A buyers guide into the world of triple glazing.
- Everything worth knowing about windows and triple glazing! 1.1 Introduction to triple glazed windows
Windows are one of the most exposed parts of a house. They are very vulnerable towards weather and wind. The purpose of windows varies a lot, from the most basic assumptions that windows are a way of letting sunshine into houses and give the occupier a means to look out into the world to the more advance purposes such as enabling the occupier to have a lower electricity bill. These two examples are just a part of what a modern window is developed to do. Here are a few other criteria´s a modern window should meet:
Insulate against heat loss
Resist extreme changes in temperature
Have an efficient noise reduction
Keep moisture and rain outside
Create a safe environment for children
Be aesthetically beautiful and fit well into the facade
In the text above the name ”modern window” appeared. Consider what separates a modern window from a normal one? These pages while help to identify the merits of the different form of glazed windows.
A modern window today is build up by three layers of glass, hence the name triple glazing. Triple glazing is a system of sealed glazing units using 3 sheets of glass. It is the next step up from double glazing. However it can be much more than this. Triple glazing is not yet the norm in the UK, most people in Britain will only know about it from watching housing programmes as Grand Designs. In colder countries with extreme winter weather, particularly in Scandinavia and in Canada they have been a building standard for decades.
The aim of triple glazing is to provide better thermal and sound insulation than other forms of windows. It is likely that UK building regulations will specify triple glazing as standard on new buildings within 5 years.
It is possible to go beyond triple glazing, having four or more panes of glass. However the units would get increasingly large, heavy and cumbersome. The incremental thermal benefit tails off rapidly, so it would offer poor value for money. In addition, light transmission and clarity of vision would noticeably be reduced.
Before buying triple glazing is it advisable to understand how it works. With the help of this site its possible to understand most aspects about how triple glazing works. From how efficient their energy performance is to how well they reduce traffic noise and other high noise sources.
2.1 The structure of triple glazing There is much more to triple glazing than just assembling 3 sheets of glass.
To maximize the insulating effect the optimum gap required between the panes is about 16mm. Too close together results in radiant heat loss, too far apart leads to creation of gas currents which causes convection current heat losses.
The gap should be filled with inert gas as this provides greater insulation than air due to low thermal conductivity. Argon is commonly used as it is cheap to produce and is about 1/3 better as an insulator than air. Krypton is used in the highest specification units as it has double the insulation property of air.
At least the inner, and ideally also the middle pane should have a low emissivity coating. Also known as K glass, this has a metallic coating on the inner side of the unit. The effect of the coating is to allow short wave length sunlight to enter a room and heat it and to achieve a large reflection on the long wave length sunlight, thus the window minimizes the existing heat loss that exists around all windows. The low emissivity coating is normally made up of a thin layer of metal, preferably indium-oxide, rod-oxide, copper, silver or gold. The low emissivity coating is normally applied straight onto the glass or in certain cases onto a plastic film that then in turn is attached to the glass. Depending on what metal the coating is made of the triple glazing gets different characteristics.
Most glazed units use glass panes of the same thickness, but this is not a necessary requirement. To reduce shear effects on the sealed glaze unit, most standard production units are restricted to a thickness difference of 1mm between consecutive panes.
The key to the structural integrity of the sealed units is the frame. This has to be rigid because any twisting in the unit will shatter the glass.
Early double glazing in the UK used aluminum frames, which are both light and strong. However as a metal, it conducts heat out, so undermines the thermal efficiency of the units. Most double glazing units are now uPVC, generally white, with aluminum internal support, which has better insulation properties.
Triple glazing is usually found with wooden frames, because of its great insulation properties, and relative cheapness in the cold climate countries.
The panes of glass are separated by spacers. Originally metal spacers were employed, but these were effectively cold bridges and reduced the efficiency of the sealed unit. There was also an increased risk of condensation. Now the spacers are usually made from glass fibre.
2.2 Illustrated picture of the structure behind triple glazed windows.
A triple glazed window is so much more that just a few layers of glass and a frame. Below is a detailed description of what a typical triple glazed window looks like. This will make it easier in understanding the terminology of triple glazing.
2.2.1 Bågbottenstycke
Den understa vågräta delen av fönsterbågen.
2.2.2 Bågöverstycke
Den översta vågräta delen av fönsterbågen.
2.2.3 Fönsterbåge
Delen där fönsterglaset sitter.
2.2.4 Fönsterhake
Metallkrok som låser fast fönsterbågen i stängt läge.
2.2.5 Isolerglas
Två eller flera glas som är hermetiskt tillslutna.
Mellanrummet mellan glasen innehåller torr luft eller gas.
2.2.6 Kopplat fönster
Ett fönster med bågar i två delar som går att dela
(alltså fyra sidor att putsa).
2.2.7 Karm
Delen som sitter fast i väggen.
