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Heat Gain

“87% of solar gain of a building is through the windows and doors.”

Heat Gain is caused by poor insulation in summer. Aluminium-only frames and non-efficient glass cause the major amount of heat gain. Walls and roof usually contain timber and other materials that have a low conductivity and help to insulate and windows & doors remain as the weak part of the building.

Heat Gain can occur in three ways:

  1. Solar Heat Gain (see right)
  2. Air Infiltration (AI)
    Siphons about half of an average home's heating and cooling energy to the outdoors. Air leakage through and around windows is responsible for much of this loss. Advanced sealing with compressible gaskets and tight hardware reduce air leakage and heat gain in summer through air movement.
  3. Conductive Heat Gain
    Is movement of heat through a material. Aluminium is highly conductive (237) compared to timber (0.21-0.40). Low conductive glass, such as double glazing with minimum air gap of 12mm and low conductive frame, like timber and timber-aluminium minimise conduction.

Particularly in hot climates of middle and north Australia and on windows with a northern elevation it is important to seal the building structure with high performance windows and doors to reduce heat gain.

You can save energy, every day. The right choice decreases your operational costs whilst increasing your comfort levels at the same time.

The benefits of Miglas whole-of-window insulation are:

  • improved comfort all year round
  • reduced heating and cooling of around 40%
  • saves non-renewable resources and reduces greenhouse gas emissions
  • change pays off in approximately 5 to 6 years
  • reduced condensation on walls and ceilings
  • noise reduction

Solar Heat Gain

Is measured by the SHGC (Solar Heat Gain Coefficient) that shows how well a product blocks heat caused by sunlight rays. It is the fraction of incidental solar radiation admitted through a window, both directly transmitted, and absorbed and subsequently released inward.

The SHGC is expressed as a value between 0 and 1. The lower a SHGC, the less solar heat is transmitted.

87% of solar gain of a building is through the windows and doors.

Double, shaded and low-emission glass options installed in Miglas products reduce unwanted heat gain.