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Thermal insulation

Thermal insulation is accomplished in two ways:

  • Simple double glazing (2 glass panes are united with an alouminium spacer, and filled with gas for better performance)
  • High performance double glazing (when one of the glass panes is coated: low-e glass ή high-performance glass)

In addition U-value (or k-value) can be improved with the use of:

  • filling with gas (argon, krypton)
  • wider alouminium spacer

Following are the U-value pricesof the main combinations of glass types, so that one can understand the way of improving thermal insulation(U-value):

Glass Type U-value or K-value
4 mm Clear 5.8
Laminated 33.1 Clear 5.7
Laminated 55.1 Clear 5.6
4 mm Clear - 9 - 4 mm Clear 3.3
4 mm Clear-12-4 mm Clear 2.9
4 mm Clear-15-4 mm Clear 2.7
4 mm Clear-9 argon-4 mm Clear 2.8
4 mm Clear-12 argon-4 mm Clear 2.7
4 mm Clear-12 argon-4 mm Clear 2.6
4 mm Clear-9-4 mm Low-e 2.0
4 mm Clear-12-4 mm Low-e 1.7
4 mm Clear-15-4 mm Low-e 1.5
4 mm Clear-9 argon-4 mm Low-e 1.6
4 mm Clear-12 argon-4 mm Low-e 1.3
4 mm Clear-12 argon-4 mm Low-e 1.2



This type of glass refers to group of products which have one side coated: a thin microscopic layer of metallic oxides has been placed on one side of the glass, intending to reduce the solar energy transmission. This gives the glass better insulating performance without differentianing it from the usual glass type -in terms of light reflection and transmission- making it suitable for residential use.

Low-e glazing improves significantly cofort levels, by bringing the glazing's surface temperature close to the room temperature. In this way low-e glazing increases the comfort levels and reduces the phenomenon of Cold Zone around the glazing area noticed in winter time.

In single glazing, Low-e glass can be idealy applied in deep freezing conditions when thermally treated. In double glazing units the use of low-e can offer high prices of thermal insulation. Compared to single glazing, double glazing of ordinary glass panes can reduce thermal loss at about 40%, improving massively thermal insulation of buildings (residential or industrial).

Available products:

  • Pilkington K Glass TM

Pilkington K Glass TM

High Performance solution for improved thermal insulation for residential and industrial buildings in cold climates. This is a reflective glass with hard coating of neutral color, in the thickness of 4 mm. It can be thermally treated for securit or laminating.

The coated side comes always in position 3 in double glazing. The coating reflects the heat back to the inside of the building, while at the same time it allows the solar energy penetrate the glazing system (increasing Heat Gain).

How it works:

Low emmissivity coating is a very low driver to heat, preventing it to leak outside the building. It practically insulates the interior of a building protecting it from heat loss. This results in significant reduction of energy and money.



High performance glass that combines in one product solar control properties together with low-e coating, making it a special product for the warm climate zone where there is a growing demand for strong thermal insulation both in winter and in summer time.

Reduction in energy cost comes in two ways:

During summer time SUNERGY coating absorbs almost half of solar energy, preventing it to enter inside the building, and reflects it back to the environment. During winter time it prevents heat loss from the interior to the environmet by absorbing it and reflecting it back inside the building. 


  • Great economy in heating and cooling cost : Reduces up to a 30% thermal loss from glazing
  • Ideal for warm climates : High performance protection from solar energy trasmission
  • Excellent control of visual light, in combination with LOW-E properties (thermal insulation) in one product
  • Hard coated glass with limitless life-span and high resisatnce to weather conditions, scratching, air pollution etc.
  • High levels of light transmission
  • Low light reflection
  • Especially neutral (does not change colors)
  • Aesthetically advanced
Light / Thermal Performance Sunergy 6 mm
- 12 Argon - 6mm
6 mm - 12 - 6 mm
U value (or K value W/m2K) 1,8 2,8
Heat Gain Coefficient 52 % 72 %
Shading Coefficient 53 % 83 %
Light Transmission 61 % 79 %
Light Reflection 12 % 14 %
UV Transmission (Ultra Violet) 27 % 38 %
Solar Factor 41 % 72 %
S. Varnakiotis Glass S.A  Glasses - Aluminium Systems Schüco

Address: 11 Greka str., 26500 Paralia Patron, Greece
Tel: +30 2610 522102, +30 2610 522124
E-mail: info@varnakiotis.com

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