Lighting is an important part of any building, but due to its energy-saving potential, it’s even more important in a sustainable building. But how do sustainable buildings take advantage of lighting?
Lighting in sustainable buildings is designed to lower energy use without compromising the comfort of the people in the building. Natural lighting, energy-efficient light bulbs, and lighting controls are the main ways in which lighting helps a building be sustainable.
This article explains what sustainable lighting is and the most common types of sustainable lighting. I’ll also explain the LEED lighting requirements that help make a building sustainable.
What Is Sustainable Lighting?
Before we get into how lighting is designed in sustainable buildings, let’s look at how sustainable lighting works and what some of the goals it aims to achieve are.
Sustainable lighting is lighting designed to use the least amount of energy and last the longest time possible without needing replacements. It also doesn’t contribute too much to light pollution and avoids harmful chemicals in light bulbs.
Low Energy Consumption
Before anything else, sustainable lighting should reduce energy usage. Inefficient lighting uses more energy and has a larger carbon footprint.
For a building to be sustainable, it needs to have a low impact on the environment, and one of the best ways to do that in regard to lighting is keeping it at a minimum.
Besides being environmentally friendly, low energy consumption also can drastically reduce energy bills.
Low Light Pollution
Furthermore, you do not want the lighting to be at such a high capacity that it impacts the people in your building and the people in the surrounding buildings. You want enough light for the inhabitants to be comfortable, but not so much that the lighting is overwhelming and distracting.
High light pollution is also harmful to any wildlife around the building and will deter it from staying in the area.
Low Use of Chemicals in Lighting Products
Another characteristic of sustainable lighting is that it releases very few chemicals, if any at all. Lighting in a sustainable building should not release chemicals into the air.
Part of the responsibility for this falls on the lighting manufacturer, while another part falls on the architect and the construction company responsible for choosing the lighting that goes into the building.
Manufacturers should be doing their best to produce sustainable lighting, but the building designers should also go out of their way to choose lighting that isn’t chemical-heavy.
As sustainable lighting becomes widespread and the demand for high-quality, sustainable lightbulbs increases, manufacturers will be inclined to make more affordable products.
Some examples of harmful chemicals in lightbulbs, such as LED bulbs, are copper, lead, and other heavy metals. These chemicals can be released from the lights over time and be harmful to the people in the building.
When the bulbs burn out and are thrown away, they will continue releasing toxic chemicals into the environment and landfills unless disposed of properly.
Long Durability and Low Maintenance
Sustainable lighting should last for as long as possible and require minimal maintenance. Low cost is one of the most important factors of sustainable lighting, and reducing the number of lightbulbs that need to be bought certainly brings expenses down.
Certain light bulbs are more efficient than others and last much longer. Choosing these types of bulbs is a great way to maximize the lifespan of the lighting without sacrificing energy efficiency.
For example, high-quality LED lights can last over 20 years, although if the lightbulb is exposed to a lot of heat this period will be significantly shortened.
And not only should the lifespan of lightbulbs be long, but it should remain sustainable as technology improves. When choosing lighting equipment for a building, it’s a good idea to go for the newest technology so it doesn’t fall too far behind the standard for sustainable lighting as time passes.
Types of Sustainable Lighting
Now that we know what sustainable lighting is, we can look at the types of sustainable lighting and how they are incorporated into sustainable buildings. Sustainable lighting falls into three major categories:
- Natural light
- Sustainable light bulbs
- Sustainable lighting controls
This section explains the key elements of lighting that any sustainable building needs to take into account.
The first type of sustainable lighting is natural light. Using natural light does not require any energy use and is better for us as humans in terms of health and comfort.
If you want natural light to be a big aspect of a building’s design, you need to carefully plan the location of windows and other ways light enters the building.
Depending on where they’re placed, windows can bring specific benefits. Here are the ways different types of windows bring in natural light:
- North-facing windows: North-side windows are great for daylight because they let in a lot of natural light and don’t get too much heat in the summer. However, they also don’t get much sunlight in the winter, and heat from inside the building is most likely to leave the building through the windows in the north.
- South-facing windows: South-facing windows need overhangs that keep out direct sunlight and too much heat in the summer, but the inside of the building will still receive plenty of light. These windows will let in plenty of light and heat in the winter.
- East and west-facing windows: These windows provide light in the morning when the sun is rising and in the evening when the sun is setting. However, they’ll also get hot in the summer during these times of the day.
There are pros and cons to each window placement. The heat in the windows during the winter is helpful for keeping heating costs down, but in the summer they can increase cooling costs.
Sustainable Light Bulbs
Of course, natural light can’t be the only kind of sustainable lighting in a building. You need lighting during the night and some rooms, particularly in the middle of a building, can’t get lighting from the outside.
