What to look for when buying double glazing

Quality windows have features that improve living conditions and reduce heating and lighting costs. Let's find out what energy efficiency is and what technical features affect it, what noise insulation is and what its performance is, and what impact resistance is and how it affects your safety.

The window construction also includes additional options to consider when choosing and purchasing, as well as configurations on which light exposure and ventilation depend. Countries such as Australia have a changeable climate, so double glazed windows with excellent performance will be an indispensable element in your home improvement.

Generally speaking, to the average person, a window is just a glazed frame. Digging deeper, you will realize that it is a multi-component construction, in which each element is responsible for certain performance indicators. It is the double glazed window that provides reliable protection against noise, prevents heat loss, condensation, drafts and burglary. “My home is my castle”, and in many ways this phrase has a lot to do with windows.

Double glazing claims: how effective is it?

Single glazing is chosen when there is no question about the safety of property, noise protection and other qualities. Therefore, it is not necessary to talk about the benefits of double glazing, but we will list them here:

  • Energy efficiency. Double glazing is high-strength glazing with a protective coating that minimizes heat loss and the air chamber is filled with a gas that insulates heat.
  • Noise insulation. Noise protection is ensured by the same gas inside the chamber which prevents noise from penetrating and spreading, as well as by the low-emission (Low-E) coating.
  • Protection against harmful radiations is also ensured by a low-emission (Low-E) coating, which has a low radiant absorption coefficient.
  • Robustness and burglary protection. Window double glazing profile made of high-quality raw materials, of optimal installation width, reinforced all around.
  • Fittings. The profile is equipped with fittings around the perimeter of the double glazed window, responsible for reliable opening/closing, as well as keeping the correct geometry in different positions of the sashes.
  • Tightness. Tightness is ensured by a gasket whose elasticity is long-lasting, which contributes to maintaining this quality.
  • Impeccable design. The double glazed windows are produced according to the latest trends in design, so any architectural solutions will be appropriately supplemented with stylish windows.
  • Wide range of glazing. Glazing variants are available in different compositions, manufacturing and processing technologies.
  • Available in many sizes and not limited to standard sizes. We accept individual orders.

Single glazing does not have the same characteristics, so it is cheaper and the area of application is much narrower.

Will getting double glazing reduce my energy bills?

The Australian Energy Market Commission is a respected Australian energy efficiency organization and they indicate that double glazed windows reduce heating costs by between 115$ and 120$. 67% of homeowners said double glazed windows do save money.

Today’s manufacturing technology aims to ensure that living conditions are as comfortable as possible and that the elements that create this comfort also carry money savings functions. So what contributes to the energy efficiency of double glazed windows? Today it is Low-E glass that has proven to be effective in practice. Two types of initial coating are used in the production process:

  • Passive Low-E (Hard-Coat) coatings using pyrolytic films, which act as an energy insulator resulting in energy retention, and when in contact with the double glazing during the hot bonding process, this coating creates a strong bond. The glass is thus made strong and energy efficient;
  • Solar Control Low-E (Soft-Coat) coatings. A magnetron coating is used which is obtained by atomizing tiny metal particles. This creates an energy field that traps heat and reverses it back into the room. This phenomenon is called interference, in other words superposition.

Therefore, the claim that double glazing saves money is proven in practice.

What are energy ratings for double glazing?

The heat transfer resistance is a key characteristic of translucent structures, such as double glazed windows. We used to call it energy efficiency. It is, in turn, subject to a certain classification. Let’s understand what thermal transmittance resistance is. It is a value that demonstrates the ability of the structure to resist the propagation of the transverse heat flow. That is, an energy efficient window creates a kind of barrier and reduces the penetration of heat to the outside to a minimum. The higher the thermal transmittance of the construction, the better its thermal and acoustic insulation properties.

The energy rating classifications follow the same pattern as for electrical appliances, which have a specific energy label. A++ is the best energy efficiency rating; E is the worst, respectively. This information is not made up by manufacturers. The Window Energy Rating Scheme (WERS) is substantiated by scientific research and accredited by the Australian Fenestration Rating Council (AFRC). The scheme is based on this organization’s protocols and procedures at the time of assessment, including double glazing of windows and doors. AFRC compliance with the National Building Code (NCC) indicates that the windows are certified and can be used as intended.


The heat transfer coefficient, better known as the U-value, determines how quickly, or slowly, heat is transferred through a construction. In double glazing in particular, this speed is divided by the temperature difference in the glass itself.  A low U-value is an excellent value, as it indicates the high thermal insulation qualities of the construction. However, it should be noted that the heat loss depends on the quality of workmanship and installation also. It is the professionalism and experience of the installers, who perform a good sealing with elimination of gaps and thermal bridges, that is important here. Otherwise the heat transfer coefficient will be several times higher. The U-value is calculated by finding the inverse of the thermal transmittance of double glazed windows. Both internal and external surfaces are taken into account.

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Can double glazing reduce noise and soundproofing?

Of course double glazing is an excellent noise insulation element. It consists of sound absorbing glass panes that are hermetically sealed together in a profile. The space between them is filled with an inert gas, which is a sound absorbing element. If the space is filled with air, then the soundproofing will be lower; accordingly, a double-glazed window will cost less. The glass itself has coatings that also help absorb noise. It can be low-emission coatings, laminated coatings, magnetron coatings. Multifunctional glass, for example, combines different production technologies and therefore performs a number of additional functions.

