Universe Corporation

Fact: Daylighting does not have to increase construction costs if it’s done using an integrated design approach. An integrated approach considers the effect of lighting on air conditioning.

The electric lights in modern buildings produce a lot of heat, while properly directed natural lighting generates almost no heat at all.

The decrease in internally generated heat allows designers to downsize the air conditioning system. The resulting cost reduction helps pay for daylighting improvements.

Fact: It need not be. Daylighting designs that work in most commercial and educational buildings.

The result is reproducible energy savings and performance, minimal investment of design time and no risk.

Fact: The light-to-heat ratio for daylighting is far better than even the most efficient electric lights.

Properly designed daylighting screens out 99 percent of the sun’s heat while providing 50 foot-candles of light, which is more than enough for most tasks.

Fact: Glare happens when too much light enters a building. And this happens all the time in conventionally lit buildings (notice the drawn blinds in the windows of most office buildings).

A properly daylit building uses carefully placed windows, shading devices, low-transmittance glass, translucent sandwich panels and tubular daylighting devices—techniques that block direct sunlight and greatly reduce glare.

Fact: It’s better to reduce the need for electric lighting and cooling in the first place. Cool daylighting does both.

Natural light reduces the amount of installed electric lighting (within the limits of what’s needed for nighttime use).
Less electric lighting means less heat gain, which means less heat to remove with air conditioning, using less energy.

What lighting and cooling is left can then be done by the most efficient equipment available. Being efficient is always a good idea, but needing less energy is even better.

Fact: Clear glass windows let in too much light, far more than what’s needed for effective lighting.

The sun provides 7,000 to 10,000 foot-candles of light, while indoor office spaces need only about 50 foot-candles.

Too much light causes glare and the "cave effect", where the back of the room appears dark compared to other surfaces. This encourages people to close the blinds and turn on overhead lights to cut down the contrast in the room.

Well-designed daylighting lets in natural light that balances overhead electric lighting while curtailing glare.

Fact: Properly designed skylighting is a good technique in certain situations, and can be an architectural feature.  Translucent sandwich skyroof panels and tubular daylighting devices deliver top daylight effectively, such as enclosed hallways or very deep spaces.

Translucent clerestory panel systems—near the top of the wall—bring light in high in the room, producing a natural diffuse glow on the ceiling that mimics our experience of the sky.

Skylights aren’t usually needed to achieve good results until you get beyond 25 feet of the perimeter windows.

Fact: Even a completely overcast sky provides 5,000 to 6,000 foot-candles of illumination—a hundred times more light than needed for daylighting.

In some ways, overcast skies typical of northern climates provide a better lighting source because the light is more diffuse and even.

Fact: Specific daylighting techniques vary, depending on location, number of building stories, building orientation and computer use in the building.

Daylighting techniques can be adapted to meet the needs of almost any building, whether it’s a warehouse, school, office, or government building.

Fact: All-glass buildings don’t provide good daylighting because they get too hot and have massive problems with glare.

Windows constitute about 25–40 percent of the wall area of effectively designed daylit buildings. On average, window area in daylit buildings isn’t all that different than windowed area in non-daylit buildings.

Good daylighting technique depends on the proper placement of windows and performance characteristics such as visible light transmittance and solar heat gain coefficient—not having large amounts of glass; and also rely on other proven, effective daylighting systems such as translucent sandwich panel systems and tubular daylighting devices.