Reflective Coated Glass — Solar Control Coatings

What it is

Float glass carrying a metallic or metal-oxide coating that reflects part of the solar spectrum. It is the primary tool for meeting an SHGC target on a glazed Indian facade.

Specification at a glance

Property	Typical specification
Coating type	Pyrolytic (hard) or sputtered (soft)
Standard	EN 1096, class stated
Coating surface	Named by number, typically surface 2
Light transmission	Stated as a percentage
Solar factor	SHGC value stated for the build-up
Use	Soft coat only inside a sealed DGU

Hard coat against soft coat

	Pyrolytic (hard)	Sputtered (soft)
Durability	Can face outward, handled normally	Fragile; sealed cavity only
Thermal performance	Moderate	Substantially better
Toughening	Straightforward	Needs heat-treatable grade
Single glazing	Possible	Not suitable
Cost	Lower	Higher

What to state on the order

The coating name and manufacturer, the surface number, the glass thickness and build-up, the light transmission, the SHGC for the complete unit — not the monolithic pane — and whether the glass is heat-strengthened or toughened.

A coating performance figure quoted for a single pane does not describe the double-glazed unit that will be installed.

Where projects go wrong

• Surface number unstated, so the unit is assembled with the coating in the wrong position and the performance calculation no longer applies.
• Soft coat exposed on a single-glazed application. It degrades.
• SHGC quoted monolithic, then used in an ECBC compliance calculation.
• Reflectance chosen purely visually, without considering glare onto neighbouring buildings and roads.
• Mixed batches across one elevation. Coating colour varies subtly between production runs and shows on a continuous facade.

Standards referenced

Coated glass classification under EN 1096. Fenestration SHGC and U-value targets under ECBC 2017. Architectural safety glass to IS 2553 (Part 1).