Glazing ratio, glass specification and shading geometry are usually settled on appearance and capital cost, then defended for the rest of the project. We test them against daylight, glare, cooling load and lighting energy together, and present the trade-off as a set of comparable options.
| Glazing ratio | More glass admits more daylight and more heat. The useful range is narrower than most schemes assume, and it is orientation-dependent. |
| Glass specification | Visible light transmittance against solar heat gain coefficient. A high-performance coating can hold daylight while cutting gain. |
| External shading | Geometry tuned to orientation and sun path: horizontal on south, vertical on east and west. The most effective single measure in this climate. |
| Interior control | Blinds, light shelves and daylight-linked dimming. Necessary, but no substitute for getting the façade right. |
A well-daylit floor plate reduces installed lighting hours, which reduces lighting energy and the cooling load that lighting creates. Handled badly, the same daylight arrives as glare and solar gain. Occupants close the blinds, the lights go on, and the cooling system carries both.
Spatial Daylight Autonomy. The share of floor area receiving 300 lux for at least half of occupied hours.
Annual Sunlight Exposure. The share of area receiving excessive direct sun, a proxy for glare risk.
Interior illuminance as a percentage of unobstructed exterior illuminance under an overcast sky.
Daylight Glare Probability. Occupant discomfort risk evaluated from specific view positions.