There are three main types of sustainable lightbulbs, all of which have their benefits:
- Fluorescent lights: Fluorescent lights are a good option if you want something that uses less energy than traditional incandescent bulbs but still produces the same amount of light. A huge benefit of these lights is that they last up to ten times longer than traditional ones. There are large, long fluorescent lightbulbs for office and commercial buildings and compact ones for homes.
- Light emitting diode (LED) lights: LED lights are the most common type of sustainable lighting. They only use one-fourth the amount of energy as incandescent lighting and release almost no heat when they are lit. They last 25 times longer than incandescent lights, so building designers often pick them over fluorescent lights.
- High-intensity discharge (HID) lights: Finally, HID lights are the most efficient type of sustainable lights—they can save up to 90% of the energy used by traditional incandescent lights. They produce intense amounts of light, but they also take ten minutes to be fully on. HID lights are best for places that stay lit for prolonged periods.
These are all good types of lights that you can implement in a sustainable building. However, HID lights don’t work as well with sustainable lighting controls as they wouldn’t turn on fast enough to work effectively with the rest of the system.
Sustainable Lighting Controls
The third ingredient in sustainable lighting is sustainable lighting controls. These can help save immense amounts of energy by controlling when lights are on and off.
The most common example of lighting controls is those that use presence sensors. These sensors turn on the lights when they detect movement and turn them off after they don’t detect any after a certain amount of time.
These lighting controls reduce reliance on people remembering to turn off lights when they leave, even if it’s just for a little while.
You may now understand why HID isn’t a great fit for these types of controls. Once they turn off, HID bulbs will take ten minutes to turn back on when a person enters the room.
However, there are other types of lighting controls, such as timer lighting, with which HID lights and other lights can work. These are great for outdoor lights that stay on during the night. You can set them to turn on when the sun sets and then back off in the early morning.
A similar type of lighting control is daylight sensors. When these sensors stop detecting sunlight, they turn on the lights. Sometimes these are paired with solar panels, making them even more energy efficient.
Sustainable buildings benefit the most from lighting controls when they integrate several different types of sensors. Luckily, modern lighting systems are easily integrated into some kind of software, making things easy to manage and modify depending on the time of year.
Another perk of having a smart lighting system is being able to dim excessive levels of light in order to reduce glare and give a better experience to those inside the building.
LEED Lighting Standards
LEED is a certification that buildings can earn depending on how sustainable they are. Points are awarded based on different sustainability practices implemented in the building.
Buildings get a rated certification—the more points, the better. One of the ways a building can earn points is by having sustainable lighting, specifically in the “Interior Lighting” category.
Whether or not you are going for a LEED certification for a building, following the guidelines is a great way to ensure the building is designed for sustainable lighting. This category’s goal is to provide efficient, high-quality lighting and promotes the productivity and comfort of the people who occupy the building.
There are four subcategories of interior lighting in the LEED guidelines. The more you achieve within a building, the more points you receive. Here are the four LEED interior lighting categories:
- Glare control: Light fixtures need glare control, which limits lights from being too strong for the inhabitants of the building. Lighting needs to have a luminance under 7,000 candela per square meter or a Unified Glare Rating of under 19.
- Color rendering: There also needs to be some color rendering in indoor spaces: a Color Rendering Index of 90, a Color Fidelity Index over 78, and a gamut index between 97 and 110. Color rendering refers to how well a light fixture reflects the colors of objects when compared to natural light.
- Lighting control: Lighting controls, as discussed above, need to be in at least 90% of spaces in the building.
- Surface reflectivity: There should be ceilings and walls that reflect light in at least 90% of the regularly occupied spaces. For the walls, the surface reflectivity should be 55%, and for ceilings, it needs to be 80% or higher. The reflectivity keeps the lighting from overwhelming people in the room.
Lighting Design Software
A key aspect of sustainable lighting is knowing where to place light fixtures in the most efficient way possible. This means knowing which placements will better illuminate an area, taking into account things such as surface reflections and the interactions between artificial light and natural light.
For this purpose, architects and designers take advantage of lighting software. These programs allow you to render lighting inside a 3D model of the building and provide information on the levels of intensity and other qualities of the light.
Some of the most popular programs used for lighting design are:
- Autodesk Maya
Three main lighting types are implemented in a sustainable building: natural light, energy-efficient light bulbs, and lighting controls. All these factors help make a building sustainable by saving energy and keeping lighting costs low.
They should also last a long time, which means buying fewer lightbulbs in the long term.
Lighting in a building should be comfortable for the people who occupy the building. Following LEED standards is a good way to get sustainable lighting on point.
- Building Green: Lighting Design for Health and Sustainability: A Guide for Architects
- Williams: Lighting
- Electrical Contractor: The LEED View: Sustainable Lighting
- University of Texas at Austin: Blog: Natural Light as a Tool for Sustainable Building Design
- US Department of Energy: Sustainable Lighting Design
- US Green Building Council: Interior Lighting