Window Energy Efficiency

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

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

Sliding Window

Awning Window

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 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.

Good

Better

Best

Excellent

Internal Ventilation

Ventilation openings are often needed in internal walls.

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.

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 0.1 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)

SHGC ratings are part of WERS ratings so please refer to the WERS ratings below or go to the WERS website for more information. To learn more about using timber, please visit our Timber Blade and Frame page.

Tinted Green Louvre Blades

Timber Louvre Blades

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.

Breezway Living Hinge Design

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.

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

Objectives

Maximise cooling natural ventilation with Altair Louvre Windows.
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.
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

Maximise cooling natural ventilation with Altair Louvre Windows.
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).
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 Zones 6, 7 & 8
Warm/Hot Summers & Cool/Cold Winters

Objectives

Maximise cooling natural ventilation with Altair Louvre Windows.
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).
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 Type	WERS Windows ID	WERS Glazing Code	WERS Heating Stars⁹	Uw⁶	SHGC⁷	Tvw⁸
Breezway Easyscreen Altair Louvre Window System - Single Glazed¹
6mm SolTech Neutral	BRZ-006-11	6SolT Ntl		4.5	0.41	0.48
6mm thick clear glass	BRZ-006-01	6Clr		6.2	0.64	0.68
6mm thick grey tinted glass	BRZ-006-07	6Gy		6.2	0.51	0.49
6mm thick bronze tinted glass	BRZ-006-02	6Bz		6.2	0.48	0.39
6mm thick green tinted glass	BRZ-006-06	6Gn		6.2	0.46	0.57
6mm thick super green tinted glass	BRZ-006-05	6SG		6.2	0.4	0.5
6mm thick clear low E glass²	BRZ-006-08	6LE		4.4	0.47	0.66
6mm thick E-Vantage clear glass²	BRZ-006-03	6EVan		4.8	0.48	0.5
6mm thick E-Vantage grey tinted glass²	BRZ-006-04	6EVanGy		4.8	0.32	0.21
Easyscreen Altair Louvre Window System - Single Glazed - 105.6mm Gap - Crimsafe Security Screen on Exterior³
6mm thick clear glass	BRZ-990-01	6Clr		4.6	0.3	0.27
6mm thick grey tinted glass	BRZ-990-07	6Gy		4.6	0.24	0.13
6mm thick bronze tinted glass	BRZ-990-02	6Brz		4.6	0.25	0.15
6mm thick green tinted glass	BRZ-990-06	6Gn		4.6	0.25	0.23
6mm thick super green tinted glass	BRZ-990-05	6SpGn		4.6	0.23	0.2
6mm thick clear low E glass²	BRZ-990-08	6ET		3.6	0.25	0.25
6mm thick E-Vantage clear glass²	BRZ-990-03	6EVClr		3.7	0.23	0.21
6mm thick E-Vantage grey tinted glass²	BRZ-990-04	6EVGrey		3.7	0.2	0.1
Easyscreen Altair Louvre Window System - Single Glazed - 108.8mm Gap - Invisigard Security Screen on Exterior³
6mm thick clear glass	BRZ-991-01	6Clr		4.5	0.31	0.28
6mm thick grey tinted glass	BRZ-991-07	6Gy		4.5	0.26	0.13
6mm thick bronze tinted glass	BRZ-991-02	6Brz		4.5	0.27	0.16
6mm thick green tinted glass	BRZ-991-06	6Gn		4.5	0.26	0.24
