Lighting Fixture Products

types of lighting

Lighting has a significant impact on how a space feels enhancing either a work or relaxation space. There are three basic types of lighting that include ambient, task and accent.

Ambient (General) Lighting

All rooms need some general lighting to enable the occupants to get around without bumping into things. During the day, natural sunlight can provide most of the ambient lighting in a house with enough windows in the right locations. Lighting at night can be generated from direct or indirect sources, or a combination of both.

Whatever the source of ambient light, the amount needed is influenced by the colors in the room and their reflectivity. Ambient lighting provides the overall illumination that eliminates unwanted areas of darkness and balances the brightness of the task and accent layers. Since ambient lighting covers many of the work surfaces in a space, it contributes to task illumination, but is seldom sufficient to achieve recommended foot candle levels. In kitchens, overhead ambient lighting also provides illumination for visual tasks inside upper cabinets and for cleaning the floor.

Task Lighting

Primary tasks in most homes occur in the kitchen and bathroom areas which makes task lighting particularly important. This type of lighting is utilized for activities such as reading, writing and preparing meals or when general lighting of a room is just not enough. The term “task lighting” refers to lighting directed principally to illuminate work surfaces or support visual focus on a specific task whether from overhead or under cabinet luminaires.

For the recommended range of illuminance (fc) for different tasks. Both the NKBA and IES agree that 50 (fc) is the minimum amount of light to be delivered to a work surface for clients between 25 and 65; with clients over 65 needing twice that, or 100 (fc).

Task Lighting Categories

The IES will soon release a new Fc/Lux conversion. The current ratio of 1:10 ratio will change to 1:10.76. This new conversion of 1:10.76 is reflected in the table noted above.

Task Visibility

Think of a basic kitchen task, such as reading a recipe from a cookbook while cooking. Open the book to the recipe and place it on the counter.

• The pages are white paper; the print is black ink. The contrast is quite high, which makes the text stand out.
• The text is set in 12-point type of a comfortable font design, and you are viewing from about 20 inches away (distance from eye to page). Together, these factors determine the “visual size” of the task, which appears large enough that you do not move closer.
• You are in the midst of preparing a dish on the nearby range and forgot exactly in what order to add some ingredients to the fast-cooking food. So you are pressed for time and need to speed up your reading, which seems harder than you would have thought. You turn on the light
• Your mother walks over to help out. Finding it difficult to see the task at her age, she turns on additional light.

You have just considered three of the key factors affecting task visibility:

• Task contrast
• Visual size
• Luminance

Task Contrast

Task contrast is the difference between the reflectance of the task and that of its background. The bigger the difference, the higher the contrast and the better the visibility.

Printed text on a page or label is an obvious example, generally, of high contrast. Here are some others:

• Dirt on a countertop or the floor
• Food stuck on a utensil or pot
• Food sautéing in a pan
• Solids dissolving in liquids
• Blemishes on skin
• Images in a photograph
• Text from a printer
• Broken china on the floor or counter

Contrast also characterizes materials with different colors, what is called color contrast. A green bowl will stand out in a dark wooden cabinet (about the same reflectance), where a wood bowl will be harder to see.

Visual Size

As noted in the cookbook example, visual size combines the actual size of the task and the distance from which it is viewed. Bend over the cookbook, and the text appears larger. Notice how close you hold a box of food to read the ingredients.

If you want to pick out a mug from a cabinet shelf, the relevant size is the form of the mug (as opposed to a glass, for example). However, if you want to pick out a mug with a particular saying printed on it, the relevant size is that of the print. (Note that mugs of different colors are very quickly distinguished.)

Luminance

Simply put, luminance is the brightness of the task seen from our point of view. Understanding luminance as a concept helps us to understand and apply light more effectively, even if we do not commonly use the term in everyday work.

Importantly, luminance is not the same as illuminance, which is the light arriving at the task measured in footcandles or lux. Although you can measure and calculate luminance, we rarely do so in residential applications.

Technically, luminance measures the strength of light coming from an object, as seen from our point of view. Luminance represents light reflecting off or transmitted through an object in the direction of our eye. Thus, luminance involves the source of light, the task, and the eye, and how they relate to each other. The luminance of a light source that is intrinsically luminous does not depend on the task.

