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Insulated Glazing Unit or Insulating Glass Unit (commonly referred to as IGU) is described as two or more lites of glass spaced apart and hermetically sealed to form a single glazed unit with an air space between each lite. As the name suggests, the most important function of and IGU is to improve the thermal performance of glass when used in architectural applications.
The most commonly found IGUs are double glazed, i.e. made with two lites of glass and are therefore also referred to as "double glazing units" or "DGU" (especially in Europe) but IGUs with three lites or more, i.e. "triple glazing" are sometimes used for in very cold climates. Insulated glazing may be framed in a sash or frame or in a curtain wall. IGUs are also commonly used for replacement windows. A Georgian house in England with sash windows A sash window or hung sash window is made of one or more movable panels or sashes that form a frame to hold panes of glass which are often separated from other panes (or lights) by narrow muntin bars. ...
A window is an opening in an otherwise solid and opaque surface through which light and, sometimes, air can pass. ...
Glass curtain wall of the Bauhaus Dessau. ...
This article or section does not adequately cite its references or sources. ...
Insulating glass
Image File history File links Igu. ...
IGU made of glass is called insulated glass (which refers to heat insulation, not sound[1]). A more technically correct term, though, is insulating glass, since the glass itself has no insulative properties. It is actually the air space between the glass layers (lites) that provides the insulative qualities. Glass can be made transparent and flat, or into other shapes and colors as shown in this sphere from the Verrerie of Brehat in Brittany. ...
The air space between the lites may be filled with air or an inert gas like argon or krypton which would provide better insulating performance. Typically the spacer is filled with desiccant to prevent condensation and improve insulating performance. Less commonly, most of the air is removed, leaving a partial vacuum, which drastically reduces heat transfer through convection and conduction. This is called evacuated glazing. Layers of Atmosphere (NOAA) Air redirects here. ...
General Name, Symbol, Number argon, Ar, 18 Chemical series noble gases Group, Period, Block 18, 3, p Appearance colorless Atomic mass 39. ...
General Name, Symbol, Number krypton, Kr, 36 Chemical series noble gases Group, Period, Block 18, 4, p Appearance colorless Atomic mass 83. ...
A desiccant is a substance that adsorbs moisture from the air. ...
Water vapor condensing over a cup of hot tea Condensation is the change in matter of a substance to a denser phase, such as a gas (or vapor) to a liquid. ...
Convection in the most general terms refers to the internal movement of currents within fluids (i. ...
Heat conduction or Thermal conduction is the spontaneous transfer of thermal energy through matter, from a region of higher temperature to a region of lower temperature, and hence acts to even out temperature differences. ...
Often the insulating quality is used in reference to heat flow where the gap between glazed sheets is the insulating medium. This article is in the process of being merged into Heat, and may be outdated. ...
The air gap between the panes is generally between 12mm to 20mm thick. The thickness does not impact the insulating properties substantially i.e. a 12mm gap sealed unit is almost as good an insulator as 20mm sealed unit. In fact, a 20mm air gap sealed unit allows increased air circulation within, which impacts the insulation negatively. A 16mm air gap is considered the optimum thickness and is usually recommended by most users.
In some situations the insulation is in reference to noise mitigation. In these circumstances a large gap improves the noise insulation quality or Sound transmission class. Noise mitigation is a set of strategies to reduce unwanted environmental sound. ...
Sound Transmission Class (or STC) is an integer-number rating of how well a building partition isolates airborne sound. ...
Insulated glass may not be cut to size in the field like plate glass but must be manufactured to the proper size in a shop equipped with special equipment.
Glass coatings The heat and sound insulation of glazing may also be improved through the use of a film or coating applied to its surface. This film is typically made of polyester or metal, and may give a reflective appearance and one-way mirror effect to the window, and may improve both heat and sound insulation. This may be used on single-glazed windows as an alternative to insulated glazing, or on the outside layer of insulated glazing to further improve its effectiveness.[2] Such coatings may reduce fading of fabric and improve safety in the case of breakage.[3] A mirror is a surface with good specular reflection that is smooth enough to form an image. ...
"Secondary glazing" is sometimes used as a cheaper alternative. This consists of a layer of glazing placed retrofitted inside the window, to provide sound and heat insulation. Plastic sheet may be used for heat insulation, but may only last for one season.[4]
Low-emissivity coating Low-emissivity (Low-E) glass has a thin metal coating on the glass within its airspace that reflects thermal radiation back into the interior, and allows solar radiation into the room. Thus, the coating helps to reduce heatloss but allows the room to be warmed by any sunshine.The low-e coating is on the inside pane of glass, if solar control is required then the outside pane of glass would have either a film or a body tint to reflect solar radiation. The principle of operation is similar to the greenhouse effect where short wavelength radiation is transmitted through the pane, but longer wavelength radiation is reflected. Low-emittance (Low-E) coatings are microscopically thin, virtually invisible, metal or metallic oxide layers deposited on a window or skylight glazing surface primarily to reduce the U-factor by suppressing radiative heat flow. ...
Thermal radiation is electromagnetic radiation emitted from the surface of an object which is due to the objects temperature. ...
Solar irradiance spectrum at top of atmosphere. ...
A schematic representation of the exchanges of energy between outer space, the Earths atmosphere, and the Earth surface. ...
See also Glass curtain wall of the Bauhaus Dessau. ...
Glass can be made transparent and flat, or into other shapes and colors as shown in this sphere from the Verrerie of Brehat in Brittany. ...
When discussing the properties of windows and shading devices, the G-value is one of the properties you will hear mentioned. ...
External links - Double Glazing Insulating Glass Blog - Blog concerned with research, development and manufacture of decorative applications in double glazing insulating glass units with aerogel components.
- Energy Efficient Windows and damage to trees / landscaping
- Double Glazing
- Project Guides - brief description and how-to for secondary glazing.
- GlassMagazine.net - Articles - insulating glass may not help with sound.
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