Sealed units

Manufacturers claim that over 25% of the heat in your house escapes through your windows! Choose from a range of window energy rating systems, given a scale from A to G. A rated windows are the most energy efficient.  All sealed units are filled with argon gas. The spacer bar colour can be chosen by the customer for example silver, bronze, black and gold.  There can be some outside condensation, this proves the units are working (keeping the cold out and warm in), click here for more information.



Saint-Gobain say:

"Haze can occur on most coated glass, both hard and soft coated.  However, the effect will be more noticeable on some types of coated glass than on others.  Haze gives the appearance of a fine, uniform, layer of dust deposited on the surface of the glass.  The effect is more noticeable when the glass is viewed at an angle or under strong light.  In situations where the glass is in partial shadow, the shaded area will be free of the effect giving a clean appearance in the shadow and a dusty appearance in the lit area.  This contrast can be very noticeable.  Manufacturers aim to limit this effect as far as is possible, but it cannot be total negated."


Pilkington say:

"Haze is an optical phenomenon which makes the glass look like it is covered in a very fine, uniform, layer of dust when viewed from an oblique angle or viewed under strong light incident on the glass at an oblique angle.  Pilkington K Glass can, under certain lighting conditions, display this phenomenon to a limited extent.  The reason for this is that the  Pilkington K Glass coating is not as smooth as the glass surface.  While this is not obvious to the eye when examining the glass, some people who regularly handle Pilkington K Glass can tell which side the coating is on by the feel of it.  The optical effect of the slightly rougher surface is to scatter a small proportion of light incident on it (in exactly the same way as a thin layer of dust would, which is why it looks similar).  With Pilkington K Glass, the amount of scattered light is generally less than half of 1% of the light coming through the window, so under most viewing conditions it is not obvious.  However, when incident sunlight is at an oblique angle and the view through the glass is of a shaded area, then the scattered light can become more visible, giving rise to the appearance of haze.  Most coated glasses are susceptible to a phenomenon of haze, to a greater or lesser extent and the amount of haze on Pilkington K Glass is limited as far as practicable."


Toughened Glass

Toughened glass should be used at low level. For example in doors (at sides, below or above). Toughened glass has a small stamp in the corner of the glass.


Self-cleaning glass

Self-cleaning glass is available as Pilkington have introduced the Activ range. It is excellent for conservatories. Rain water washes away the dirt which will have been loosened by the coating breaking down the dirt deposits.  To find out more, click here to visit the Pilkington self cleaning glass page.




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Glass and Glazing Federation Quality of Vision leaflet
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Textured Glass

Here are a few of the textured (obscure) glass choices available.