Accent Lighting

Accent lighting, like focal light illuminates objects to draw attention to them. In order for lighting to accent or highlight an object, it must increase its brightness significantly, three to five times compared to the surroundings. Accent lighting also can be used to highlight architectural details of a space. An example may be cove ceilings or tray ceilings. In this case, the brightness does not have to be three to five times brighter than the rest of the space. This type of accent lighting results in a nice aesthetic and brings attention to architectural types of details.

Layers of Light

In terms of lighting, layering both describes the luminous experience and helps to analyze its design. The visual experience of layering is more metaphorical than visual: It is more like tasting complex flavors, smelling a blended aroma, and hearing harmonies than seeing a physical or geometric arrangement. The layers of lighting both combine and stand out, creating a subtle and rich visual experience.

Layering also provides a practical approach to analyzing the different effects of a lighting composition. The language of lighting layers helps to deconstruct a lighted space that someone is standing in to understand how it works.

Richard Kelly (1910–1977) was the lighting designer responsible for some of the most widely used language of lighting and is considered one of the pioneers of architectural lighting design.

Layered lighting effects can be experiential and include:

• Focal
• Ambient
• Sparkle

Or they can be functional (note some similarity) and include:

• Ambient
• Accent
• Task
• Wall
• Decorative

We explore both sets of terms because each offers a different but useful approach to seeing and communicating lighting.

Experiential Layers of Light

Here is how Richard Kelly described the layers of light in “The ABC of Lightplay at Home” (1957): “A is for the Attraction of Focal Glow. B is for the Background of Ambient Luminescence. And C is for the Charm of a Play of Brilliants”.

The ABC of Lightplay at Home.

Note that Kelly describes the light experienced, not the lighting being applied. In the discussion that follows, we begin with Kelly’s description and then suggest how the effects can be achieved.

Focal Light

The term “focal light” describes the concentrated beam that illuminates the object and creates the glowing effect. Focal light supports the human propensity to focus on what is brightest in our surroundings. Objects need to be three to five times as bright as their surroundings in order to draw attention and perhaps ten times as bright in order to command attention.

Objects in museum galleries, retail displays and theatrical presentations demonstrate the pull of focal glow. The term “focal glow” describes an object brightened by a beam of light—a vase of flowers, for example—or an object luminous in itself—such as a table lamp with a diffusing shade. Both stand out and draw attention. Kelly wrote about the effect of a beam of sunlight on a shaded pathway as an example from nature.

Ambient Light

According to Kelly, ambient luminescence describes the background brightness that orients people to and through a space, offering a sense of security and comfort. As mentioned previously, ambient light, fills a space, eliminating the unintentionally dark areas that would (by virtue of their contrast) otherwise call for attention.

The comfort of ambient light arises both from the absence of disturbing and potentially dangerous areas of darkness and also from reducing adaptation to wide variations in brightness. As an experience, ambient light need not be completely uniform; some variation is almost unavoidable. Consider how difficult it is to achieve uniform brightness in an environment with surfaces of varying reflectance. More important, perfectly uniform brightness can feel disorienting as it diminishes the spatial and visual hierarchies in the built environment (think of a room with uniformly white surfaces).

Sparkle

What Richard Kelly called “the play of brilliants” we know as sparkle. We recognize sparkle in the crystal pendants of a chandelier, the light glinting in a wine goblet, the twinkling of holiday lights against an evergreen, sunlight reflecting off wavelets in a wind-brushed lake or light captured by droplets of water after a spring rainfall. Poetic references to sparkle are appropriate because of the special emotional effect produced by this quality of light. Think of holiday and celebratory experiences and the sparkle in the lighting effects.

Functional Layers of Light

According to Kelly, functional layers of light are often related to specific luminaires. Unfortunately, this shortcut may make it difficult to envision the lighted quality of the space (as opposed to the equipment in it) and may lead to confusion when trying to develop lighting from concept to a fully specified design. Lighting that illuminates the periphery of a space significantly affects our sense of spaciousness and relaxation. So, it makes sense to devote a separate layer of lighting to the periphery.

Since both cabinetry and appliances fill the majority of space in a kitchen wall exposure is usually limited. In busy areas such as a kitchen, ambient lighting provides the layer that illuminates the exteriors of most cabinetry. Accent lighting utilized in a kitchen space can be achieved by creating an accent layer by drawing attention to glassware or elaborate china.

