Windows and Doors
Let the outside in
When buying, renovating or having a home built, it is important to take windows and doors into consideration as they provide light and fresh air, and offer views that connect our interior living spaces with the great outdoors. However, ordinary windows can also represent a major source of unwanted heat gain in summer and significant heat loss in winter.
At Australian Glass Group, we offer a variety of residential and commercial glass products for doors and windows, with toughened, laminated, tinted and insulated glazed options that can meet most design parameters. Our trademark Insulglass units, can reduce heat transfer by over 50% whilst minimising the need for artificial heating and cooling, and are an essential component to a modern energy efficient home and business.
Australian Glass Group’s Laminated Glass can also provide you with the strength and stability in a glass when it is required most.
Glazing for Energy Efficiency
Windows with standard glass provide little to no insulation properties, and are the thermal weak point in buildings. In an average home, 40% of heat loss and 87% of heat gain is through inefficient glazing*.
An energy efficient window helps minimise the use of artificial heating and cooling, and makes the most of the natural climate resources. Insulglass IGU units are an essential component to minimise the need for artificial heating and cooling, reducing heat transfer by over 50%.
Utilising energy efficient glass has many benefits:
- Comfort levels: it will be naturally cooler in summer and warmer in winter, internal drafts and condensation is reduced
- Energy savings: lowered cost for conditioning spaces with artificial heat and cooling
- Less greenhouse emissions: with a lower load impact on artificial heating and cooling, there is less energy output and reduced emissions
- Noise reduction: filters out significantly more noise than standard glass
How does the glazing affect performance?
Window glazing, with high visible light transmission, provides the required luminosity to brighten the room, saving you in electrical energy and reducing greenhouse gas emissions.
Comfort Levels – Scientific research has proven that people subconsciously seek out sunlit places and enjoy spending time in natural light. Research has also proven that there are real benefits such as people are happier, healthier and calmer when associated with spending time in spaces that offer abundant natural light. The benefits of natural lighting are numerous and can affect a person’s health, the environment and energy usage. Feeling depressed? Science has shown that simply being exposed to natural light for a short period of time can prevent depression in adults as well as children and boost one’s spirits.
Energy Efficiency – 47% of the energy used in a home is for space conditioning* (lighting and temperature control). Natural light produces energy savings by allowing a homeowner to use less heat, less air conditioning and eliminates the need to use artificial light therefore minimising the greenhouse emissions of your home.
What are the key performance criteria to consider?
Light Transmission is a percentage measure on how much daylight enters a building; the higher the percentage, the higher the amount of daylight.
Glass is the only product that effects how much daylight enters. Light transmission or the proportion of the light that is transmitted by the glass is indicated by its Visible Light Transmission and higher the value the better it is to gain maximum natural sunlight into the room. Neutral glass for windows and doors would be the preferred option to achieve these results.
U Value measures air-to-air heat transmittance (loss or gain) due to thermal conductance and the difference in indoor and outdoor temperatures. As the U value decreases, so does the amount of heat that is transferred through the glazing material. The lower the U value, the better the insulation.
Solar Heat Gain Coefficient (SHGC) is the ratio of directly transmitted and absorbed solar energy that enters into the building’s interior (when compared to an open space). Solar Heat Gain includes directly transmitted solar heat and absorbed solar radiation, which is then re-radiated, conducted or converted. SHGC is expressed as a number between 0 and 1. The lower a window’s SHGC, the less solar heat it transmits. Solar gain varies according to the sun’s angle of incidence. Thus the same window can have a hugely different solar gain, depending on the angle of incidence, which is influenced by the position of the sun according to location, season and time of day, and the orientation of the glazing.
How do I know which glass to use?
There are two important questions to answer before choosing the right glass for your windows:
- What is the orientation of my windows in my home?
- What area do you live in?
Hot climates use more than 70% of their total space-conditioning energy for cooling, whereas cold climates spend less than 30%, but spend 70% on heating***. Correctly designed windows could help eliminate or reduce the need for artificial heating and cooling.
Orientation is the positioning of a building or your windows in relation to seasonal variations in the sun’s path as well as prevailing wind patterns. Good orientation can increase the energy efficiency of your home, making it more comfortable to live in and cheaper to run.
With Australian Glass Group double-glazing solutions, you can reduce energy consumption while opening up your home and office to benefits of natural light.
Principles of good orientation
Average daily solar radiation on vertical surfaces
Source – www.yourhome.gov.au
North and South Elevations
The lower angle of winter sun can limit solar access
With north and south facing elevations, the challenge is to provide insulation year round, with passive solar heat gain through the cooler winter months. A north-facing window in summer, when the sun is high in the sky, may have an angle of incidence of 8° (depending on location). In winter, the angle of incidence at midday is about 35° and the glass is exposed to a greater effective area of solar radiation. That window can transmit more solar heat in winter than in summer.
Australian Glass Group recommends: low U-Value and High Solar Heat Gain Co-efficient, with the use of eaves or blinds on the northern elevation for summer solar protection.
For Southern States
Tailored to the specific conditions of the southern states, we need to achieve passive solar heat gain through winter and insulation all year round.
Australian Glass Group recommends: low U-Value and High Solar Heat Gain Co-efficient.
With west facing windows, we need to achieve protection from solar heat gain and insulation all year round. A west-facing window on a summer’s afternoon has an angle of incidence from near 0° up to 30° with a large effective area of solar radiation. A north-facing window, in summer, has a high angle of incidence and a low effective area of solar radiation, so can transmit less heat than a west-facing one.
Australian Glass Group solution: low U-Value and low Solar Heat Gain Co-efficient.
NOTE: The SHGC declared by glazing manufacturers is always calculated as having a 0° angle of incidence, i.e. the maximum solar heat gain.
Source – www.yourhome.gov.au
Please contact us for further information.
Insulated Glass Solution (IGU)
An insulated glass unit (IGU) more commonly known as Double Glazing is a combination of double or triple glass panes separated by a vacuum or gas filled space to reduce heat transfer across a part of the building envelope into a single window system. This adds thermal resistance reduces the amount of heat escaping in winter and keeps your home at a more comfortable temperature.
Australian Glass Group recommends following IGU products for windows and doors:
Laminated Glass solution