2.2.8 Karmfast fönster
Ett fönster som inte går att öppna.
2.2.9 Karmyttermått
Karmens exakta yttermått, bredden anges alltid först.
Exempel: 985 x 1185 mm = ett modulmått på (10x12).
2.2.10 Karmunderstycke
Den nedersta vågräta delen av fönsterkarmen.
2.2.11 Mittpost
Den lodräta mittstolpen mellan två fönsterbågar.
2.2.12 Profilering
Fönstrets raka kanter har profilerats för en snyggare design.
2.2.13 Spanjolett
Anordning som låser fönsterbågen i karmen.
2.2.14 Spröjs
Tunna lister som delar in fönsterrutan i mindre fält.
Det finns fast och löstagbar spröjs.
2.2.15 Sideswingfönster
Betyder att fönstret kan snurra vertikalt runt sin egen axel.
2.2.16 Tvåglas eller treglas
Antalet glasskikt i varje fönsterbåge. Treglas spar mer
energi.
2.2.17 Tvärpost
Den vågräta mittstolpen mellan två fönsterbågar.
2.2.18 Vridfönster
Ett fönster som öppnas genom att vridas runt 180° utanför
fasaden.
3.1 The energy performance
3.2 An Introduction to energy aspect of windows and triple glazing.
What is the big difference between a energy efficient window and a ”normal” window?
There are some big differences between the various types of windows on the market today. A good window is suppose to reduce the heat during the summer and enhance the heat during the winter. This is one of the reasons why its so important to select windows carefully. To invest money on new triple glazed windows will defiantly result in a higher effective yield than the most lucrative interest rate on the market today. As if that was not enough it will also contribute to a healthier environment since every saved kilowatt hour reduces the carbon dioxide emission by one kilo.
Most white goods such as washing machines, refrigerators and dishwashers now carry detailed energy consumption and efficiency ratings. Enabling consumer to make an informed choice regarding energy efficient machines. This has been reinforced by the 2005 European Union law that requires all the devices powered by electricity to be certificated in order to improve their energy consumption and efficiency
Similar legislation could soon be introduced for the window market since about a third of the heat loss in a normal house is caused by poorly insulated windows. Energy is not something we can discover by the naked eye and hence factors like price and aesthetic appeal tends to be taken into consideration before the energy performance comes to purchasing windows. This results in that a large number of homes throughout out the UK and North America are wasting energy by having poorly isolated windows which in turn leads to increased heating bills. The second law of thermodynamics states:“heat does not flow spontaneously from a cold material to a hot material, but it allows heat to flow from a hot material to a cold material”. In other words heath loss occur when heat flows towards colder materials through the shell of the house. By this we refer to the floor, roof, walls and windows.
The heat loss in windows mainly occurs when the heat in a room finds its way out throughout the glass and the frame of the window. Though this is not the only way heat loss can occur throughout a window. As we mentioned in paragraph 2.1 (The Structure Of Triple Glazing) greater insulation can be provided by filling the gaps between the layers of glass with gas this creates less thermal conductivity.
We have yet to wait for a regulations defining an energy performance standard that would be very helpful within the market for windows. Window manufacturers throughout out Scandinavia have started a project together with the authorities in order to create a standard for energy performance. The purpose of this project is to help consumers to chose energy efficient windows, reducing emissions and reducing the cost of heating bills. To find the authorities and the manufactures, all of whom produce triple glazing, by navigating to the link archive.
The UK Government's Code for Sustainable Homes points the way forward in Britain. The aim is to produce zero net carbon emissions from new homes from 2016, and the code specifies a target for windows of 0.8 U. The U-value is the standard measuring system for energy performance. In order to give more of an insight into the terminology that exist around windows and energy performance a short glossary is given below. To sum this paragraph up triple glazing is the way ahead.
3.2.1 Short glossary
When thinking about buying triple glazing knowing the following items can be of great use. Please notice that a few things will be explained more thoroughly in later paragraphs.
U-Value
The U-value is the measurement of heat efficiency of a window. This will be explained in detailed in paragraph 3.2.4
Daylight transmittance
This is a measurement that tells us the percentage of daylight that is enabled to pass throughout a window.
Solar energy transmittance
The measurement resembles the daylight transmittance measure but the solar energy transmittance tells how much of the daylight heat that can pass throughout a window. Solar energy is of course free energy so a high solar energy transmittance means a higher amount of free energy. For normal residential houses a recommended window should provide a solar energy transmittance over 50%. One important thing that should be mentioned is that with a large window area facing towards south it might be advisable to chose a window with lower solar energy transmittance to prevent the heat from being becoming uncomfortable.
