Daylighting: Here's why natural light is the greatest tool of modern architecture

Daylighting, or the use of natural light inside a building, is one of the simplest and best ways to reduce overheads and increase profits.
Christopher McFadden
Interior of blank room with rough floor.
Interior of blank room with rough floor.

zhudifeng/iStock 

  • One of the best ways to reduce a building's energy consumption is to maximize the amount of natural daylight allowed inside the building.
  • By doing this, an internal space like an office or shop can be transformed.
  • But, like anything in life, daylight use strategies are very much a trade-off between its benefits and downsides.

The use of natural light is one of the most important aspects of architecture because it affects people's well-being, saves energy, and makes environments more comfortable. Of course, natural light was a major source of illumination for many until modern times.

However, after the invention of electrical lighting, uptake was rapid because of the benefits it offered, and it was installed into most large structures in a matter of years. Buildings today are designed to let in more natural light in part because of a desire to save energy, as well as a greater understanding of the health benefits of light.

What is a daylight system?

Daylighting is when direct sunlight and diffused skylight are let into a building in a controlled way. This cuts down on the need for electric lighting, which helps reduce the building's use of energy. It is the practice of designing the placement of windows, skylights, and reflective surfaces to allow sunlight to provide internal lighting.

Daylighting: Here's why natural light is the greatest tool of modern architecture
The use of daylight can save significant amounts of energy on lighting.

In addition to lowering energy costs significantly (sometimes as much as 75 percent), effective daylighting helps create a visually engaging and productive environment for building occupants by connecting them directly to the dynamic and constantly changing patterns of light outside.

Along with openings like skylights and windows, daylighting systems often also incorporate a lighting management system that responds to daylight. For example, automatically raising or lowering the artificial light used in a building in response to the changing levels of natural light. This technology has the capacity to generate more savings and use less electricity.

Also, the placement of windows and doors on the elevations of a building (fenestration) needs to be planned so that direct sunlight doesn't hit work surfaces or people's eyes. Tools that provide dynamic shadings, such as motorized exterior louvers to automated roller shades and blinds, can help with glare and are often used for this purpose.

Daylighting: Here's why natural light is the greatest tool of modern architecture
Daylighting can transform an office space.

To use daylighting effectively on a project, architects and designers need to do more than just figure out what parts need to be gathered and put in place. Daylighting requires an integrated design approach because it might involve decisions about the building's shape, location, climate, building components (like windows and skylights), lighting controls, and lighting design criteria.

Depending on where you are in the world, daylighting may be a required element of the design of a new building, and architects must refer to their local building regulations for more detailed guidance.

What is meant by daylighting?

The science of daylighting design involves not only figuring out how to give an occupied room enough light but also knowing how to do so while minimizing the negative side effects. It entails carefully managing heat gain and loss, glare management, and changes in daylight availability, in addition to the placement of windows or skylights in a space.

In a successful daylighting design, the use of shade equipment to reduce glare and prevent too much contrast in the workspace would be carefully thought out. Also, the size and spacing of the windows, the type of glass used, how reflective the surfaces inside are, and where any internal barriers are should be thought about.

Daylighting: Here's why natural light is the greatest tool of modern architecture
Good office design is important for maximizing daylight use.

Systems, technologies, and architecture all combine in the make-up of a daylighting system. Even though not all daylighting systems or designs must have all of these elements, most do have one or more of the following:

  • Daylight-optimized building footprint
  • Climate-responsive window-to-wall area ratio
  • High-performance glazing
  • Daylighting-optimized fenestration design
  • Skylights (passive or active)
  • Tubular daylight devices
  • Daylight redirection devices
  • Solar shading devices
  • Daylight-responsive electric lighting controls
  • Designing the space to optimize daylighting (such as furniture design, space planning, and room surface finishes)

Because daylighting features are usually built into the original design of a building, it is important to note that sometimes it is not possible to integrate them during later refurbishments or retrofits.

However, for new builds, the building footprint should be made as daylight-friendly as possible. If the project allows, it is always advisable to design the building with a footprint that makes the most of south and north exposures while minimizing east and west exposures.

