Having decided to buy new windows, it is worth to think about the material which will be used for manufacture of the whole construction. Modern manufacturers offer a good selection of materials such as aluminium, timber and uPVC (or simply plastic). The first two can be combined to create even more functional constructions. Sometimes, people find it difficult to choose between all these options, therefore we provide an overview of these materials and their characteristic features.
Aluminium is an ideal material for glazing of shop windows (i.e. large areas for glazing), entrance halls and partitions between two rooms (for example in an office). The transparent section of the window is usually filled with traditional double or triple glazing (i.e. two or three glass panes), however it can be also filled with semi-transparent or nontransparent material, also known as a sandwich (aluminium or plastic). The aluminium profile is divided into two groups: “warm” and “cold”. Since aluminium is a good thermal conductor, outdoor glazing is usually performed with the “warm” aluminium (i.e. aluminium profile with a thermal separation that can be described as a thermal insulating insertion made of a special material that is fitted between the inner and outer parts of the profile). Warm aluminium windows are often installed in offices and other administrative buildings. “Cold” aluminium is used for manufacture of office partition walls and other constructions that are used only inside the building. All aluminium constructions are reliable, durable and resistant to environmental impacts.
uPVC windows are most frequently used for glazing of living areas such as apartments, cottages and other types of houses. Like “warm” aluminium, uPVC profiles are very good heat insulators that can be used for manufacture of office partition walls and glazing of hall entrances. However, uPVC constructions place strict limitations on the area that can be actually glazed. Regardless of all apparent advantages, aluminium is very rarely used for glazing of living areas, since the cost of “warm” aluminium constructions is much higher than those made of unplasticized Polyvinyl Chloride (uPVC). This is the main reason that explains the popularity and great demand for uPVC windows among ordinary house owners.
uPVC windows that are manufactured according to all technological requirements and instructions on modern high-quality equipment will definitely serve you for a long time. uPVC windows are not affected by impacts of external environment.
Wooden windows are most frequently used for glazing of apartments and countryside houses. The cost of such windows is considerably higher in comparison to uPVC and aluminium windows, because raw wood requires a lot of processing before it can used for manufacture of wooden profiles. All production stages include complex procedures like protection coating from insects and environmental negative effects, however the end result is certainly well worth its money.
Now, let us talk about advertisements.
Inexperienced customers very often become targets of dishonest advertisers and agitators that want to sell you their products. If you look closely, you can notice that they use a lot of funny clichés that have already become some sort of myths. Here are some of the most common:
Windows do not let cold air get inside your apartment.
Actually, ANY window lets out more heat than ANY wall. This means, that the ideal house with most heat saving efficiency would be built without windows at all. Would you like to live in such a lovely house? We seriously doubt that. Windows and doors (i.e. any openings in your walls) will aalways make up to 80% of all heat losses. There are no windows or doors that would totally prevent heat leaks in your house. However, good modern windows will save twice as much heat inside your house than old ordinary wooden windows. People often say, that uPVC windows often accumulate condensed water inside their glass units. There is nothing bad in this. It is just physics. If you cook soup for a long time with your windows closed, you will notice condensed water vapor not just on your windows, but on your walls as well. Modern windows have a very efficient system of sealing that prevents air drafts. This system also has some side effects. For example, you will need to air your room to reduce the level of humidity.
Windows suppress all street noises.
Firstly, not all windows have this feature and, secondly, the degree of suppression is very often exaggerated. For example, low-frequency noises produced by street trams, rock drills or highway traffic can be considerably blocked by right glass units, nonetheless the noises will still be heard inside the building.
High-frequency noises can be better blocked. If talking from a subjective point of view without any numbers, the noise will not disappear completely, however you can soon realize that you merely hear it. Still, if there is a high-speed motorway outside of your building, it is worth to install triple glazed windows with glasses of different thickness, for example 4 mm + 6mm + 4mm. This will give additional noise suppressing effect due to partial reduction of resonance. Apart from this, it might be a good idea to divide a large window into several smaller parts, since big glasses are more prone to resonance than small ones. Additionally, it is necessary to keep in mind that once you open the window the whole soundproofing effect will disappear, therefore if you really need quietness, you should think about some air conditioning systems that would keep your house fresh even if your windows are always closed.
There is a vacuum inside a glass unit.
The term “vacuum glass unit” is not quite correct. If there was a vacuum inside your uPVC window, then the pressure would crash the glasses inwards. In reality, the space between glasses of all uPVC windows is rarefied in order make those frames stick better to each other. However, this is not vacuum in its usual sense.
