Double-Glazing vs Triple-Glazing

Windows play a significant role in energy efficiency and cost savings as they can be a major source of unwanted heat loss. The type of glazing affects the amount of solar energy transmitted through a window. The better the glazing insulation, the less likely heat will be transferred from the interior to the exterior, and vice versa. We take a look at the difference between double glazing and triple glazing, costs and benefits, to help you decide if you need that extra layer of glass.

What is Glazing?

Glazing refers to the glass that is installed in the window frame. Most homes in Australia were originally built with single panes of glass, known as single-glazed windows. Windows with two panes of glass, known as double-glazed, or three panes of glass, known as triple-glazed are becoming essential features in the pursuit of energy efficient homes that meet the government’s 7 star rating for energy efficient building standards.

Differences Between Double-Glazing & Triple-Glazing

The difference between double-glazing and triple-glazing is the number of panes of glass. A double-glazed window has two panes of glass, while a triple-glazed window has three. Both types of glazing are more energy efficient than traditional single-glazed windows. However, there are a few differences which may influence you choosing double-glazing or triple. We look at the differences between the two, benefits and costs to get a clearer picture on glazing choices.

Double-Glazing

Double glazing refers to two panes of glass in a window frame, with a space between them that is usually filled with a gas like Argon or Krypton. Double-glazed windows provide extra insulation and soundproofing because of the gap that is sealed with a gas vacuum, and acts as a break between the two layers of glass. The result is less heat transfer, more energy efficiency and noise reduction.

Double-glazed windows can be installed in various window frames but are best suited to uPVC frames. uPVC provides almost identical benefits to double-glazing. It is unplasticised polyvinyl chloride, a type of hard plastic often used as a substitute for painted windows and the preferred material when installing double-glazed windows.

Benefits of Double-Glazing

• Reduced heat loss: Double-glazed windows can reduce heat loss by almost 30% compared to single-glazed windows. The thickness from two panes of glass makes the window stronger and more protected from the outside. The double-glazing also traps air between the panes which adds to the insulating effect. When you combine double-glazed windows with uPVC frames, there is an additional increase in insulation performance compared to alternative metal or wooden frames.
• Energy efficiency: As double-glazed windows reduce heat loss in winter and heat gain in summer, they are energy efficient. This means that they use less energy to perform the same task. Energy efficiency can be rated by a scheme called WERS (Window Energy Rating Scheme). This rating indicates how much energy is being saved by having double-glazed windows and windows are rated for both heating and cooling.
• Reduce noise: Double-glazing may not be soundproofing but it is the next best thing, reducing noise by between 20 and 65 percent depending on the quality. This significant noise reduction capability is equal to an average of about 35dB. This could be even lower if windows are combined with uPVC frames.
• Prevent mould: Because double-glazed windows are strong and extra thick, they prevent moisture from entering the room, which in turn prevents mould build-up. The consistent temperature of the room that is achieved with double-glazing means there is little likelihood of water vapour or condensation that causes mould spores to develop.
• Safety and security: The fact that double-glazed windows are made from two panes of glass makes them more secure and harder to break into. Combining double-glazed windows with the durable and stable characteristics of uPVC will make them even more secure and burglar-proof.
• Less cost than triple glazing: Double-glazed windows can cost up to 50 per cent less than triple-glazed windows which is a significant difference, given triple glazed only offer 20 per cent more insulation on average.

Effectiveness of Double-Glazing

Double-glazing is an effective solution for energy efficiency, noise reduction and lowering bills. The following facts explain why:

• Double-glazing can reduce the amount of UV rays entering your home by up to 75%.
• Double-glazed windows can improve your home Energy Rating Assessment by up to 50% when properly designed and installed.
• Double-glazed windows can reduce noise by up to 40 dB.

Triple-Glazing

Triple-glazing refers to three panes of glass in the window, rather than two like double-glazing. The three panes are separated by spacers that create two insulating air gaps to help reduce heat loss and improve energy efficiency. As with double-glazed windows, the gaps are filled with gas to enhance insulation. Triple-glazed windows are not as popular as double-glazed windows in Australia. However, both can be suitable depending on things like location, building design and budget constraints.

Benefits of Triple-Glazing

• Reduced heat loss: Triple-glazing reduces heat loss even further than double-glazing. Compared to double-glazed windows, triple-glazed windows conserve heat by 20 per cent more.
• Energy efficiency: The extra pane of glass means more insulation and increased energy efficiency.
• Reduce noise: The thickness of triple glazing means that noise is reduced even more than double-glazed windows. With that extra layer of glass, noise can be reduced by up to 51dB.
• Prevent mould: It can help reduce the likelihood of condensation, preventing moisture from building up and mould from growing.
• Safety and security: The extra layer of glass provides a stronger level of protection from home invasions as the glass is harder to break through. It can also withstand strong winds and harsh weather.

Disadvantages of Triple-Glazing

Triple-glazing is more expensive than double-glazing. On average, the cost is between 30 and 50 per cent more than double-glazed windows. With the heat loss reduced by only 20 per cent more than double-glazed windows, it provides a lower return on investment. While those who install triple-glazed windows will benefit from higher energy savings, the outlay for the windows and installation is significantly higher. This will suit some customers, but may not be a cost-effective option for others.

Factors to Consider when Choosing Double-Glazing vs Triple-Glazing

One of the most important questions when choosing windows is which type to invest in. When considering whether to choose double-glazed or triple-glazed, these factors should be taken into consideration.

• Budget: Triple-glazing is 10 to 20 per cent more expensive than double-glazing.
• Climate: Only extremely cold climates really need triple-glazing. In countries like Australia, double-glazed windows are sufficient for energy efficiency and comfort.
• Noise reduction needs: If you live on a busy road, both double-glazing and triple-glazing will reduce the noise outside dramatically. With the extra layer of glass, triple-glazing will reduce it by a further 10dB compared to double-glazed windows.
• Design versatility: As double-glazing is more popular in Australia, there is more design versatility compared to triple-glazing and it can be used in every window type.
• House style: Triple-glazed windows are substantially heavier than double-glazed, so the type of house you have needs to be considered. The house needs to have strong framing materials to support the weight of the triple-glazed windows.

Is Double-Glazing Better Than Triple-Glazing?

In Australia, double-glazing is better than triple-glazing. While both are energy-efficient options that will save you money and reduce outside noise, double-glazing is a preferable sustainable option that costs less and provides ample reduction of heat loss for the Australian climate.

Trying to work out whether to install double-glazed or triple-glazed windows can be a daunting task as not many people understand the difference between the two. Our article explains everything you need to know about double-glazed and triple-glazed windows, their costs and benefits to help you decide on the right windows for your project. For further information, the team at Windows for Life are always on hand to help.