Hard Coat Low E:

Hard coat Low E, or pyrolytic coating, is a coating applied at high temperatures and is sprayed onto the glass surface during the float glass process.

Advantages
• The advantage is that the coating is relatively durable, which allows for ease of handling and tempering.
• Can be tempered after coating application.
• Can be used in single glazing applications.
• Utilizes passive solar heat gain.

Disadvantages
• Higher U-values compared to soft coat Low-E products
• Slightly higher haze levels
• Higher solar heat gain coefficient compared to soft coat Low-E products.
• Hard coat glass also has the possibility of a slight haze, which can be visible under certain angles.

Soft Coat Low E:

Soft coat Low E, or sputter coating, is applied in multiple layers of optically transparent silver sandwiched between layers of metal oxide in a vacuum chamber. This process provides the highest level of performance and a nearly invisible coating.

Advantages
• High visible light transmission
• Ultra-low emissivities giving optimum winter U-values
• Up to 70% less UV transmission compared with standard clear glazing
• Optical clarity - minimal color haze

Disadvantages
• Soft coat Low E must be used in a double glazed unit; the soft coating is sensitive to handling.
• Most soft coat Low-E products require tempering the glass prior to the coating application.
• Edge deletion of the coating is required to insure a proper seal in an insulated unit
• There can be slight color variations of coating.
• Generally speaking, a more expensive alternative than Hard Coat Low e glass.