3.2.4 U-value and examples how heat loss can occur In this paragraph the term U-Value will be evolved. U-Value is today the standard measuring system for energy performance, with lower scores indicating greater efficiency. U-Value can be defined as a building´s (or a part of a building´s) thermal resistance. It is
indicated in units of watts per squared meters per Degree Kelvin [or W/m²K]. Note that Kelvin is used as the scale of temperature difference, but this is numerically equal to Celsius. So to break this down in easy terms the U-value tells us how great the heat loss is for a part of a building or the whole building in itself.
The heat losses through a building´s windows makes up a massive part of the total energy/electricity bill for a standard household, in a normal house the costs for this particular heat loss can reach around 15-20% of the total bill and as described earlier it can even reach up to a stunning 33% depending on the circumstances.
A U-value is calculated on a windows whole construction, including the frame and the amount of glass layers being used. However this is not all, as we described in paragraph 2.1 there are other factors that can help a window to decrease its U-Value. Such a gas between the layers of glass and a low emissivity coating.
A low emissivity coating on glass drastic changes its characteristics. Preferably what it needs to achieve is to allow short wave length sunlight to enter a room and heat it and to achieve a large reflection on the long wave length sunlight, thus the window minimizes the existing heat loss that exists around all windows. To read more about low emissivity coating and gas go to paragraph 2.1 (The structure of triple glazing).
The following example shows how the U-value fluctuates when adding one or two low emissivity coatings and gas, to double glazed and triple glazed windows.
Approximated
U-values
W/(m²K)
Normal glass
Window with one low emissivity coating
Window with two low emissivity coatings
+ air
+ gas
+ air
+ gas
Double glazing
2,5
1,8
1,6
1,8
1,6
Triple glazing
2,0
1,5
1,3
1,2
1,0
Windows that have low U-values has a higher temperature on the inner layers of glass compared to windows with high U-values. This means that the risk for down draught decreases and the comfort on the inside increases.
In a room with a high humidity the risk of getting condensation will decrease significantly with triple glazing. To read more about condensation navigate to paragraph 3.3. Most triple glazing manufacturers produce windows with a U-Value of 1.3 W/(m²K) as standard though having said that there are constantly new improved products being presented. To see what type of windows that are being manufactured right now please visit our link archive and navigate through to the different manufacturers sites.
The inner layers of glass are not just affected by the U-value but also by other aspects such as the humidity inside as well as on the outside. The table below shows the temperature on the inner layer of glass, the different parameters used are: a room temperature of 20 degrees Celsius and the variable outside temperatures are -10 °C and -20 °C.
Temperature on the inner layer of glass, when the
room temperature is set to 20 °C
U-value on window
W/(m²K)
Outside temperature
-10 °C
-20 °C
3,0
8,5
4,5
2,0
12,0
9,5
1,3
15,0
13,0
1,0
16,0
15,0
These temperatures are showing how efficient triple glazing can be. Therefore the way to decrease energy and electricity bills is to switch to triple glazed windows. The decrease in energy usage is of course depending on how much the U-Value improves. As mentioned earlier the temperature plays a big roll in the energy game. This means that depending on the area the results may differ. For instance up north in the colder climates the efficiency of switching to triple glazing will be more apparent than in warmer climates down south. As an example take a small house house with a complete window area of 16m². By changing the existing windows with the U-value of 2,5 to new triple glazed windows with the U-value 1,3 there will be a big change in the energy/electricity bill. Where this house located in Canada or Scandinavia the saving could be up to 3000kWh per year but where this house in the UK the saving would be more towards 1500kWh per year.
For easier understanding the following facts may be helpful:
One square meter of a standard single glazed window will transmit about 5.6 watts of energy for each degree difference either side of the window or a U-Value of 5.6. A double glazed window will be significantly better with a U-value of 1.8 i.e. Only transmitting 1.8 watts of energy in similar conditions and a triple glazed window will have a U-value of as low as 0,8, being over twice as effective compared to a double glazed window. It should be mentioned that some manufacturers are already producing triple glazed units at 0.5 U.
Older double glazing would get a value of 3, but this has been improving over the years with technical advances. In using optimum spacing between the panes, inert gas rather than air and low-emissivity coatings, there has been major progress. Current UK Building Regulations specify a maximum U-value of 1.8, which is as good as air filled units can achieve. This is equivalent to that achieved by nineteen eighties triple glazing.
As a comparison the current U-value required for walls in the UK is just 0.3!
The UK Government's Code for Sustainable Homes points the way forward in Britain. The aim is to produce zero carbon new homes from 2016, and the code specifies a target for windows of 0.8 U. So triple glazing is the way ahead. 3.2.5 Daylight
Daylight or sunshine plays a big role in peoples fitness. If people do not get enough sunshine the immune defenses will start to decrease and the body will not produce enough vitamin D. Sunshine is also important in the way objects, people and our surrounding are perceived. If this was not enough, sunshine also affects peoples circadian rhythm and the ability to concentrate for long periods. So to sum up sunshine is a vital in order for humans to work properly.
