoltaic cells embedded into the glass itself.

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