'K' Glass against Low 'E' Glass

Can someone please let me now the +'s and -'s between 'K'Glass and Low 'E' Glass, I have been told that Low 'E' is the best, is this true. If so is there one one type of low 'E' or is there diffarent types'???

Guest User
Thu, 08/02/2007 - 13:32

Most of the glass fabricators (around the world) are fortunately capable to properly handle low e soft coatings.

K glass presents a major disadvantage: its emissivity is not very low compared with vacuum deposition low e.

Therefore insulating glass made with K Glass presents U values which are not low enough to reach needs expressed by many customers.

Current vacuum low e, made by vacuum deposition, with double silver layer, being able to be tempered are the best products customers can expect to make IG units they need to assure thermal comfort they request.

Guest User
Tue, 06/02/2007 - 20:34

K-Glass is a Pilkington hard 'pyrolytic' coated glass where the coating was applied at the float line process (when the glass was hot). It is a very robust coating and can be tempered with ease but its emissivity is in the region of 0.3. (Float glass is around 0.98)

Soft coated Low-E glass has the coating spluttered on after the float process. The coating on the glass is not very robust, it is easily damaged and will absorb moisture if left unprotected and will break down (it is also easily damaged by moist finger and palm prints). In other words it must be handled with care and assembled into a double glazed unit quite quickly after a pack has been opened(see the different manufacturers specification sheets for their maximum recommended times). The upside of soft coated glass is that the emisivity is down in the range of 0.03 or below, making the finished glass unit a far better insulator. Some types of soft-coat can be tempered (they have a sacrificial layer which is allowed to burn off) and some types can’t be tempered, but even those ‘temperable’ types are relatively difficult to temper compared to clear glass, plus of course, the coating must be removed where the sealant is going to adhere to the glass (edge deletion) in a double glazed unit.
Hope this helps put it in perspective.
Jonathan Barr

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