Daylighting: Here's why natural light is the greatest tool of modern architecture
Daylighting can significantly reduce a building's reliance on artificial lighting.

However, there are limits. For example, it has been demonstrated that daylighting is feasible with a floor depth of no more than 60 feet from south to north. The ideal orientation is often a maximum facade facing due south too. For the best sun access and simplicity of control, the deviation from straight south shouldn't be more than 15° in either direction.

What are the types of daylighting systems?

Once the building is in the right location, the next major design consideration is the windows/fenestrations themselves.

The window area needs to find a good balance between letting in light and dealing with thermal issues like heat loss in the winter and heat gain in the summer. Even high-performance glazings don't have insulation ratings that come close to those of walls for obvious reasons.

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Daylighting: Here's why natural light is the greatest tool of modern architecture
Window design is critical to daylighting systems.

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This is very much something of a trade-off between the benefits of added daylight (and cost savings) and the additional cost of heating/cooling that may be a consequence.

Compared to a regular window pane, a high-performance glazing system usually lets in more light and less heat. This makes it possible to use natural light without making the building harder to cool in the summer.

In addition to the factors above that have to do with windows, a daylighting-optimized fenestration design will also improve the performance of the heating and cooling systems.

In a building that lets in daylight, the window is important for two reasons:

  • It lets in daylight (which is the entire point)
  • It gives the people inside a view (obviously a nice benefit, too, and can enhance psychological well-being).

In general, the higher the window head height, the farther into the room daylight can reach. Best practices for daylighting fenestration include having a daylighting window and a view window.

Daylighting: Here's why natural light is the greatest tool of modern architecture
Taller windows are best for maximizing daylight penetration.

Another strategy is to install skylights.

In daylighting plans, skylights are often used to provide top lighting or let light in from above. The majority of skylights are passive because they feature a clear or diffusing medium (often acrylic) that merely enables light to pass through an opening in the roof, despite the fact that skylights can be either passive or active.

To improve insulation, they frequently include two layers of material too. Active skylights, on the other hand, have a mirror system inside that may follow the sun and direct light into the skylight well. This is meant to make the skylight work better and provide more light. Some of these systems also make an effort to balance cooling loads with daylighting during the summer months.

Daylighting: Here's why natural light is the greatest tool of modern architecture
Skylights are another handy way to maximize internal daylight levels.

Another type of top lighting device is daylight or sunlight tubes. These devices use a highly reflective material inside a tube to direct light from a lens on the roof to a lens on the ceiling plane. Even though tubular daylight sources are usually much smaller than regular skylights, they still let in enough light to reduce the need for electric lighting.

Another method is to use something called daylight redirection devices. These move or "bounce" direct beams of sunlight, usually onto the ceiling of a room.

Daylight redirection devices move direct beams of sunlight, usually onto the ceiling of a room. These fixtures have two purposes: to reduce glare by deflecting direct sunlight away from eye level; and to allow daylight to enter spaces where it might otherwise be difficult to place a window or skylight. Devices that change the path of sunlight usually have one of two shapes: a wide horizontal element or a system of slats. Light shelves are commonly used to describe horizontal daylight redirection systems.

What are the limitations of daylighting systems?

Daylighting systems come with some very important benefits, but they are not completely foolproof. Because of the nature of many of the devices and strategies, new issues tend to be introduced too.

Daylighting: Here's why natural light is the greatest tool of modern architecture
Daylighting is not perfect, it does have downsides.

One of the most important, as was already stated, is that the window placement and design need to be planned well so that solar gains and unwanted glare caused by a daylighting design can be dealt with. To reach this goal, people often use solar shading devices, especially on view windows, to cut down on the amount of direct sunlight that comes into the room.

Called overhangs, this is a very simple and very common architectural "fix." These can either be completely fixed or passive (like a fixed awning) or more active, like motorized and automated brise soleil systems.

Again, considerations for the installation of such systems are yet another trade-off as any active systems will consume electricity to operate. So long as the benefits outweigh the gains, then these are excellent options to overcome solar gain and glare.

