Low-E Glass , Energy Efficient glass
Low-e glass stands for low emissivity glass. This glass varies from normal clear glass in that one side of the glass has a special metal coating, technically known as a low emissivity, or Low E. coating. Low-E glass is a type of insulating glass, which increases the energy efficiency of windows by reducing the transfer of heat or cold through glass. That means in the winter your house stays warmer, and in the summer it stays cooler.
There are two types of Low-E (low emissivity) glass available: hard coat and soft Coat
Hard Coat Low E Glass (pyrolytic glass)
Hard Coat Low E Glass (pyrolytic glass)
Sunergy Glass
We have several low-e glass types including our hard coated low-e glass “Sunergy” glass product.
Sunergy is the answer to the most advanced architectural requirements. Its processing qualities make it a favorite choice for award-winning contemporary architecture and complex construction.
Sunergy combines neutrality with low reflection, which allows objects to be seen in their true colors. Sunergy pyrolytic coated glass combines advanced energy efficiencies solar control and thermal insulation, making it the ideal glass for all seasons.
Sunergy is manufactured by pouring a thin layer of metallic oxide onto a sheet of glass while the glass is still on the float line. The metallic oxide layer becomes “welded” to the glass surface. This process makes it very difficult or “hard” to scratch or remove the coating – which is why it is referred to as “hard coat”. Often this glass has a bluish tint to it.
Sunergy is ideally suited to be combined with other solar control glass such as planibel or comfort E2 glass for superior thermal efficiencies
Planibel G and Comfort E2 Hard Coated Low-e Glass
The Low-E coating is applied on a sheet of clear float glass by a pyrolytic process called CVD (Chemical Vapour Deposition) process.
In winter, the aim of the coating is to reflect the heat back to the building to prevent heat loss and keep the climate indoors at an even temperature.
In summer, the coating will reduce the amount of re-radiated heat entering the building thereby keeping indoors cooler. Total heat gain is reduced.
Planibel G fasT
PLANIBEL G FasT is a special version of PLANIBEL G that has been specially engineered to be toughened like ordinary float glass.
Planibel G Fast can be Toughened and annealed² Planibel G and G fasT can be combined on the same façade depending on the level of safety required. In addition to having the same neutral appearance, the two products have the same properties, including double glazing units with increased thermal insulation, high light transmission and low reflection. Planibel G fasT can also be assembled into laminated glass for increased safety, or even combined with solar control glass. Technical information on Planibel G and Planibel G fasT Composition Planibel G fasT - 4 - 15 Light transmission (%) - 74 % Light reflection (%) - 18 % Solar factor (%) 72 % U-value, 100% Argon W/m².K - 1,5 ¹ Internal and external tests ²
Advantages
- The advantage is that the coating is relatively durable, which allows for ease of handling and tempering.
- Can be toughened after the coating application.
- Can be used in single glazing applications.
- Utilizes passive solar heat gain.
- Planibel G and Planibel G fast can be combined with each other or other solar control glasses for extreme performance.
- Improved scratch resistance of the coating
Advantages
- The advantage is that the coating is relatively durable, which allows for ease of handling and tempering.
- Can be toughened after the coating application.
- Can be used in single glazing applications.
- Utilizes passive solar heat gain.
Disadvantages
- Higher U-values compared to soft coat Low-E products
- Slightly higher haze levels
- Higher solar heat gain coefficient compared to soft coat Low-E products.
- Hard coat glass also has the possibility of a slight haze, which can be visible under certain angles.
Soft Coat Low E Glass (Sputtered Low-e glass vacuum deposition or soft coat)
Soft coat Low E, or sputter coating, is applied in multiple layers of optically transparent silver sandwiched between layers of metal oxide in a vacuum chamber. This process provides the highest level of performance and a nearly invisible coating.
Advantages
- High visible light transmission
- Ultra-low emissivities giving optimum winter U-values
- Up to 70% less UV transmission compared with standard clear glazing
- Optical clarity - minimal color haze
Disadvantages
- Soft coat Low E must be used in a double glazed unit; the soft coating is sensitive to handling.
- Most soft coat Low-E products require tempering the glass prior to the coating application.
- Edge deletion of the coating is required to insure a proper seal in an insulated unit
- There can be slight color variations of coating.
- Generally speaking, a more expensive alternative than Hard Coat Low e glass.
Low-e glass, how does it work?
The radiation coming from your heating system and your furniture and furnishings is long wave radiation. This type of radiation should be contained in your room as best as possible, while the radiation from the sun should be shielded and reflected back outside.
Winter/Cooler Months
The sun's energy is "SHORT WAVE RADIATION" which passes through the window and is absorbed by carpet, furniture, etc. The energy is then transformed into long wave radiation. The long wave radiation wants to flow from warm to cool. Naturally, it will try to escape from the glass. At night the heat produced from radiators, wood stoves, etc., will also want to escape out through the glazing. The Low-E coating prevents this when the radiant room-side heat is reflected back into the building. This results in a lower winter U-value. For winter comfort, the higher the indoor glass temperature, the better the product is for comfort.
Summer/Warmer Months
The Low-E coating manages the sun's heat in the summer by reducing the amount of heat transferred through the window in the summer. The Low-E coating filters the sun's short-wave radiation, which cuts down on the amount of solar heat gain into your building. For summer comfort, the lower the indoor glass temperature, the better the product is for comfort.
