Solar Control Glass

Solar Control — Heat Rejection

The g-value (solar factor) indicates what proportion of solar energy passes through. A g-value of 0.33 means only 33% of solar heat enters — 67% is rejected. The selectivity index (light ÷ g-value) shows how well light and heat are balanced — higher is better.

Complete Product Range

Self-Cleaning + Solar Control Combos

Part O Compliance (2022)

Part O requires new residential buildings to limit overheating risk. Solar control glass is a primary compliance tool for south/west glazing. We recommend Suncool 66/33 (g=0.33) as a starting point, with Suncool 50/25 (g=0.25) for more demanding situations.

Solar Control vs Clear Float — At a Glance

*Typical values, centre-pane basis.

Summer Comfort on South & West Elevations

South and west-facing glazing takes the brunt of summer solar gain — low afternoon sun angles straight through vertical glass, and roof glazing sits under near-overhead sun for most of the day. Without solar control, large glazed areas on these elevations routinely push rooms into uncomfortable overheating by mid-afternoon, even with good ventilation. Cutting the g-value from a clear-float baseline of around 0.83 down to 0.25-0.40 removes the majority of that incoming heat before it reaches the room, while the glass still reads as clear or near-clear from both sides.

See how the coating rejects summer heat before it enters:

Solar Control

Summer Heat Rejected Before It Enters

The coating rejects most incoming solar radiation before it reaches the cavity — only a reduced amount of heat and light continues through to the room, which stays noticeably cooler.

g-value ≈ 0.25–0.40 typical High daylight retained

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Understanding Selectivity

Selectivity is simply light transmission divided by g-value — it tells you how much daylight you keep for every unit of heat you reject. A product with high light transmission and a low g-value has high selectivity: it lets the room stay bright without also letting it get hot. Two glasses can share the same g-value but feel very different to sit under — the one with the higher selectivity keeps more daylight for the same heat rejection.

Solar Control or Tinted Glass?

Choose solar control where heat rejection is the priority and a neutral, near-clear appearance matters — most south/west windows and roof glazing. Choose tinted glass where the look of the glass itself is the priority — a distinct bronze, grey or green tone — with some heat and glare reduction as a welcome side effect rather than the main goal. Both can be paired with Low-E in the same sealed unit for winter thermal performance alongside summer heat control.

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