Another issue is that any daylighting system must have controls for electric lighting that respond to changes in daylight. A daylighting design that saves energy won't work unless the electric lights are dimmed or turned off when natural light is high enough.

Daylighting: Here's why natural light is the greatest tool of modern architecture
Artificial lights actually produce heat too!

In fact, a daylighting-enhanced building could use more energy than a similar building without daylighting features if daylighting features like windows and skylights aren't paired with daylighting features like dimming controls that change based on the amount of daylight. The continuous dimming or stepped-ballasts in the light fixtures and one or more photocells that detect the amount of light and dim or switch off the electric lighting in response are some of the main components of daylight-responsive lighting controls.

Related to this, another factor that is sometimes not necessarily considered is the impact on the heating and cooling systems of the interior of a building. Artificial lighting, depending on the type of bulb used, tends to generate excess heat that is released into the space.

This can have an appreciable impact on the cost of heating/cooling a space during summer or winter. Older incandescent bulbs, for example, dump about 90- to 98 percent of their consumed energy as heat!

Daylighting: Here's why natural light is the greatest tool of modern architecture
Daylighting systems also need smart lighting controls for best results.

By limiting the need for artificial lighting to light a space, there will be an associated impact on the costs of heating a space during colder weather spells.

The reduced "waste" heat from lighting can actually be quite significant, and this will need to be "replaced" by increasing heating input into a space.

Another consideration, as we've previously touched upon, is the need for serious consideration of the interior design of the space. This is a crucial component and is frequently ignored or overlooked in some daylighting designs.

When designing a space that makes the most of natural light, the layout of the furniture, how the surfaces are treated, and how the room is laid out should all be taken into account.

To help "bounce" and distribute the redirected daylight more effectively, for instance, office cubicle partition heights may need to be restricted, especially those that run parallel to the south facade; enclosed offices will need to be kept to a minimum, and walls and ceilings may need to be as highly reflective as possible.

Sunlight management is made easier with smaller solar shading devices by placing work surfaces away from the south facade as opposed to placing a desk or office wall right up against it.

What are the benefits of daylighting?

We've covered a lot of ground already, and you've probably got an idea of some of the main benefits, but let's take a look at some of the most important.

The main goal of daylighting is to decrease the need for artificial lighting and save on electricity expenses, as it can also cut down on heating, ventilation, and air conditioning (HVAC) expenses. While natural light may generate almost no heat at all when it is correctly managed, electrical lighting, as we've already touched upon, generates a lot of heat.

The overall energy savings for the majority of daylighting-integrated buildings range from 15 to 40%. Companies may first choose daylight for energy savings and sustainability reasons, but it can also affect the productivity and satisfaction of people who use the space, such as staff, students, clients, and retail customers.

Daylighting: Here's why natural light is the greatest tool of modern architecture
Daylighting has many benefits.

People are drawn to natural daylight and require daylight to stay healthy, both physically and mentally.

According to various studies, daylighting has a direct effect on happiness, productivity, and overall pleasure. Even big-box retailers like Wal-Mart have recognized the financial and environmental advantages of daylighting for both staff and customers.

In some other studies, stores that had skylights above specific departments discovered that the overall sales per square foot were greater in the areas with natural light.

But what are some of the main drawbacks of daylighting?

Even though daylighting can have a variety of good effects on employee performance, if a program is not effectively implemented, it can also have unfavorable effects. Facility managers can overcome the difficulties of daylighting by using a few tactics, however,

Initially, a high-performance daylighting system can require a sizable expenditure. However, if the project team adopts an integrated, strategic design strategy, a business's overall long-term savings outweigh any upfront daylighting costs.

Daylighting: Here's why natural light is the greatest tool of modern architecture
Good ue of daylighting can transfer a space.

Controlling glare is one crucial issue. Direct sunlight entering offices and schools frequently creates an uncomfortable glare on work surfaces, making it challenging to work or see a computer screen.

The optimal combination of light for a structure can be produced by properly oriented windows and skylights, which also help to reduce glare. The amount of light required should be taken into consideration while choosing and positioning windows and skylights, as well as the climate and architectural style of the structure.

