Window Energy Efficiency

Altair® Louvre Windows are an energy efficient way to control natural light and fresh air into your home or office environment.

Breezway Energy Video

View the energy video above to learn more.

Energy Efficient Altair Louvre Windows

At Breezway, we believe buildings should be designed to work with nature, rather than sealing up and fighting against it. Altair Louvre Windows allow air conditioning and artificial lights to be turned off so you can live naturally.

Altair Louvre Windows offer the following benefits including:

  • Increased energy efficiency, health and productivity of building occupants.
  • Reduced need for air conditioning to keep the room at a comfortable temperature, saving electricity and the running costs of a building.
  • Low U-values required for energy efficiency compliance/excellence.
  • Appropriate U-values and ventilation for all climate zones.

To learn more about the benefits of natural ventilation, Breezway has produced a number of Technical Bulletins to assist with your building designs.

These include:

Fixed Window

Fixed Window

Sliding Window

Sliding Window

Awning Window

Awning Window

Altair Louvre Window Diagram

Altair Louvre Window

*CPD Tutorials*
Breezway offers two formal CPD tutorials to Architects & Designers on Fall Prevention and Ventilation. These have been accredited by AIS. Book today and collect your CPD points!

ventilation rates and energy efficiency video

“Ventilation is an essential element for a naturally comfortable home”

View the Ventilation Video for an in-depth analysis and window comparison.

Cross Flow Ventilation

The importance of window placement.

Breezway Louvres Ventilation Good

Good

Breezway Louvres Ventilation Better

Better

Breezway Louvres Ventilation Best

Best

Breezway Louvres Ventilation Excellent

Excellent

Internal Ventilation

Ventilation openings are often needed in internal walls.

Breezway Louvres Ventilation rooms

The drawing above illustrates how a ventilation adjustable louvre window between rooms is more efficient than just having external louvre windows alone.

Thermal Chimney Effect

Installing windows up high.

Breezway Louvres Ventilation thermal

Another good way to naturally cool a room is to place some Altair Powerlouvre Windows up high. This is effective because rising hot air is able to escape the room through the high up louvres, helping to keep the room cool.

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 0.3 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)
SHGC ratings are part of WERS ratings so please refer to the WERS ratings below or go to the WERS website for more information.
tinted green louvre blades

Tinted Green Louvre Blades

timber louvre blades

Timber Louvre Blades

Breezway living hinge design

Breezway Living Hinge Design

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.
The living hinge and patented clip design of the Altair Louvre pulls the clips tightly against the channel when the window is closed to prevent air leakage and to help it to seal significantly better than the standard required for residential windows.

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 3.8 through to 6.3), for example:

  • Single glazed Altair Louvres with Low e coatings (or tinted Low e coatings) achieve good U-values that are better than many 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.
Breezway Insulation

Australian U-values

While double glazing can give lower U-values than monolithic glass with a low e coating, in many cases double glazed windows have higher (worse) U-values than monolithic glass with a low e coating. Double glazed windows may be more energy efficient however it takes twice as much raw materials to produce and are heavier in weight which means more energy is required to ship and handle the product.

To learn more please read the Breezway Technical Bulletin on Dispelling the Double Glazing Myths

Australian Climate Zones

Choose Altair Louvres to best suit your climate

There are a variety of good Altair Louvre Window design principles that can achieve a comfortable indoor climate, save energy used for heating and cooling and meet the energy efficiency requirements of the National Construction Code.

Climate Zone 123

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 45

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

Climate Zone 678

Climate Zones 6, 7 & 8
Warm/Hot Summers & Cool/Cold Winters

Objectives

  1. Maximise cooling natural ventilation with Altair Louvre Windows.
  2. Increase solar heat gain on Northern orientation. Reduce solar heat gain on East, West and South orientations (Adding or enlarging Northern windows can improve a home’s energy rating).
  3. Reduce conducted heat loss by using windows with lower U-values.

Read the Guide To Ideal Altair Louvre Windows in Climate Zones 6, 7 & 8

WERS Ratings

WERS Certified Products Directory – AFRC (available at www.wers.net)

Blade TypeWERS Windows IDWERS Glazing CodeWERS Cooling Stars9WERS Heating Stars9Uw6SHGC7Tvw8

Breezway Easyscreen Altair Louvre Window System - Single Glazed1

6mm thick clear glassBRZ-006-016Clr6.20.640.68
6mm thick grey tinted glassBRZ-006-076Gy6.20.510.49
6mm thick bronze tinted glassBRZ-006-026Bz6.20.480.39
6mm thick green tinted glassBRZ-006-066Gn6.20.460.57
6mm thick super green tinted glassBRZ-006-056SG6.20.40.5
6mm thick clear low E glass2BRZ-006-086LE4.40.470.66
6mm thick E-Vantage clear glass2BRZ-006-036EVan4.80.480.5
6mm thick E-Vantage grey tinted glass2BRZ-006-046EVanGy4.80.320.21

Easyscreen Altair Louvre Window System - Single Glazed - 105.6mm Gap - Crimsafe Security Screen on Exterior3