Thick triple glazed window unit is the best.
This is not always the case. There are several types of thermal exchange such as radiation exchange, convection exchange and conductivity exchange. The simplest one is solar radiation exchange. In order to make things clear, let us give an example. If you grab the metal handle of your frying pan without the oven mitt you will get a burn even though it is the pan that is heated by the flame and not the handle. Convection thermal exchange is connected to the transfer of heat with air (warm air moves upwards, while cold air moves downwards). In this case the air goes up along the inner (warm) glass and the empty space is then filled with cold air that goes down along the outer (cold) glass. In this way, we have constant circulation of cold and warm air inside the glass unit that helps to transfer heat outside and cold inside. This type of heat exchange is the most wasteful since the rate heat loss is enormously high. Narrow space between the glasses helps prevent the above mentioned circulation. Thus we need to care only about radiation and air conductivity exchanges. Now it becomes clear that the space between two glasses of the uPVC window is very carefully measured and has ideal ratios. Increase of space will inevitably lead to worsening of thermal characteristics of the whole uPVC construction.
Our experience shows that triple glazed windows are one of the best solutions for Melbourne due to their price-quality ratio. In order to enhance the insulating properties, standard glasses can be substituted for the so-called energy saving K-glasses that can reflect thermal emissions back into the house.
Prices for 1m2 of uPVC windows are unreasonably high.
It has been well said that there is no such thing as free lunch. This saying is very meaningful since this principle applies not only to your food but also to any other aspect of your life. If you have decided to change your windows, be ready to open your wallet wide. You should understand that modern uPVC windows cannot be cheaper than outdated wooden windows made by some shady firm. The prices for uPVC windows are almost the same throughout all Australia. If somebody offers you to install new windows for a ridiculous price, you should think twice before accepting such offers. Do not make your choice only because of some abstract sums. Do not be lazy to measure your windows with a simple tape, think over the configuration and layout, amount and sizes of the shutters, frames and other components. Make a call to a specialized company and let them do the calculations (Keep in mind that some tricky business owners try to cheat their customers by giving the total price without the goods and services tax). Do not forget to specify the full price you will have to pay for the delivery and installation of your new windows and other necessary details such as window sills, drip edges, transitional profiles etc.
The thicker the profile of your uPVC window and the more chambers it has, the better.
It is pointless to make your profile thicker and more complex than it should be, since its resistance to heat transfer is twice as large as that in a glass unit. If your window gets frozen in winter, then the frost will definitely stick to the glass and not to the window profile. You should rest assured that Australian winters are not cold enough to harm uPVC profiles in any way. Therefore, throw away your thoughts about all possible “construction peculiarities” and “technological novelties”. Profiles consisting of three, four or even five chambers will not make the difference and will not give additional insulation. The profile can consist even of ten chambers with ten contour rubber sealants, but this is just not necessary. No serious manufacturer will turn to such cheap tricks in order to attract more customers. The standard and most optimal scheme is a three-chamber profile, two or three sealants and a triple-glazed glass unit. All uPVC windows from the most well-known manufacturers are made in this way. Do not believe the “managers” of some firms who claim that either REHAU, VEKA, PROPLEX, KBE or INTERTEC is the best company. They are all equally good, so make your choice and enjoy the best products that modern window market can offer.
uPVC is ecologically unsafe.
We do not want to offend anyone, but such claims often come from people who are out of subject. They are based not on personal experience, but rather on some outdated prejudices.
Indeed, some decades ago people used lead as a stabilizer during production of plastic windows. Later, this element was substituted with other materials, however this was done not only because of ecological hazard (although the amount of lead was within the allowed limits), but mainly due to emergence of cheaper and more efficient stabilizers. Emission of chlorine (Cl) is not supported by any scientific tests at all. Chlorine is present in many natural compounds like NaCl (table salt), however this fact does not scare anyone. Neither we refuse to buy PVC electric kettles that are exposed to boiling temperatures which exceed the temperature of windows on a hot day. Modern uPVC windows do not burn. In fact, in cases of fire, high-quality uPVC windows can help to extinguish it. We all know that if window glasses break, the fresh air makes the fire more intense. So, even if the first glass gets broken due to great temperature difference, the second will allow to hold the fire until the fire brigade puts it out completely. It is also possible to install special glazing which can resist extremely high temperatures to enhance your protection.