Controlling the quantity of heat that enters a structure is also necessary for daylighting. Given how effective it is in lighting up structures, the sun can also generate a ton of heat. Utilizing natural lighting might provide unwanted heat gains if not planned appropriately.

It could seem challenging to boost light levels without producing additional heat. However, you can shade a window or deflect direct sunlight by using window treatments, window coatings, or glazing, which will reduce heat gain. As a result, there may be no need for a larger cooling system, which can further reduce overall cooling loads and save money.

Daylighting: Here's why natural light is the greatest tool of modern architecture
Daylighting has downsides too.

The use of daylighting tactics is not without its difficulties, such as excessive heat or light. Certain architectural elements, including a building's roof, the design of an atrium, or the angles of a building, might prohibit sunshine from illuminating an area. Wall openings in rooms should be arranged carefully to avoid blocking the daylight.

For instance, components that can block light should be placed as far away from wall openings as feasible if they are high up in the room. In a layout with both open and closed areas, the open areas ought to be near the wall openings. Reflecting light farther into the space amplifies the impact of daylight.

What are some advantages of daylighting for different sectors?

1. Daylighting is great for office spaces

Most people who work in an office tend to be under pressure from many directions. For example, they may be engaged in repetitive and boring tasks that can, and will, make them tired after working for a while.

Natural lighting in the workplace can lead to better health, fewer sick days, more work getting done, lower costs for the office manager, fewer accidents, better mental performance, better sleep, and higher morale.

2. Daylighting is also great for schools and other educational facilities

In educational institutions, both professors and students exhibit certain behaviors that are influenced by the amount of natural light in the classrooms.

Daylighting: Here's why natural light is the greatest tool of modern architecture
Daylighting can increase productivity and sales.

According to a 1998 study titled "Benefits of Natural Daylighting," higher student and instructor attendance, greater achievement rates, decreased weariness, improved student health, and enhancement factors of general student development are among the benefits of natural daylighting.

Natural lighting in schools has also been linked to physical growth, a good mood throughout the day, and higher levels of alertness and activity in students.

3. Daylighting has many benefits for the retail sector too

Allowing natural light inside stores has become increasingly popular recently because it improves the store's ambiance, boosts sales, makes the shopping experience more pleasant, draws consumers in, and enhances color rendering.

It has been demonstrated that natural light not only makes customers feel more welcome but also makes the store appear cleaner, brighter, and more open. In hospitals with enough natural light, the mental and physical stress on patients, doctors, and nurses has been shown to go down.

Retailers such as Wal-Mart, Target, and Recreational Equipment Incorporated (REI) in Seattle, Washington; Lamb's Thriftway Store in Portland, Oregon; and others have noted the advantages of natural lighting inside the store.

4. Daylighting helps boost recovery and well-being in hospitals

In hospitals, the patient's mental health is the most crucial aspect, and allowing for natural light and air has been shown to improve patients' mental condition and speed up their recovery. The mental and physical burden on patients, doctors, and nurses can be decreased in hospitals with sufficient natural illumination.

This has also made the relationship between the doctor and patient better and helped patients avoid depression or psychological stress after surgery. Anecdotally, an abundance of natural light may help people feel more spiritual, more open, and freer.

5. There are benefits for the industry as well

Industrial settings are typically related to a large extent to repetitive physical labor. Architects previously designed many industrial structures without many windows in order to keep dust out, but many people who worked in these windowless industrial settings suffered from problems like increased capillary permeability, inflammation, less white cell activity, and more catarrhal infections and colds.

Because this was bad for their health, workers were less productive, which caused an increase in business expenses. The employees of windowless businesses experience negative behavioral effects as well, including feelings of claustrophobia and discontent, absenteeism issues, and an increase in vandalism.

And that is your lot for today.

Maximizing the use of natural light within a building is a great way to reduce energy costs and make a space more welcoming for human beings. This has been shown to increase sales and workforce productivity and even improve building users' moods and overall mental health.

While there are also downsides, attention to detail when developing a daylight strategy really does pay dividends in the end.

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