6mm thick super green tinted glass	BRZ-991-05	6SpGn		4.5	0.25	0.21
6mm thick clear low E glass²	BRZ-991-08	6ET		3.6	0.26	0.26
6mm thick E-Vantage clear glass²	BRZ-991-03	6EVClr		3.7	0.25	0.22
6mm thick E-Vantage grey tinted glass²	BRZ-991-04	6EVGrey		3.7	0.21	0.1
Easyscreen Altair Louvre Window System - Single Glazed - 109mm Gap - Prowler Proof ForceField Security Screen on Exterior³
6mm thick clear glass	BRZ-992-01	6Clr		4.5	0.31	0.28
6mm thick grey tinted glass	BRZ-992-07	6Gy		4.5	0.25	0.13
6mm thick bronze tinted glass	BRZ-992-02	6Brz		4.5	0.26	0.16
6mm thick green tinted glass	BRZ-992-06	6Gn		4.5	0.26	0.24
6mm thick super green tinted glass	BRZ-992-05	6SpGn		4.5	0.24	0.21
6mm thick clear low E glass²	BRZ-992-08	6ET		3.6	0.26	0.26
6mm thick E-Vantage clear glass²	BRZ-992-03	6EVClr		3.7	0.24	0.22
6mm thick E-Vantage grey tinted glass²	BRZ-992-04	6EVGrey		3.7	0.20	0.10
Breezway Easyscreen Fixed Lite Window System - Single Glazed¹
6mm thick clear glass	BRZ-007-01	6Clr		6.2	0.72	0.76
6mm thick grey tinted glass	BRZ-007-07	6Gy		6.2	0.56	0.55
6mm thick bronze tinted glass	BRZ-007-02	6Bz		6.2	0.53	0.43
6mm thick green tinted glass	BRZ-007-06	6Gn		6.2	0.51	0.64
6mm thick super green tinted glass	BRZ-007-05	6SG		6.2	0.44	0.56
6mm thick clear low E glass²	BRZ-007-08	6LE		4.1	0.53	0.74
6mm thick E-Vantage clear glass²	BRZ-007-03	6EVan		4.5	0.53	0.56
6mm thick E-Vantage grey tinted glass²	BRZ-007-04	6EVanGy		4.5	0.35	0.27
Breezway SL2 Altair Louvre Window System - Single Glazed¹
6mm thick clear glass	BRZ-003-01	6Clr		6	0.72	0.52
6mm thick grey tinted glass	BRZ-003-02	6Gy		6	0.5	0.26
6mm thick super grey tinted glass	BRZ-003-06	6SpGy		6	0.31	0.05
6mm thick bronze tinted glass	BRZ-003-03	6Bz		6	0.54	0.32
6mm thick evergreen tinted glass	BRZ-003-04	6EG		6	0.46	0.39
6mm thick arctic blue tinted glass	BRZ-003-05	6AB		6	0.46	0.33
6mm thick clear low E glass²	BRZ-003-13	6LE		4.1	0.62	0.48
Breezway Innoscreen Altair Louvre Window System - Single Glazed¹
6mm thick clear glass	BRZ-009-01	6Clr		6.9	0.63	0.63
6mm thick grey tinted glass	BRZ-009-02	6Gy	N/A	6.9	0.50	0.46
6mm thick green tinted glass	BRZ-009-08	6Gn	N/A	6.9	0.45	0.54
6mm thick ever green tinted glass	BRZ-009-09	6EG	N/A	6.9	0.40	0.47
6mm thick E-Vantage clear glass²	BRZ-009-04	6EVanClr		5.7	0.48	0.48
6mm thick E-Vantage grey glass²	BRZ-009-10	6EVanGy		5.7	0.32	0.23
6mm thick EnergyTech clear glass²	BRZ-009-03	6ET		5.5	0.53	0.58
6mm thick EnergyTech grey glass²	BRZ-009-07	6ETGy		5.6	0.37	0.28
6mm thick SolTech Neutral glass²	BRZ-009-05	6SolTNtl		5.6	0.41	0.45
6mm thick Sunergy glass²	BRZ-009-06	6Sn		5.8	0.46	0.48
Breezway Innoscreen Fixed Lite Window System - Single Glazed¹
6mm thick clear glass	BRZ-008-01	6Clr		6.3	0.73	0.76
6mm thick grey tinted glass	BRZ-008-02	6Gy		6.3	0.58	0.55
6mm thick green tinted glass	BRZ-008-08	6Gn		6.3	0.52	0.64
6mm thick ever green tinted glass	BRZ-008-09	6EG		6.3	0.46	0.56
6mm thick E-Vantage clear glass²	BRZ-008-04	6EVanClr		4.7	0.55	0.58
6mm thick E-Vantage grey glass²	BRZ-008-10	6EVanGy		4.7	0.36	0.27
6mm thick EnergyTech clear glass²	BRZ-008-03	6ET		4.5	0.61	0.69
6mm thick EnergyTech grey glass²	BRZ-008-07	6ETGy		4.6	0.41	0.34