One of the main purposes of a window is to transmit sunlight into a building. The amount of sunlight that can enter a building depends on a few different factors, these include:
The area of the windows
The positioning of the windows
The number of layers of glass that are installed in the windows
If the windows are equipped with low emissivity coating.
The size and shape of the rooms
The surrounding outside the window.
To achieve the optimal amount of sunshine in a room the total area of the windows should cover 10-12% of the total room area. A room the size of 20 m² hence needs a window area of 2-2.4 m².
Most of the sunshine passes through the glass but a little is absorbed by the glass and a similar small amount is reflected. This causes a reduction in the amount of sunshine that is allowed to pass through and this happens with all layers of glass, meaning that triple glazing has a disadvantage against double glazing. A normal double glazed window lets through up to 80% of the sunshine compared to the triple glazing that normally lets through 75%. If the windows are equipped with low emissivity coating this numbers are maybe reduced by up to 10%. The recommended amount of sunshine that should be let in into our houses is 63%. So triple glazing still remains a very good alternative.
The part of the sunshine that gets absorbed in the glass heats it up which results in some secondary heat since this heat gets disposed either outwards or inwards. Secondary heating is normally used as added heat to a building. The amount of heat that can enter a building depends on very much the same things as sunshine. The recommended amount of heat that should be let through is around 52%.
The table below shows how the different types of windows let through different amount of heat and sunshine. Please note that these values are not 100% accurate since they wont take gas or other various types of coating into consideration.
Window
Sunshine (%)
Heat (%)
Double glazing with:
Plain glass
80
75
One layer of low emissivity coating
75
70
Insulating cover and one layer of low emissivity coating.
75
65
Triple glazing with:
Plain glass
75
70
One layer of low emissivity coating
70
60
Insulating cover and one layer of low emissivity coating.
70
60
Insulating cover and two layers of low emissivity coating.
65
50
3.2.5.1 Luminosity
Daylight can be measured in luminosity this is a value of the brightness both inside and outside a room. Luminosity can be expressed in LUX which is explained as follows
Luminosity can also be expressed in LUX which in advance terms can be explained as followed: (Please skip the following few sentences if you feel tired or don't want to listen to technical mumbo jumbo, this is only for the very interested.) LUX is in short a derived unit based on lumen and lumen in turn is a derived unit based on Candela. One LUX is equal to one lumen per square meter, where 4π lumens is the total luminous flux of a light source of one candela of luminous intensity. In other words: 1 LUX = 1 lumen·m-2 = 1 candela·sr·m–2.
To make the relation between daylight and LUX a bit more comprehensible we below introduce a table with both measurements. Please note that these measurements have been calculate on the base that the luminosity outside is set between 3000-8000 LUX. Brightness %
Luminous emittance %
0,5-1,0
40
1,0-2,5
80
2,5-5,0
150
5,0-10,0
300
There are many different recommendations regarding how high the luminosity should be in different rooms, bathrooms and kitchen should normally have around 500 LUX where as normal rooms have lower recommendations around 300 LUX.
The shape of the windows frame has a great importance for how the daylight in a room will be presented. Old school widows are generally painted white on the inside and this was done in order to achieve the best amount of daylight. Newer windows tend to have a sharper outline which does not transmit the daylight as well nut by shaping the corners it can give a softer presentation.
It should also be mentioned that light that entering a room from low placed windows will not be as effective as light that enters from high placed windows. This is because the direct daylight can reach further into the room if it enters from a high point. Daylight that enters close to the top of the window can be four times as effective as the daylight that enters in the lower part of the window. This means that a small high placed window can be more effective than a larger low place window. Accordingly a skylight window placed in the right direction will let in more daylight than any other regular window.
3.2.5.1 Sun blocking
During the hotter parts of the year the secondary heat that windows produce can become too intense. An illustration would be how hot a conservatory can become under a scorching sun. By using different methods of cooling this heat can be reduced, unfortunately this is often a very expensive method. A cheaper and more environmentally acceptable method is to use different types of sun blockers. This helps not only to prevent the secondary heat but also the direct heat. Sun blockers can be placed either outside, inside or between the layers of glass and their efficiency depends on where they are placed.
The best way to place sun blockers is to put them on the outside of the windows. These types can be fixed or movable and come in all different shapes e.g. awnings, sunblinds and porches. Windows sometimes have the advantage of being placed further into the facade, something that gives them automatic sun blocking from the building itself. One disadvantage with fixed sun blockers is that they do not normally cover sunshine during the whole course of the day. This however is not a problem since sunshine often is welcomed later on in the evenings. Movable sun blockers e.g. blinds and awnings often have the capability to cover the whole window if needed, these type of sun blockers should always be installed so that there exists a gap of air in between the window and the sun blocker when in use.