Nevertheless, the wall layer reminds us of the importance of this peripheral lighting function in the lighting composition. It is important to be able to prepare meals and cook in the most efficient way possible and task lighting offers this functionality. Even the best under-cabinet lights alone are not effective at delivering 50 to 100-foot candles at the front edge of the counters. However, they help to provide a soft low-key illumination that many prefer for night lighting.

In an arrangement of otherwise functional layers, decorative lighting provides light from lighting equipment that offers a dominant glow or sparkle effect. Some applications, such as a guest bath, often use decorative wall sconces to establish a design theme or simply to impress visitors.

The functional layers of light guide us in thinking about what lighting should do: illuminate tasks, provide comfortable ambient illumination, accent special objects, brighten walls, and decorate a space with luminous objects. In this sense, the functional layers are analytical; they can be recognized most easily by identifying the luminaires associated with each layer. That is both the strength and weakness of this approach. Distinguishing which layers of lighting are needed when provides control to each layer separately and operate it only when it is needed.

Reflected Light and Surfaces

Recall that light flows invisibly from its source to a surface. Once light reflects from or transmits through a material, our perception inextricably combines the light and the material. Therefore, to understand the appearance of light, we must look directly at the source. When light strikes a surface, some is absorbed. The lower the reflectance of the surface, the higher the absorption of light which means less light ultimately reaches its target. Dark stone and highly textured surfaces, for example, can trap light. Since these low-reflectance materials can be an important part of interior design, there is a trade-off between visual and environmental impact.

Reflective Finishes

Reflective finishes help to transfer daylight from its source, for example a window, deeper into the space. Lighter colors on a ceiling plays a particularly important role. A high-reflectance white ceiling with a light reflectance (LR) value of 0.90 means that 90 percent of the light beam that strikes the ceiling will be reflected, regardless of the light source. High-reflectance finishes brighten interior surfaces, creating secondary sources of daylight that will soften shadows.

Glossy (specular) surfaces or mirror-like surfaces, reflect light at the same angle as it arrives. The angle of incidence equals the angle of reflection. Glossy finishes reflect light in a precise way, creating a clear reflected image in the surface when viewed from a particular direction. From other directions, no light is reflected, and the surface appears dark. Overhead lighting reflected in a bathroom mirror or lighting reflected in a polished countertop are common problems encountered with glossy materials.

In contrast, matte (rough) finishes offer nearly zero reflectivity, such that no image is visible. Walls finished with a matte (flat) paint and surfaces with matte-finished laminate provide a soft and image-free appearance.

Reflecting Surfaces

Since daylight originates well above the ceiling plane, how does daylight reach the ceiling? Daylight first reflects off of the exterior ground, deck, patio or garden and then reaches the interior ceiling. Daylight also can reflect from interior horizontal surfaces designed to transfer back into the space.

Glare is when bright light is directed or reflected toward the viewer, causing discomfort of the eye. This can be the result of light reflected off a shiny (specular) surface. The direction of the light and where it originates relative to the task is a major problem, particularly at kitchen counters. Light that originates in front of the task and reflects toward the eye can create reflected glare and veiling reflections. Reflection is light bouncing off a diffuse (rough) surface or specular (smooth) surface. Reflected glare is excessive, distracting and uncomfortable brightness reflected toward the eye.

Older adults are particularly sensitive to glare. Where possible, provide natural light from at least two directions, as light from a single wall can create a “cave” effect. Diffused reflection eliminates glare whereas specular reflection can cause glare. The term “veiling reflections” refers to light that reduces task contrast.

Both reflected glare and veiling reflections are due to the location of the light source and the direction from which the light flows. Both problems are exacerbated by specular finishes on the task or in the task area. Position lighting equipment in task areas properly to resolve these challenges.

Lighting Controls

Electric lighting is static, until controls are added. Controls allows lighting to vary in order to suit the task, create a mood, reduce energy and maintenance costs or simply to make life more comfortable and convenient. All lighting requires control. Every light in a space can be turned on or off by toggling a single switch up and down. The room is either flooded with every available foot-candle or it is totally dark. More effectively, each layer of light is controlled by a dimmer, permitting the client to balance the brightness among the layers, tuning the overall lighting effect for the various activities, moods and people in the space.

The dimming first of fluorescent and more recently of LED sources has added considerable technical challenges to the delivery of consistently satisfactory results. Nevertheless, the combination of digital lighting (LED) and digital control (particularly wireless control) promises to make lighting more responsive to users than ever before. This rapidly changing field often makes it difficult to incorporate products and techniques from different manufacturers into a design, so always remember to follow a manufacturers compatibility recommendation. Also consider partnering with a competent low-voltage integrator. The following offers generic terms used for control systems.