6mm thick clear glassBRZ-990-016Clr4.60.30.27
6mm thick grey tinted glassBRZ-990-076Gy4.60.240.13
6mm thick bronze tinted glassBRZ-990-026Brz4.60.250.15
6mm thick green tinted glassBRZ-990-066Gn4.60.250.23
6mm thick super green tinted glassBRZ-990-056SpGn4.60.230.2
6mm thick clear low E glass2BRZ-990-086ET3.60.250.25
6mm thick E-Vantage clear glass2BRZ-990-036EVClr3.70.230.21
6mm thick E-Vantage grey tinted glass2BRZ-990-046EVGrey3.70.20.1

Easyscreen Altair Louvre Window System - Single Glazed - 108.8mm Gap - Invisigard Security Screen on Exterior3

6mm thick clear glassBRZ-991-016Clr4.50.310.28
6mm thick grey tinted glassBRZ-991-076Gy4.50.260.13
6mm thick bronze tinted glassBRZ-991-026Brz4.50.270.16
6mm thick green tinted glassBRZ-991-066Gn4.50.260.24
6mm thick super green tinted glassBRZ-991-056SpGn4.50.250.21
6mm thick clear low E glass2BRZ-991-086ET3.60.260.26
6mm thick E-Vantage clear glass2BRZ-991-036EVClr3.70.250.22
6mm thick E-Vantage grey tinted glass2BRZ-991-046EVGrey3.70.210.1

Easyscreen Altair Louvre Window System - Single Glazed - 109mm Gap - Prowler Proof ForceField Security Screen on Exterior3

6mm thick clear glassBRZ-992-016Clr4.50.310.28
6mm thick grey tinted glassBRZ-992-076Gy4.50.250.13
6mm thick bronze tinted glassBRZ-992-026Brz4.50.260.16
6mm thick green tinted glassBRZ-992-066Gn4.50.260.24
6mm thick super green tinted glassBRZ-992-056SpGn4.50.240.21
6mm thick clear low E glass2BRZ-992-086ET3.60.260.26
6mm thick E-Vantage clear glass2BRZ-992-036EVClr3.70.240.22
6mm thick E-Vantage grey tinted glass2BRZ-992-046EVGrey3.70.200.10

Breezway Easyscreen Fixed Lite Window System - Single Glazed1

6mm thick clear glassBRZ-007-016Clr6.20.720.76
6mm thick grey tinted glassBRZ-007-076Gy6.20.560.55
6mm thick bronze tinted glassBRZ-007-026Bz6.20.530.43
6mm thick green tinted glassBRZ-007-066Gn6.20.510.64
6mm thick super green tinted glassBRZ-007-056SG6.20.440.56
6mm thick clear low E glass2BRZ-007-086LE4.10.530.74
6mm thick E-Vantage clear glass2BRZ-007-036EVan4.50.530.56
6mm thick E-Vantage grey tinted glass2BRZ-007-046EVanGy4.50.350.27

Breezway SL2 Altair Louvre Window System - Single Glazed1

6mm thick clear glassBRZ-003-016Clr60.720.52
6mm thick grey tinted glassBRZ-003-026Gy60.50.26
6mm thick super grey tinted glassBRZ-003-066SpGy60.310.05
6mm thick bronze tinted glassBRZ-003-036Bz60.540.32
6mm thick evergreen tinted glassBRZ-003-046EG60.460.39
6mm thick arctic blue tinted glassBRZ-003-056AB60.460.33
6mm thick clear low E glass2BRZ-003-136LE4.10.620.48

Breezway Altair Louvre Components in a timber frame - Single Glazed1

6mm thick clear glassBRZ-005-016Clr5.60.690.5
6mm thick grey tinted glassBRZ-005-026Gy5.60.480.25
6mm thick super grey tinted glassBRZ-005-066SpGy5.60.30.05
6mm thick bronze tinted glassBRZ-005-036Bz5.60.520.31
6mm thick evergreen tinted glassBRZ-005-046EG5.60.440.38
6mm thick arctic blue tinted glassBRZ-005-056AB5.60.440.32
6mm thick clear low E glass2BRZ-005-136LE3.80.590.46

Ratings by co-principal developer of WERS Dr Peter Lyons
Based on WERS calculation methodology but beyond current AFRC procedures (not available at www.wers.net, only available at www.breezway.com.au)

Blade TypeUwSHGCTvw

Breezway Easyscreen Altair Louvre Window System - Single Glazed4

14mm thick Western Red Cedar timber 54.390.0950
6mm thick hollow extruded aluminium56.550.0760

Notes:

  1. Results disclosed at Australian Fenestration Rating Council (AFRC) regulations.
  2. These blades have a microscopically thin low emissivity coating that is invisible to the naked eye and improves insulation and reduces solar heat gain.
  3. Results disclosed in Standard International Units. Results calculated to the procedures of WERS Screen Rating Methodology, 2012.
  4. These ratings are not authorised WERS ratings and should be regarded as a research report, they have been generated using the WERS calculation methodology but are beyond current AFRC procedures. Calculated performance indices are suitable for comparison with information on the WERS database.
  5. As the optical properties of cedar timber and aluminium are not contained in the International Glazing Databse (IGDB), known, default properties were used.
  6. Uw is the whole window U-value.
  7. SHGCw is the whole windows solar heat gain co-efficient.
  8. Tvw is the whole window visible (light) transmittance.
  9. Star ratings calculated using Nationwide House Energy Rating Software (AccuRate) according to procedures of WERS 2008.

Static Performance (Uw SHGCw Tvw Tdw) calculated using Window 6.3 and Therm 6.3 software (LBNL), 1999-2010.

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