Sun blockers on the inside are not as effective as the outside versions. This is because the secondary heat can still exist as most of the sunshine still gets absorbed by the window. These however are the most normal types of sun blockers as curtains and venetian blinds exist in almost every household.
3.3 Condensation on windows
Condensation can appear on the outside and on the inside of the glass. With both double glazing or triple glazing there is a chance that condensation can appear between the layers of glass. The reason why condensation appears is because a high humidity comes in contact with a cold surface. In this paragraph we will clear up the term condensation and the different types that are related to a multi-layered window
3.3.1 Condensation on the outside of the glass As mentioned earlier energy efficient windows prevent heat loss, this results in that the outer glass becomes much colder than the outer glass in windows with a higher U-value (in other words windows with less insulation capabilities). If the outer glass temperature sinks below the temperature in the air at the same time the humidity outside is high condense will appear on the outer glass. If the temperature on the glass sinks below 0°C there is even a risk that ice crystals may appear. This often happens during the autumn when the sky is clear and the humidity is high.
This type of condense is nothing to be worried about, it is actually just a sign that the window has good insulation capabilities. Condensation often disappears during the early morning hours as the air starts to get warmer.
A research regarding the climate was recently carried out by the Swedish department for testing and research. The study was carried out in Stockholm and showed how the phenomena condensation often appears during August, September and October. The condensation was most active during the earlier hours of the day and quickly reduced after 6 am.
3.3.2 Condense on the inside of the glass
Old windows sometimes gets condense on the inner glass, this is something that normally occurs during the colder parts of the year. The main reason behind this is that the window has poor insulation capabilities, as a result it makes the inner glass a lot colder than the room itself. When the hot air inside the room hits the cold glass the condensation appear. There are many other ways that condensation on the inside can appear, it can be anything from a bad ventilation system to a really high humidity, its not uncommon that curtains prevent the air close to the window from circulation and thus condensation appears.
Condense on the inside is different from the outside version as this type of condense is actually harmful. If condense on the inside is allowed to remain for a long time the window might be permanently damaged since its not constructed to prevent moisture from the inside.
3.3.3 Condensation between the layers of glass
This type of condensation can appear if hot and humid air leaks into the gaps between the layers of glass. A reason for this could be that the house has an overpressure (air pressure above that of the atmosphere) thus the air is forced into the window through cracks. A working ventilation system should normally take care of the overpressure. Air can only get forced through cracks if the window has been not been sealed properly between the frame and the casement. Another common reason that enables air to get through is cracks made from fixings for blinds. If condensation appear in between the layers of glass it is advisable to switch to more energy efficient windows such as triple glazing.
3.4 Infrared pictures of heat loss through windows
Heat loss can occur in many ways. To increase the perception regarding heat loss the following illustration maybe helpful. The picture is from the Swedish authorities of Energy and show the heat loss poorly insulated window. Please note that this link is available in our link archive.
The pictures below has been taken with a heat camera, in between the pictures there is a scale that explain which colors that represent the different temperatures.
The left hand imagine show the room has an average temperature equivalent of 25 degrees Celsius and yet the area around the window frame it is only 17 degrees. According to the laws of thermodynamics these differences in temperature will cause air streams inside the room.(drafts). To secure this problem the windows has to mean draught proof.
In this picture the blinds are not in use, they are represented by the yellow line underneath the top of the blue frame. During cold nights energy and heat can be preserved by closing the blinds.
4.1 Sound reduction
For noise reduction there is a need for a different approach to the construction of triple glazing.
The thickness of the glass used is one of the key elements of the sound insulation. Each thickness of glass will block a different frequency, so a combination of panes of different thickness is very effective at keeping noise out. This is known as asymmetrical glazing. It should be mentioned that even the weight of the glass plays a part since the compact mass reduces sounds.
The second key element is the size of the gap between the panes. The larger the gap, the better the overall sound insulation effect. So by having a second gap, triple glazing has a clear advantage over double glazing.
The third element is the use of an acoustical resistant gas, such as sulphur hexafluoride to augment or replace the inert gas fill. This effectively reflects noise away.
If triple glazing is being considered solely for sound insulation then it would be worth considering secondary double glazing instead. This is because it will have a much greater air gap than can be achieved in triple glazing, and can achieve great noise reduction at considerably less cost. 4.2 How to improve the sound reduction
There are lots of ways to improve the existing sound reduction and noise canceling that windows provide. One simple and rather normal way is to apply draught excluder to the windows, this should be placed between the window frame and casement. It is also important to make sure that the gap between the window and the wall has been sealed properly. To reach the best possible sound reduction two layers of draught excluders can be applied.
