Solar Control

Tinted Glass, Timber or Aluminium Louvre Blades

Controlling solar heat gain is important so you can keep out sunlight in summer but let sunlight in during winter to keep the home a comfortable temperature without the need for artificial cooling or heating. Clear glass blades give a high solar heat gain however all windows can use tinted glass to reduce the solar heat gained (SHGC) through windows. A low SHGC indicates that less solar heat is gained through a window, and this is desirable in hot climates and on western orientations. A high SHGC indicates that more solar heat is gained through a window and is desirable in colder climates and on northern orientations.

Altair Louvre Windows can:

• Achieve a Solar Heat Gain Coefficient between 0.1 and 0.72 using glass blades (E.g. Tinted low e glass blades help reduce solar heat gain and provide comparable insulation to double glazing).
• Achieve very little Solar Heat gain by using timber or aluminium louvre blades to completely block out the sunlight while still allowing maximum ventilation through the window.
• Prevent Solar Heat Gain by angling blades while still allowing ventilation.
• Reduce Solar Heat Gain when using metal mesh screens (WERS rated)

Sealing

In winter, the last thing that you want is windows that don’t seal tight and let in cold draughts. Altair Louvre Windows provide tight sealing due to:

• The living hinge design that resists water and air penetration between the clips and the channels.
• An over centre locking mechanism which applies strong locking pressure to blades when fully closed.

Insulation

U-values are the measure of the thermal conductivity of the window. That is, if there is a temperature difference between the air on either side of a window, it measures how quickly heat will pass through the window.

Low U-values allow heat to be transferred through the window slowly, and a high U-value indicates that heat is transferred quickly. The greater the difference between the desired indoor temperature and the outdoor temperature, the more important U-values are. In temperate climates where the outdoor temperatures are seldom extremely hot or extremely cold, the U-value is relatively unimportant.

The U-values of Australian windows range from 2 through to 10. Altair Louvre Windows can achieve rather low U-values (ranging from 2.4 through to 6.9), for example:

• Single glazed Altair Louvres with Low e coatings (or tinted Low e coatings) achieve good U-values that are better than some double glazed windows.
• Secondary glazed Altair Louvres with Low e coatings achieve comparable U-values to many uPVC double glazed windows.
• In extremely cold climates, louvre-fixed lite-louvre combination windows are a good way to achieve good ventilation and very low U-values.
• Altair Louvres with metal mesh screens have WERS ratings which significantly reduces the U-value as the glass blades and the screen act in a similar way to double glazing.

Climate Zone 1, 2 & 3
Hot Summers & Mild/Warm Winters

Objectives

1. Maximise cooling natural ventilation with Altair Louvre Windows.
2. Reduce solar heat gain on East, West and South orientations by using toned glazing, glazing with low e coatings, timber or aluminium louvre blades. Increase solar heat gain on Northern orientation.
3. Reduce conducted heat gain by using windows with lower U-values.

Read the Guide To Ideal Altair Louvre Windows in Climate Zones 1, 2 & 3

Climate Zone 4 & 5
Hot Summers & Cool Winters

Objectives

1. Maximise cooling natural ventilation with Altair Louvre Windows.
2. Reduce solar heat gain on East, West and South orientations. Increase beneficial solar heat gain on Northern orientation (i.e. Northern windows should have clear glazing to allow high SHGC and shading that allows solar exposure in winter).
3. Reduce conducted heat gain and loss by using windows with lower U-values.

Read the Guide To Ideal Altair Louvre Windows in Climate Zones 4 & 5