When the air at the coldest points in a house reaches its “dew point”, the water vapour in the air turns into condensation. These points are usually the single glazed windows and/or the aluminium frames. They allow the cold from inside to penetrate your home, as they do not act as “thermal breaks”.
Double glazing reduces condensation by forming a thermal barrier between your home interior and the cold outdoors.However, if you do not have a thermal break in the frame as well you will still get condensation. This is why timber frames work so well – they act as a natural insulator. The dew point is shown in the chart below. This chart is based on the temperatures at the centre of the glass, but the edges are always colder, and condensation usually begins there.
Thermal Properties - Double Glazing
Standard double glazing
The standard double glazing is the cheapest option in double glazing. It reduces the heat loss compared to single glazing by 55%.
Low E and argon glass
This glass option is the recommended glass option, as the U-value of the glass is approximately the U-value of the Eurotech WinDoors® timber frame. Windows with low E (low emissivity) film have a thin, transparent low E film suspended between two panes of glass in order to reflect heat energy back into the room. By adding argon gas, the glass is significantly better at reflecting heat back inside.
Thermal Properties - Triple Glazing
Triple glazing has three panes of glass (any glass combination can be used) with sealed spaces of ideally 12 mm inbetween. Some triple glazed windows can have a U-value as low as 0.9. You get more heat efficiency and therefore better heat retention compared to the double glazed versions.
Triple glazing greatly reduces noise and is often used near motorways or airports.
Injuries can happen if someone falls through a glass door or window, as ordinary glass breaks into big, irregular chunks. To prevent injuries, laminated or toughened glass can be used.
Toughened glass breaks into small granules less than 1 cm across which reduces the risk of major injuries, yet it retains all the qualities of ordinary glass.
Laminated glass does not break into large chunks but stays together and attached to the frame.
Common areas of impact risk where safety glass has to be installed include:
- Glazed doors
- Glazing adjacent to doors
- Low level glazing
- Bathroom areas
- Protective barriers
- Floor to ceiling glass walls
When considering windows there are generally three options available for maximum achievable sound attenuation (reduction):
- Laminated glass (normally with a interlayer of polyvinyl butyral or PVB)
- A wider air space between the panes of glass
- Different thickness panes of glass within the insulating glass unit (IGU)
- A combination of all three.
The sound transmission class (STC) measured in decibels (dB) is the standard method of rating the sound attenuation characteristics of glass products. The STC is an average of an object’s ability to attenuate sound across the entire sound frequency spectrum. STC does not deaden information, which may be what is needed if you want to block a specific type of unwanted noise that operates on a high or low frequency. The higher the STC rating means the higher the sound attenuation properties of the window. As with the thermal propertices, the acoustic performance of windows and doors is influenced not only by the glass but also by the frame and construction of the window.
U-value (thermal conductivity (W/(mK))
The thermal conductivity (U-value) describes how much warmth (watts/W) per metre (m) thickness per degree temperature difference (kelvin/K) flows though a component.
The lower the value, the less warmth is lost. In other words, good isolation is represented by a low thermal conductivity value.
- UFrame = 1.8 W/m2K (Meranti, Douglas Fir and Siberian Larch)
- UGlass = 1.6 W/m2K (24 mm Low E glass)
- UW = approximately 1.7 W/m2K
For privacy, pure style or to allow more light into internal rooms, decorative glass gives you a whole range of attractive options.
- Five levels of privacy are available, graded from 1 (least obscuration) to 5 (greatest obscuration).
- There are 12 original patterns in the main range and six in the replacement range.
- Toughened or laminated versions are available for safety and/or security.
Tinted glass can provide privacy, and reduce incoming heat and the damage caused by ultraviolet (UV) light (e.g the fading of fabrics).
Tinted glass is aesthetically pleasing and performance driven, with significantly reduced solar heat and UV light transmittance, as compared to uncoated clear glass products, yet it only slightly reduces the amount of light admitted into your home.
The inclusion of metal oxides creates tinted glass in a range of colors (e.g. bronze, grey, blue-green).
Tinted glass can give the outside of a building a more uniform, aesthetically pleasing appearance. Or, if you are more adventurous, you can use different tinted glass colours to create unique effects. White opaque glass is the most popular option for bathrooms or toilets.
Some customers decide for clear glass with Cosiflor blinds on the inside, so that they can retain the same overall look.