The Tropical Façade Problem

A glass façade in Accra faces a problem a glass façade in a cool climate does not: the sun is strong, high and present all year. Left unmanaged, that solar gain turns a glazed building into a greenhouse and pushes the air-conditioning system — and the electricity bill — hard, every day. The answer is not more cooling; it is a façade engineered to let light in while keeping heat out, so the building works with the climate rather than against it.

Facade Ghana engineers solar-optimised façades for Ghana, since 1982. This guide explains the levers that control solar gain and how they fit together.

SHGC — The Number That Matters Most

The single most important property of a tropical façade glass is its Solar Heat Gain Coefficient (SHGC): the fraction of the sun’s heat energy striking the glass that ends up inside the building. A lower SHGC means less solar heat gets through, which means a lighter cooling load.

In a cool climate you might want a high SHGC to gain free winter heat. In Accra the opposite is true — you want a low SHGC to keep solar heat out, while still letting in enough daylight to avoid relying on artificial light all day. Balancing a low SHGC against good visible-light transmission is the core of tropical façade glass selection. (We specify the SHGC and light-transmission targets to the building and orientation rather than quoting a single number for every façade.)

The Glass Levers

Low-E (Low-Emissivity) Coating

A microscopically thin metallic coating on the glass that reflects a large part of the sun’s infrared (heat) energy while letting visible light through. In the tropics, a solar-control low-E coating is the workhorse for cutting solar gain without making the glass dark.

Solar-Control Tints and Coatings

Body-tinted or surface-coated glass that reduces the total solar energy entering. Used with — or instead of — low-E to bring the SHGC down further on heavily exposed elevations.

Double Glazing (Insulated Glass Units)

Two panes with a sealed gap reduce conductive heat transfer and, combined with a low-E coating on the right surface, give a far better-performing unit than single glazing. The make-up — single, double, low-E, laminated, solar-control — is part of how the façade is priced.

Beyond the Glass — External Shading

Glass alone is not the whole answer. The most effective way to cut solar gain is to stop the sun reaching the glass at all, with external shading designed to the building’s orientation and the sun’s path.

Brise-soleil and fins — horizontal or vertical shading elements that block high or low-angle sun depending on the elevation.
Overhangs and recesses — shading the glass from the high midday sun while keeping lower morning and evening light.
Orientation-aware design — east and west elevations take low-angle morning and evening sun that overhangs cannot block, so they often need more glass-level control or vertical fins; north and south elevations respond well to horizontal shading.

External shading works with the solar-control glass, not instead of it — together they cut the cooling load far more than either alone. See Solar-Optimised Façade.

Why This Cuts the Cooling Load

Every watt of solar heat that gets through the façade is a watt the air-conditioning has to remove — all day, every day, for the life of the building. A façade with a low SHGC, the right low-E glass and external shading lets in daylight while keeping that solar heat out, so the cooling plant runs lighter and the electricity bill is lower year-round. A lower-priced façade that under-specifies the glass wins on the first invoice and loses on every cooling bill after it. The solar-control envelope is engineered once and pays back continuously.

It is the same envelope that must still perform on air, water and wind — so solar-control glass is specified inside a properly engineered and tested façade system, not bolted on as an afterthought.

Frequently Asked Questions

What is SHGC and why does it matter in Ghana? SHGC (Solar Heat Gain Coefficient) is the fraction of the sun’s heat striking the glass that ends up inside the building. In Accra’s strong year-round sun you want a low SHGC, so less solar heat gets in and the air-conditioning works less. A low SHGC balanced against good daylight transmission is the core of choosing tropical façade glass.

Does solar-control glass make a building dark inside? Not if it is specified well. A solar-control low-E coating is designed to reflect infrared heat while letting visible light through, so the glass can have a low SHGC and still transmit good daylight. We specify the glass to balance heat rejection against daylight for the building and its orientation, rather than just making the glass dark.

Is external shading worth the cost over solar-control glass alone? Often yes, especially on heavily exposed east and west elevations. Stopping the sun before it reaches the glass is more effective than rejecting it at the glass alone, and the two work together to cut the cooling load further. The right balance depends on orientation, glass specification and budget — which is what the survey and design stage resolve.

Talk to the Façade Team

A façade that fights Accra’s sun with more air-conditioning is a façade specified wrong. Facade Ghana engineers the envelope — solar-control glass, low-E coatings and external shading — to cut the cooling load for the life of the building. Call +233 27 000 0844 to book your survey.