A problem can arise with a window which is in good condition but still has bad sound reduction. It could be a good idea to add another layer of glass to the window, this would improve the sound reduction immensely. This is of course depending on the type of window that has already been fitted. If this alternative is possible then make sure to install a sheet of glass that varies in thickness from the other layers of glass. This will not only reduce noise but improve the windows U-Value as well. (See paragraph 3.2.4)
When purchasing new windows to reduce noise its advisable to make sure that the windows fit into the facade so the aesthetic beauty will be preserved. Be certain to observe local and countrywide rules and regulations regarding changes to buildings as some areas will not allow changes that effects the character of the building.
To sum up, there are a few simple criteria a sound proof window should meet.
The window should be air tight
The window should be fitted and sealed properly against the surrounding wall
Avoid installing air ventilators in the frame
Maximize the gap between the layers of glass (at least 30 mm in total)
Alternate the thickness on the different layers of glass.
5.1 Damages
There are many ways windows can get damaged, moisture is one of the more common ways. It can both come from the inside and the outside, as we described in paragraph 3.3 (Condensation). Long term condensation causes the most damages from the inside, to prevent long time see the same paragraph. Regarding the outside, rain, snow and wind cause the most damage.
Damages due to damp that comes from the outside are often caused by pelting rain and can only occur if the window and its surroundings have not been sealed properly. Example of this are the gaps between the frame and the wall or the frame and the glass. These types of damage are very scary and if it should happen replace the windows urgently.
The highest percentage of damages normally occurs in the lower part of the window and especially in windows that have been hit hard by the climate. Coastal climates often put a lot of pressure on a window in the form of sun, wind and moisture. The reason behind the damage occurring in the lower part of the window is purely because of gravity, water tends to end up in the bottom of the window and stay there.
The biggest reason behind wooden windows starting to rot is a combination of events. All these combinations have one thing in common, that the window has been exposed for moisture during a long period of time. The following four criteria must happen in order for wood to rot:
The amount of moisture in the wood exceeds 20% of the total amount of wood. In other terms 0,20 kg water/kg wood
The temperature needs to be between 4–40 °C
The wood needs to be exposed to air
Access to nourishment for the fungus (Exists in the non treated wood)
If any of these criteria above are missing the wood will not get attacked by fungus and rot. So a smart window construction will make sure that fungus can never develop and hence the wood wont rot. A great tip is to impregnate the wood with preservative so that the fungus cant exist.
6.1 Maintenance
Timber framed or wooden frame windows need to be properly maintained to prevent deteriorating resulting in the need to replace the windows. Window maintenance is everything from painting to making sure that all the individual parts are functioning properly. (For instance sealing jointing)
The need to repaint windows often depends on the construction of the window itself plus numerous other are fitted into the facade and what direction they are facing. Windows that are facing south get worn more quickly since they experience larger differences in temperature, as during the day the are exposed to the warm sun and during the night they become really cold. This variation in temperature exposes the window to the extremes of climate and therefor maintenance becomes a more vital chore.
Most window manufacturers have different recommendations on when to repaint windows, a common norm is to repaint windows after 10 years and then follow this up every seventh year. This is backed up by research which has shown that this gap of time is sufficient in order not to damage the windows. As always though, it is best to check regularly to see when the windows need repainting.
This is the normal procedure when it comes to repainting windows:
Peel and scrape of the existing paint. Make sure to carefully check the corners and the lower parts of the windows as these parts often gets worn out first.
Replace the damaged timber and wood if necessary.
Fix and replace any glass, though make sure to paint the frame before attaching the new glass!
Paint the whole window and not just a few selections.
Carefully check the appearance and if the window has been taken out of the facade make sure it is sealed properly when refitted.
A window with a timber frame covered in aluminum makes the maintenance a lot easier. Similarly for PVC and other windows made from plastic. The only thing that is needed is to check the window and clean it when dirty. Make sure to do regular check ups since their condition will become worse with time.
The following websites could be worth looking into:
HYPERLINK "http://www.articlesbase.com/.../how-to-maintain-your-windows-in-seven-easy-steps-879988.html"http://www.articlesbase.com/.../how-to-maintain-your-windows-in-seven-easy-steps-879988.html
HYPERLINK "http://www.localwin.com/julie/walls-windows"http://www.localwin.com/julie/walls-windows
6.3 Cleaning windows
To clean a window can sound like the most basic chore at first but when explained most people realize that cleaning a window is not as easy as one would think. For instance there are a few windows out on the market today that cleans themselves. These windows have a certain coating that reacts in two different ways when exposed to sunlight. First the coating breaks down the layer of dirt through a photocalystic process and then when it rains the dirt gets washed away.
This type of coating is named hydrofilt which means that it attracts water. Hydrofilt coating spreads the water over the glass surface making sure no water drops are created. In order for this process to work UV-light need to be present. If this doesn't help one might have to clean it with soaped water and a normal soft kitchen towel. Though make sure the water is not to hot.