Will double glazing make my home more secure?

Windows with double glazing can be manufactured with the following types of glass: triple glazing; tempered glass with increased impact resistance; impact-resistant, reinforced glass; impact-resistant, laminated glass. If you live in an unsafe region, it certainly makes sense to consider double glazing with the above-mentioned panes. In addition to increasing safety and security against intrusion, such elements are also energy-efficient and noise-absorbing.

Making wooden windows secure

Wooden casement windows are even more secure with locking latches which fasten the window and the frame together. It is then impossible for an intruder to force open a double glazed window. For window constructions in which the glazing is fitted flush to the frame, we recommend using mortise locks with a key mechanism. They bear a specific standard mark that is the specification for increased security.

Securing uPVC windows

Plastic windows are fitted with hardware that is also a multi-point locking system. This is a multi-point mechanism, which acts by turning, engaging several bolts with a plate. It is thus impossible to open the window and increases the window’s security.

Making sash windows secure

Sash limiters also securely fix the window in one position without the possibility of further forced opening. These stoppers prevent the window from being opened upwards, they stop it in place, and if the window is opened for ventilation, they keep it in place.

What double glazing extras do I need?

The overall design of a double glazing window looks seamless with all its elements. On top of that, a unique design solution will make the exterior and interior look even more stylish. The right fittings, configuration as well as colour will contribute to this.

Colour options

Double glazed windows can be available in standard shades, as well as more unique colour options. Oak or hardwood laminations may be most appropriate for classic furnishing styles, but for modern designs you can pick from the RAL palette.


Not only do the fittings play a significant role in terms of security, they also play a significant role in the appearance of the window. They can be selected according to the type of furniture and the decor of the window area.

Decorative windows

The options for selecting double-glazed windows also include decorations. The aesthetics depend not only on the right configuration and colour, but also on the type of glass, which may be textured, patterned, darkened (convenient for interior doors or windows), decorated or bevelled, and also fitted with a grille that divides the glass into several panels. Double glazed windows come in many different shapes, such as colonial, Berlin glass, mezzanine, round, rectangular and other variants. An expert will help you make the best choice.

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How do I choose a double glazed window?

As mentioned, double glazed windows are available in a range of configurations, types of glazing, and sizes. In addition to the standard designs, you can also order a project for a non-standard size and type of window. For a start, it is worth taking into account what kind of room the glazing is required, what are the architectural features of the window opening, and what are the characteristics of the furnishings. The latter should be taken into account to ensure the window blends in seamlessly with the interior. The area where the client lives is important, because it directly affects certain characteristics of the window. So if the house is located in a noisy region, you should consider a double-glazed window with high noise insulation; if the area is open and the room is exposed to the sun, it gets hot quickly, you can pay attention to tinted glass and so on. Consequently, there are preferences for the strength of the glass, its light permeability, energy efficiency and noise neutrality. As you can see, there are many characteristics of each window construction and factors that are taken into account when choosing. The individual wishes of the customer are paramount.

uPVC Windows better than wood? - write what is better

A wooden profile is usually very demanding to look after. It is certainly aesthetically pleasing, but aesthetics have to be maintained regularly. In addition, colour options for double-glazed wooden windows are limited. Nevertheless, wooden windows are versatile, fitting any style of any design. You can install a window of any thickness and weight. Wooden profile is protected against mould, mildew and moisture. Plastic profile looks modern, it is easy to look after, it has all the above characteristics of a wooden profile. The choice is a matter of individual preference.

Do you need curtains with double glazing?

Curtains are an essential attribute of every interior. They add coziness, charm and a sense of lightness. However, there are styles, including double glazed windows, which do not need to be decorated with textiles, because the aesthetics of the window are self-sufficient. For example, unique windows in a colonial style, specially stylised room do not require framing with fabric. This is true for non-residential areas such as cafés and restaurants, studios and so on. But for homes, the traditional window decoration with curtains is a must, because it is a matter of coziness.

Does double glazing have different grades?

Double glazing has different energy efficiency grades. The classification scheme is administered by the Australian Energy Efficiency Rating Council. The thermal conductivity of the window is influenced by the type of glass, the amount of air space between the panes of glass and the coating.

How can you tell quality of uPVC windows?

The quality of uPVC windows is easy to determine, firstly, by the colour of the profile. The primary raw material is white; the secondary raw material is slightly yellowed or dull. Secondly, a quality window has a good assembly width, which affects the strength and durability of the profile. Next, pay attention to the quality of the hardware and consequently the ease of operation. A quality double-glazed window opens and closes smoothly and easily, at the same time providing a good seal. This in turn depends on the quality of the gasket, which must be flexible, soft and resilient, and retain these qualities for many years to come. In addition, a soldered gasket is a sign of a poor quality double glazed window. The gasket must be removable. Again on the hardware, it is worth noting that this element is much more important than you might think, as it is the hardware that withstands the weight of the sash and the endless number of openings. Accuracy of workmanship indicates the quality of the assembly and if the window was collected not in the manufacture, but privately in someone’s garage, it will be immediately visible. The last thing you can judge the quality of a double glazed window is the insulating glass unit. It has to be completely airtight and clean from the inside and outside.

Is Thicker double glazing better?

The thickness of the glass in a double glazed window affects security above all. It is impact resistant glass that increases the level of security. The thickness of the glass also increases energy efficiency and noise insulation. But the weight of such glazing will also be an order of magnitude greater, as will the price.

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