6mm thick SolTech Neutral glass²	BRZ-008-05	6SolTNtl		4.5	0.47	0.54
6mm thick Sunergy glass²	BRZ-008-06	6Sn		4.9	0.52	0.58
Breezway Altair Louvre Components in a timber frame - Single Glazed¹
6mm thick clear glass	BRZ-005-01	6Clr		4.9	0.58	0.62
6mm thick grey tinted glass	BRZ-005-02	6Gy		4.9	0.41	0.29
6mm thick super grey tinted glass	BRZ-005-06	6SoGy		4.9	0.25	0.06
6mm thick bronze tinted glass	BRZ-005-03	6Bz		4.9	0.44	0.34
6mm thick evergreen tinted glass	BRZ-005-04	6EG		4.9	0.37	0.47
6mm thick arctic blue tinted glass	BRZ-005-05	6AB		4.9	0.37	0.37
6mm thick clear low E glass²	BRZ-005-13	6LE		3.4	0.49	0.57
6mm thick Sunergy glass²	BRZ-005-14	6Sn		3.7	0.42	0.48
Breezway Dualair Altair Louvre System in the Alspec Hunter EVO Acoustic 150mm Frame – Secondary Glazed¹¹
6mm Clear / 101mm Air Gap / 6mm Clear	BRZ-010-01	6Clr/101/6Clr		3.8	0.46	0.48
6mm LowE (#2)¹⁰ / 101mm Air Gap / 6mm Clear	BRZ-010-02	6LE/101/6Clr		3.2	0.15	0.14
6mm LowE (#2)¹⁰ / 101mm Air Gap / 6mm LowE (#2)¹⁰	BRZ-010-03	6LE/101/6LE		2.9	0.11	0.05
6mm EnergyTech (#2)¹⁰ / 101mm Air Gap / 6mm Clear	BRZ-010-04	6ET/101/6Clr		3.4	0.40	0.44
6mm EVantage Clear (#2)¹⁰ / 101mm Air Gap / 6mm Clear	BRZ-010-05	6EVanClr/101/6Clr		3.4	0.37	0.38
Breezway Dualair Altair Louvre System in the Alspec McArthur EVO 150mm Centre Pocket Frame – Secondary Glazed¹¹
6mm Clear / 101mm Air Gap / 6mm Clear	BRZ-011-01	6Clr/101/6Clr		3.4	0.47	0.49
6mm LowE (#2)¹⁰ / 101mm Air Gap / 6mm Clear	BRZ-011-02	6LE/101/6Clr		2.8	0.14	0.14
6mm LowE (#2)¹⁰ / 101mm Air Gap / 6mm LowE (#2)¹⁰	BRZ-011-03	6LE/101/6LE		2.4	0.10	0.05
6mm EnergyTech (#2)¹⁰ / 101mm Air Gap / 6mm Clear	BRZ-011-04	6ET/101/6Clr		3.0	0.40	0.45
6mm EVantage Clear (#2)¹⁰ / 101mm Air Gap / 6mm Clear	BRZ-011-05	6EVClr/101/6Clr		3.0	0.37	0.39

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

WERS Ratings Table

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

Blade Type	Uw	SHGC	Tvw
Breezway Easyscreen Altair Louvre Window System - Single Glazed⁴
14mm thick Western Red Cedar timber ⁵	4.39	0.095	0
6mm thick hollow extruded aluminium⁵	6.55	0.076	0

Notes:

Results disclosed at Australian Fenestration Rating Council (AFRC) regulations.
These blades have a microscopically thin low emissivity coating that is invisible to the naked eye and improves insulation and reduces solar heat gain.
Results disclosed in Standard International Units. Results calculated to the procedures of WERS Screen Rating Methodology, 2012.
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.
As the optical properties of cedar timber and aluminium are not contained in the International Glazing Databse (IGDB), known, default properties were used.
Uw is the whole window U-value.
SHGCw is the whole windows solar heat gain co-efficient.
Tvw is the whole window visible (light) transmittance.
Star ratings calculated using Nationwide House Energy Rating Software (AccuRate) according to procedures of WERS 2008.
LowE (#2) refers to the coated surface of each glazing layer in a secondary glazing unit. 2 being the internal face of the glass.
The glazing is reported in the same orientation as it is simulated so that the outside is always on the left, inside is always on the right.

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