There are many different techniques to clean windows today. Normally use water and normal washing up liquid, sometimes it can be good to add a few drops of methylated spirit to get a more efficient blend. To scrape the window preferably use a normal rubber scraper.
An alternative method that can be used is to clean a window with tepid water and a normal cloth and then later on when the window is dry use a microfiber cloth and wipe it clean. The microfiber cloth should be rinsed under cold water and then squeezed dry before using it to wipe the window. This method give less ”stripes and marks” on the window and is considered to be quicker.
Though the most common alternative is to hire someone to do the job. There are numerous places to look at if wish to hire window cleaners. Either go to The Master Guild Of Window Cleaners which is a non-profit organization founded by window cleaners, for window cleaners. The Guild is not like a normal trade association but rather a community based professional support group. This particular guild is run and maintained on a voluntary basis and the web address is: HYPERLINK "http://www.mgwc.org/"http://www.mgwc.org.
Another good place to look at can be the International Window Cleaning Organization. The International Window Cleaning Association is a non-profit trade 501(c)(6) association committed to raising the standards of professionalism within the window cleaning industry this organization can be found at the following address: HYPERLINK "http://www.iwca.org/"http://www.iwca.org/.
If living in the UK the federation of window cleaners might be the best place to look at, they are located at this address: HYPERLINK "http://www.nfmwgc.com/"http://www.nfmwgc.com/ HYPERLINK "http://www.nfmwgc.com/".
HYPERLINK "http://www.nfmwgc.com/"
Please note that all the following URL´s can be found in our link archive.
7.1 Markings and Certificates
There are many different certificates out on the market today, however the European Union has developed one system that applies over all the EEA countries, its called The CE marking system and it is an acronym for the French "Conformité Européenne".
The CE marking system is a mandatory conformity mark that exist on products placed on the single market in the EEA area (European Economic Area). The CE marking purpose is to certify that a product has met EU consumer safety, health or environmental requirements.
When using the CE marking, the legal responsible person for the product (often manufacturers), assert that the item has met the essential "Health and Safety" requirements of the relevant European Directive(s) that provide for the CE marking. This may include low voltage equipment, medical devices, toy safety or in this case windows.
Residences of the following countries can use the CE marking to see if their windows have met the mandatory requirements: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Iceland, Hungary, Ireland, Italy, Latvia, Lithuania, Lichtenstein, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom.
There are other certificates and markings for windows around the world but unfortunately none of them are international. In Scandinavia there is a project called EQ marking which stands for Energy efficient Quality Windows. This project between different window manufacturers to put a value on triple glazed windows so consumers easily can asses how energy efficient a window is. The scale runs from A-G ( See picture).
This scale is not the only requirement in order to obtain window EQ approval. To retain the EQ label the windows have to meet the following requirements:
The window needs to be air tight
The window should have at least a 10 year warranty
Instruction manual should be provided.
The window needs to be movable
The window needs to be sealed against heavy rain and wind.
The window needs to be able to open, close and turn with a resistance
If you would like to calculate how much you can save by switching your windows please feel free to visit the following web site: HYPERLINK "http://www.energifonster.nu/sv/rakna_ut_din_energibesparing.aspx"http://www.energifonster.nu/sv/rakna_ut_din_energibesparing.aspx.
8.1 Link archive 8.1.1 Suppliers
Triple glazed window suppliers are pretty thin on the ground compared to double glazing and are more often than not fitters of imported units. Here are a few we've found on our travels:
HYPERLINK "http://www.rawington.com/index.html" \n _blankRawington, specialise in wood/aluminium windows.
HYPERLINK "http://greensteps.co.uk/view/category.do?id=63" \n _blankGreen Steps, supplier of Tanums Fonster triple glazed timber framed windows from Sweden.
HYPERLINK "http://www.velfac.co.uk/Homes/Windows_1" \n _blankVelfac - Supply contemporary windows and patio doors with advanced features such as solar control, integral blinds, opaque and noise reducing glass.
HYPERLINK "http://www.dynamight-internorm.co.uk/categories.php?cat_id=4"Dynamight Internorm - Passive house triple glazed windows & patio doors.
HYPERLINK "http://www.tisu.co.uk/"http://www.tisu.co.uk/ - The midlands premier window manufacturer.
HYPERLINK "http://www.leaddesigns.co.uk/"
HYPERLINK "http://www.leaddesigns.co.uk/"http://www.leaddesigns.co.uk/ - Manufacturers of Double Glazed Sealed Units & Glass Processing Work, even specialize in triple glazing.
HYPERLINK "http://www.ecomerchant.co.uk/"http://www.ecomerchant.co.uk/ - The UK's leading environmental builder's merchant.
8.1.1 Scandinavian suppliers:
These sites could be of use if you want to special order windows or get inspiration on windows you want to purchase.
