You may need to choose the glass product?according to?the local building regulations. Normally in the north region of China, it is cold and severe cold area, then the lower U- Value?becomes the most?important?factor for you when choose the glass.?For example, the SGG PLANITHERM is most popular in north regions, with higher Light transmittance, and lowest U-Value=1.16 w/m2. k?(with 6+16Ar+6).?

Or in severe cold area, the triple double glazing unit with low-e coating is also one of the best solution for energy saving.