Rapidly Changing Field

The field of controls is changing rapidly, perhaps with even more impact than evolving LED (light-emitting diode) technology.

The dimming of theatrical lighting began in the first third of the twentieth century, more than 75 years ago. The earliest dimmers simply shunted some of the power away from the lighting, reducing light output but not the total amount of power consumed.

Modern control for residences began in the 1960s with the introduction of electronic circuits into wall box dimmers. By the 1990s, residentially scaled dimming systems made theatrical effects possible in the home. With the introduction of networked and wireless controls, dimming control became more powerful and convenient.

The dimming first of fluorescent and more recently of LED sources has added considerable technical challenges to delivery of consistently satisfactory results. Nevertheless, the combination of digital lighting (LED) and digital control (particularly wireless control) promises to make lighting more responsive to users than ever before.

Control Concepts

On/off controls offer just one light setting, on. Variable controls might be two settings (high and low), three settings (high, medium and low) or continuously adjustable (typical dimmer). On/off controls are simpler and less costly to purchase and install while variable controls offer more choices.

Manual controls require the device to be touched each time it needs to be adjusted. “Touch here” might mean simply toggling the switch lever or perhaps pressing an application on a phone. Actually, touching each control individually can be cumbersome and time consuming. Collecting touch points into a single device or keypad can solve this problem.

Automatic controls mean that light responds to an external signal without a direct, manual intervention. Motion sensors and clocks are simple examples. Controls that respond to manual control of another system are a hybrid of manual and automatic. Perhaps the preference is to turn on the home’s lighting when the garage door opener is pressed or the lighting to dim when the television is turned on.

A network is a system of linked elements that responds in a coordinated fashion. In a three-way switch, a third conductor connects two switches, enabling them to both toggle the lighting on and off. In more sophisticated controls, devices are connected by communication wires or wirelessly so that instructions sent from one device can be followed by several devices at different locations. In addition, a device, dimmer or switch can be controlled from several locations throughout the home. Linking controls through a network significantly enhances the convenience of using the lighting system and thus increases its functionality.

 Lighting Controls

Control Specialized Terms

Load

The term load describes the lighting connected to a control. The load identifies the type of electrical device to be controlled (incandescent, fluorescent, LED light sources or a fan or shade) and the total wattage connected to the control (five 20-watt [W] lamps or luminaires represents a 100 W load). Both switches and dimmers are governed by load maximums. Although a switch generally can control a variety of light sources, and other loads, a dimmer (or variable control) typically must be compatible with the load it is controlling.

Channel or Zone

The terms channel (from theater and audio) and zone (from the heating, ventilation and air-conditioning field) refer to a group of luminaires or other loads controlled together. Channel and zone are essentially interchangeable in basic usage. Typically, each layer of lighting (downlights, pendants, under-cabinet task lights, etc.) should be a separate channel or zone, meaning that each layer is connected to its own control. This way, each layer can be adjusted independently.

Power and Signal

All electric lighting equipment requires power, which is supplied over the electrical circuits in the home. An electrical circuit is a closed loop consisting of conductors for electricity, loads that use the electricity, controls that switch or dim the loads and a protective device (circuit breaker) to guard against overloading and, hence overheating the circuit. Controls can be inserted within a circuit or, in the case of large installations (typically commercial), multiple circuits may be controlled as a single channel.

Circuit Facts

Circuits are sized by the protective device and measured in amperes (a 20-amp circuit). The installing electrician is responsible for ensuring that the conductors will not overheat before the protective device cuts off the power. That is, “undersized” conductors will not be protected by a higher-amperage protective device.

Residential lighting circuits consist of two conductors, the hot and the neutral, plus a ground. In many residential applications, the switch or dimmer is inserted only on the hot leg of the circuit, meaning the neutral is not connected through the control. A common way of expressing this is to say, “There is no neutral wire in the box” (meaning the outlet box into which the control was wired). As you will see, neutral connections are required for many advanced control devices. Circuits are not the same as channels or zones, although the term may be (incorrectly) used that way.

