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 ?
- BrambleLv 78 years agoFavorite Answer
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.