Glazing insulation

Thermal insulation and energy efficiency

Argon and krypton are used as filler gases between panes of glass in double and triple glazing systems. They are selected in preference to air because they provide better thermal insulation. Argon has a thermal conductivity approximately two thirds the value of air, while krypton has a thermal conductivity around one third the value of air. The use of these gases in combination with double glazing can increase the energy efficiency of homes and office buildings by 10%-20% or sometimes more.

Triple glazing with krypton is optimal

Argon is commonly used in insulated glazing as highly affordable and provides a quick return on investment based on its cost premium versus air and the energy savings it will yield. Krypton, which is more expensive than argon, is used to produce thin double glazing units or high performance triple-glazed units. Since it conducts heat less well than argon, a reduced thickness of krypton will result in the same level of thermal insulation.

Argon constitutes almost 1% of atmospheric air and can be extracted in our Coregas air separation units. At Port Kembla, our largest air separation unit and one of the largest in the southern hemisphere, we operate 24 hours per day, 365 days per year to separate air into its main component gases - nitrogen, oxygen and argon - by distillation at cryogenic temperatures. The plant supplies many tonnes per day of gases direct to BlueScope Steel's neighbouring production facility and the rest is distributed to other customers as bulk liquids in road tankers or as gas in cylinders.

Coregas also operates a smaller air separation unit at Mackay in Queensland. This stretches our production capacity, ensures we always have a backup option and ensures speedy deliveries to our customers all the way up the east coast of Australia.

Krypton is present in the atmosphere at only low levels of around 0.0001% and is therefore more expensive due to the many additional process steps required to extract it from air. Argon and krypton are referred to as "noble" gases. They are non-toxic, clear, odorless and chemically inert.

Combining gases with low-e glass is the all season solution

Double and triple glazing window suppliers often combine argon and krypton insulated glazing with Low-E glass to maximise the energy savings for architects, home owners and commercial properties. The gas insulation keeps interiors warmer in winter, while the Low-E glass reflects heat radiation from the sun to reduce the heat gain in the summer season. Low-E glass is treated with a special coating to reduce its emissivity of infra-red light.