• The control operates on the electricity that reaches the load. (Sometimes this is clarified as a load controller.) But how do you tell the control what to do?
• In a simple dimmer or switch, the manual adjustment (moving the toggle lever or slider) opens the circuit (shutting off the lights) or signals the dimmer to adjust to a different level. Here the “user interface” and the load control are incorporated into one device.
• In more complex systems, the user interface and load control may be separate devices, with a signal between them. In some cases, the signal travels over the same electrical conductors that power the lighting equipment (a power line carrier system); in others, there are separate signal conductors or a wireless signal.
• The difference between power and signal is particularly important when considering sophisticated control systems and dimming LED or fluorescent luminaires.
• Remember that communication requires both a sender and a receiver. The sender and receiver must be compatible, and the signal between them must be clear and free from interference.

User Interface

The user interface is the part of the system that is touched or told what is wanted. It is where the command is entered either manually, automatically or by hybrid. The user interface can be the familiar toggle lever, slider bar or push-button keypad. Sometimes the user interface is integrated with the load control (the switch in the house); sometimes it is a separate device, such as a mobile phone, connected by a signal to the control.

Controller

A load controller adjusts the electrical input to the load and through this, adjusts the light output. This is the component that does the actual work of switching or dimming.

Switch

A switch is a simple on/off device. It works by opening and closing the electrical circuit to the controlled load. An electronic switch takes a signal from another device on the control system. Multiple electronic switches typically can connect using just one additional conductor, permitting multiple locations with simplified wiring. A relay is a switch controlled by a low-voltage signal, which relays the command from the manual or automatic input to the switch itself. Relays are used to control commercial lighting and residentially for window blinds and in some occupancy-sensing devices.

Dimmer

Wall box dimmers are installed in one or more outlet boxes, the same type of boxes used to install receptacles. Other types of dimmers, often called dimmer modules, are installed in a cabinet or dimmer rack, typically located in a closet or near the electrical service panel. Only the user interface, typically a keypad, is mounted in the space itself.

Preset

A preset is a command that can be activated with a simple action, such as pushing a button. The preset recalls the light level set each time the control is turned on or by pressing the preset button.

Scene

A lighting scene is a setting for light in a space, typically using multiple layers of lighting. Conceptually, distinct lighting scenes should support each different activity in a space. The more scenes needed, the more important it is to have a comprehensive system that allows for this.

Remote

A remote is a user interface that enables to signal the load control from a separate location. Technically, most keypads are remote devices, but typically they are just called keypads. A hand-held remote uses an infrared (IR) beam or a radio signal to communicate.

Dimmers and How They Work

Dimming depends on the load—that is, the source—being controlled. From a dimming perspective, several different loads are found in homes:

• Incandescent – These may be familiar line voltage types or low-voltage types operating on different types of transformers.
• LED – These can be dedicated LED luminaires or LED lamps designed to fit into incandescent fixtures. In either case, special drivers are required for dimming.
• Fluorescent – These can be dedicated linear or compact fluorescent luminaires or screw-base, retrofit compact fluorescent (CFL) lamps. In either case, special ballasts are required for dimming.

Dimming Incandescent Loads

All incandescent lamps perform about the same as they dim.

• Dimming Range – Incandescent lamps can dim smoothly to very low levels. A deeply dimmed filament appears as a barely glowing twig.
• Color – Incandescent light changes color, moving from white to a much warmer amber tone (from 2700 Kelvin [K] or 3000 K down to about 2200 K).
• Lamp Life – Incandescent lamps last longer when dimmed. Expected life of 1000 hours (less than a year in typical use) might double if dimmed by about 10 percent and quadruple if dimmed by 25 to 30 percent.
• Efficacy – Light output falls much faster than power consumption. For example, dimming power by 50 percent results in a drop of more than 75 percent of light (as measured). That is, incandescent sources are less efficient when dimmed than when operated at full output.

Different Dimmers for Different Loads

Incandescent loads fall into three basic types:

1. Incandescent, line voltage. Arbitrary (A) lamps, bulge reflector (BR), parabolic aluminized reflector (PAR), and basic decorative lamps are the simplest loads to dim and can be controlled with inexpensive dimmers.
2. Incandescent, low voltage with magnetic transformers. This application typically is found in many multifaceted reflector (MR) lights such as MR16 recessed downlights and linear low-voltage luminaires, such as cove or cable systems using MR16 or other 12- or 24-volt lamps.
3. Incandescent, low voltage with electronic transformers. This application is similar to other low-voltage types but is the more current transformer technology and is almost universal in track lighting today.