HYPERLINK "http://www.domlux.net/"www.domlux.net
HYPERLINK "http://www.elitfonster.se/"www.elitfonster.se
Product catalog:
http://www.elitfonster.se/EgnaSystem/Katalogbestallning/pdf/Elit_Allt_om_fonster.pdf
Prices (SEK):
http://www.elitfonster.se/EgnaSystem/Katalogbestallning/pdf/Konsumentprislista%202009-1.pdf
HYPERLINK "http://www.enomicfonster.se/"www.enomicfonster.se
HYPERLINK "http://www.fonsterbolaget.se/"www.fonsterbolaget.se HYPERLINK "http://www.enomicfonster.se/"
HYPERLINK "http://www.fonstergruppen.se/"www.fonstergruppen.se
HYPERLINK "http://www.nordic-house.se/"http://www.nordic-house.se/
HYPERLINK "http://www.smartafonster.se/"www.smartafonster.se
HYPERLINK "http://www.mirgruppen.se/"www.mirgruppen.se
HYPERLINK "http://www.mockfjards.se/"www.mockfjards.se
HYPERLINK "http://www.skaala.com/"www.skaala.com
HYPERLINK "http://www.SkanskaByggvaror.se/"www.SkanskaByggvaror.se
HYPERLINK "http://www.spfonster.se/"www.spfonster.se
Product catalog:
http://www.spfonster.se/images/stories/pdf/Katalog2009.pdf
Sizes and storage:
HYPERLINK "http://www.spfonster.se/images/stories/pdf/LagerOchStorleksguide.pdf"http://www.spfonster.se/images/stories/pdf/LagerOchStorleksguide.pdf
HYPERLINK "http://www.sscskelleftea.se/"www.sscskelleftea.se
Product catalog:
http://www.sscskelleftea.se/upload/Www-Externt/Broschyrer/Bestallning/Fonster_webb.pdf
HYPERLINK "http://www.tanumsfonster.se/"www.tanumsfonster.se
HYPERLINK "http://www.trarydfonster.se/"www.trarydfonster.se
HYPERLINK "http://www.velfac.se/"www.velfac.se
HYPERLINK "http://www.velux.se/"www.velux.se
HYPERLINK "http://www.westcoastwindows.se/"www.westcoastwindows.se
HYPERLINK "http://www.Wisy.se/"www.Wisy.se
8.1.2 ”Do It Yourself” sites:
HYPERLINK "http://www.homebuilding.co.uk/"http://www.homebuilding.co.uk/
HYPERLINK "http://www.articlesbase.com/.../how-to-maintain-your-windows-in-seven-easy-steps-879988.html"http://www.articlesbase.com/.../how-to-maintain-your-windows-in-seven-easy-steps-879988.html
HYPERLINK "http://www.localwin.com/julie/walls-windows"http://www.localwin.com/julie/walls-windows
HYPERLINK "http://www.diy.co.uk/"http://www.diy.co.uk
HYPERLINK "http://www.homebuilding.co.uk/"http://www.homebuilding.co.uk/
HYPERLINK "http://www.selfbuildit.co.uk/"http://www.selfbuildit.co.uk/
8.1.3 Magazines:
HYPERLINK "http://www.traditional-building.com/"http://www.traditional-building.com/
HYPERLINK "http://www.residentialarchitect.com/"http://www.residentialarchitect.com/
HYPERLINK "http://www.edcmag.com/"http://www.edcmag.com/
HYPERLINK "http://www.designbuild-network.com/"http://www.designbuild-network.com/
8.1.4 Other
HYPERLINK "http://www.energifonster.nu/sv/rakna_ut_din_energibesparing.aspx"http://www.energifonster.nu/sv/rakna_ut_din_energibesparing.aspx HYPERLINK "http://www.energifonster.nu/sv/rakna_ut_din_energibesparing.aspx" - If you would like to calculate how much you can save by replacing your current windows to triple glazing.
HYPERLINK "http://www.mgwc.org/"http://www.mgwc.org. - The Master Guild Of Window Cleaners
HYPERLINK "http://www.iwca.org/"http://www.iwca.org/ - International Window Cleaning Organization
HYPERLINK "http://www.nfmwgc.com/"http://www.nfmwgc.com/ HYPERLINK "http://www.nfmwgc.com/". - The federation of window cleaners
A Guide
Triple glazing is relatively uncommon, If you're unfamiliar with the concept of triple glazing, read our introduction to triple glazing.
The structure of triple glazing will give you a good idea of what is actual involved with the producing triple glazing, and why it costs more than double glazing.
Sound reduction is one of the factors that attracts buyers to triple glazing, so we've covered the subject of triple glazing for noise insulation in detail.
Before you buy triple glazing you'll want to know how something about measuring energy performance of triple glazing.
We have also put together some ideas to help you decide if triple glazing is worth it for your house?
Directory
The directory of
triple glazing suppliers.
Additional Information
Additional Additional.
