Can double glazed windows (IGU) keep scorching sun heat out of my room ?

tell me more what of IGU would work the best ? I like in an area that is unbearably hot in summers. I want light of the sun, but not the heat. What do I do ?

1 Answer

  • 8 years ago
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    If you want a full description try this website:

    Here is an extarct:

    The primary consideration for warm climates where glazed

    openings have little or no protection from the sun’s direct

    energy is the reduction of heat gain. The air gap in IGU’s

    slow down the rate of heat gain thus improving the thermal

    properties and energy efficiency when compared to a standard

    single glazed window. In these situations a tinted, reflective or

    a tinted Low-E coated glass such as Sunergy® is used on the

    outer layer or outboard lite of the IGU to control heat gain.

    Adding a low-E coating to surface position #2 acts like an

    additional barrier by further slowing the rate of the heating of

    the air gap. Having the coating on surface position #3 allows

    the air gap to be heated more quickly, because the low-E surface

    position #2 barrier is removed. This reduces the performance of

    the glazing in terms of heat gain to the interior of the building.

    The “E” in low-E refers to emissivity. Emissivity is a measure

    of a material’s ability to radiate energy. A material with low

    emissivity absorbs and radiates infrared energy poorly, which is

    the key factor in reducing heat transfer/gain/loss. The lower the

    emissivity of a coating, the better the glass insulates.

    As mentioned above, warm climate glazing requires a tinted

    or reflective glass to control solar heat gain. These traditional

    products (unless laminated with a hard coat low-E or applying a

    soft coat low-E) only allow low-E coat placement on surface #3.

    However, new generation products such as Sunergy® combine

    a tinted glass and low-E coating in one, thus allowing surface

    #2 placement and improved thermal properties. Consideration

    should always be given to toughening or heat strengthening of

    low-E panels in surface position #2 placement.

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