Conventional Double Glazing

 Double glazing is comprised of two glass panes separated by a layer of air. In relation to single glazing, double glazing limits heat losses due to the insulating properties of the air in the chamber. Therefore:

it exhibits high natural light transmission.

its insulation against sound, heat and solar-energy can be further enhanced by replacing air with a noble gas such as argon.
This renders it thermal insulating, since argon acts as an insulator, resulting in the glazing – and, consequently, the frame – acquiring additional shielding against environmental conditions (solar energy, heat, sound).

The method used in assembling the double glazing will bring the desired results.

Double sealing, i.e., adding a first layer of insulating material before the main sealing is applied, is crucial.

In other words, double glazing in aluminium door & window frames :

  • reduces sounds from the exterior, making life within the home more peaceful.
    reduces heat losses through the home's doors & windows by about 10-12%, saving in electricity and heating oil.
    increases the security of door & window frames, hindering forced entry through the frame glass.
    improves the appearance of the frame, with a wide range of available designs and colours.




Safety Glazing



Triplex or laminated glass panes are created by joining 2 or more glass panes with an interlayer of transparent or coloured membrane.

This results in high strength against impact, as laminated glass, even when broken, is prevented from shattering by the internal supporting membrane.

The end result has the appearance of a single glass pane, and, when joined to another glass pane with intermediate air or noble gas insulation (e.g. Argon), it becomes double laminated glazing.

In the case of residences, laminated 3+3 or 4+4 glass panes are usually placed on the outside of the double glazing.


Securit is thermally toughened safety glass.

The toughening process provides significantly increased resistance to mechanical (bending and shock) and thermal (temperature fluctuation) stresses, with the same spectrophotometric properties as the base product of the same thickness.


A bulletproof glass pane is any laminated glass pane consisting of more than three glass panes and more than two membranes. The European Standard EN 1063 classifies bulletproof glass according to its resistance to various weapons and ammunition.

LOW-E Glass

low e glass

The new generation of Low Emissivity glass.

This type of glass allows light to pass through it, while at the same time providing thermal insulation.

This is the result of a special metal coating on the interior of one of the two glass panes (in double glazing), which exhibits high reflectivity to the infrared part of the radiation spectrum.

This coating consists of various microscopic metal-oxides which impede heat transfer from the outer side of the glass to its inner side and vice versa.

This means it does not allow heat transfer from the house's exterior to its interior and vice versa.

These coatings can be completely transparent of have various colour hues. The result is a glass pane which, in its final form, has the desired shade (tinted, bronze, pale blue, etc.).


When analysing the thermal losses as a result of the building's structural elements, we come to the following conclusions :

• 20% of heat loss is due to the roof
• 25% of heat loss is due to the walls
• 20% of heat loss is due to the flooring
• 35% of heat loss is due to the windows

Soft-coated Low-E glazing doesn't only reduce the amount of heat transferred from the building's exterior to its interior, it also filters solar radiation.

This allows them to greatly reduce the permeability of ultraviolet and infrared radiation, which would result in the wear of carpets, curtains, furniture etc., by up to 70%.

All of the above are determined by certain energy coefficients

There are three important coefficients when selecting the type of glass:

Α) Uvalue ή Κ - value W/m K: heat-transfer coefficient 

it expresses the rate of heat loss per square meter of glass pane between the inner and outer surface of the glazing, and is determined by a surface's ability to absorb or emit heat.
The lower the emissivity, the lower the heat-transfer coefficient K, and, therefore, the more energy-efficient the glazing.

Β) Solar Factor - g: solar factor,
it is one of the most important factors and expresses the percentage of overall solar energy-heat passing through the glass to the interior space.
Its values range from 0-1.
Due to the intense heat during Greek summers, it is very important to minimize its value (0), otherwise the glass functions as a heat passage that results in excessive interior heat, which overburdens the air conditioning units.

Γ) Light Transmission - LT: light transmission,

it expresses the percentage of visible light passing through the glass.
The higher the coefficient, the more light passes into the space.
A low light transmission coefficient increases the consumption in artificial lighting systems.
The ideal values of this coefficient range from 60% - 80%.

Therefore, for an optimal energy-efficient result, we should select glass panes with :

· Low Uvalue

· Low g

· High LT

In the summer, those panes:
1. reflect the sun's infrared light
2. act as a shield against indirect heat from the surrounding area –
facilitate cooling
3. reduce cooling costs (by up to 35%)
4. reduce artificial lighting costs

In winter, the panes:
1. act as a shield against heat trying to escape the interior -
provide more efficient thermal insulation
2. reduce heating costs (by up to 35%)

Low-E glazing allows us to manage solar light to our advantage, creating a comfortable environment with the lowest possible cost, both financially and in terms of energy-consumption.

For more information, please contact us.

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About Us

Founded on 1996 by Mr Theodoros Tsigkos, Center-Al developed to a big modern industrial facility which fabricates modern aluminium architectural systems.

Window and Door Replacement

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Chalkida Manufacturing Plant :
4th km Chalkida - Afrati Rd.
Tel. +30 22210 52772

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