Incandescent dimmers use a high-speed electronic switch that turns lighting on and off 120 times per second (twice per cycle). The longer the lights remain off, the dimmer the lighting effect.

Forward-Phase Cut Dimming.

This type of dimming is often called by different names:

• Incandescent
• Triac (after the type of electronic switch)
• Forward phase (after the relationship of the switch to the electrical cycle)

These are simply different names for the same type of control.

Dimmers for low-voltage incandescent loads with magnetic transformers differ from the simple incandescent type because they need to cope with the current induced by the magnetic components in the transformers. They can handle ordinary line voltage loads as well and are a type of forward-phase control dimmer.

This type of control is typically called a magnetic low-voltage (MLV) dimmer. Because a magnetic transformer is an inductive load (the magnetic induces a current), these devices may also be called inductive dimmers. MLV and inductive dimmers often require a neutral connection, which ensures proper operation.

Diagrams of dimmers with and without neutral wires.

The inrush of current each time a forward-phase dimmer turns on causes problems for electronic transformers. As a result, electronic low-voltage transformers should be dimmed with reverse-phase dimmers, which allow the current to ramp up each half cycle.

Reverse Phase Cut Dimming.

A reverse phase dimmer is also called an electronic low-voltage (ELV) dimmer and generally requires a neutral connection.

Dimming Fluorescent Loads

Fluorescent lamps vary more than incandescent lamps in terms of dimming quality.

• Dimming Range – High-quality dimming systems can dim linear fluorescent lamps down to about 1 percent of light output. While these low levels are needed to create the perception of a dimmed environment, they carry a higher material cost to ensure consistent lighted results. Everyday dimming results in about 10 to 30 percent of light at the lowest setting. CFL lamps do not dim to as low levels as linear lamps. CFL lamps with integral ballasts have dimming issues of their own.
• Color – Fluorescent lamps do not warm in color as they dim, which is a very important difference from the dimming performance of incandescent sources. High-quality lamps are considered pretty stable in their color (although the change in the quantity of light can affect how we feel about the color).
• Lamp Life – Fluorescent lamps do not enjoy the extended life of dimmed incandescent lamps but generally maintain their rated average life. Improperly designed dimming ballasts, however, can shorten life.
• Efficacy – Fluorescent lamps remain highly efficient when dimmed.

The dimming of fluorescent sources is performed by a special dimming ballast. The dimming ballast has a unique dual function. It lowers the current through the electric arc to reduce light output; at the same time, it maintains a steady current to heat the cathodes for proper operation and lamp life.

Fluorescent dimmers signal the dimming ballast how to dim. In residential applications, the signal often is sent over the power line, using either two or three conductors. In commercial applications, the signal often travels over dedicated control wires (either an analog 0-10V or a digital signal), which tends to be more reliable, although the separate wiring adds cost.

Dimming LED Loads

As you might expect with a fast-evolving technology, the dimming of LED luminaires and lamps does not match the experience of dimmed incandescent or, by and large, the consistency of fluorescent.

• Dimming Range – High-quality LED luminaires can dim down to the 1 percent range needed for the best results. Other products—and LED lamps—do not dim as well.
• Color – Standard white LEDs do not change color as they dim. This is an important difference between LED and incandescent technology and is especially challenging where LED lighting is being used in place of incandescent. However, some LED lamps and luminaires are available with LED arrays that contain both white and amber or red LEDs. These arrays can dim to warm color. Such products may be valuable if you want to create the warm, glowing feeling associated with dimmed incandescent lighting.
• Lamp Life – Dimming generally allows LEDs to operate at a lower internal temperature, which has a favorable effect on life. However, if product life is limited by driver electronics, the impact on life may not be significant. (They still will last longer than incandescent lamps, of course.)
• Efficacy – LED luminaires and lamps remain highly efficient when dimmed (actually increasing slightly due to lower internal temperatures).
• Dimming Issues – Smooth dimming over a full range can be a challenge for LED lamps. Compatibility between the specific lamp and specific dimmer is critical, as is managing the load between minimum and maximum levels.

Dimming Drivers

Special dimming drivers dim LED lamps and luminaires. The dimming driver adjusts current and voltage to lower the output of the LEDs. Dimmers signal the dimming driver and tell it how to adjust the light output. Compatible dimmers are determined by the specific design of the dimming driver.

Dimming LED Luminaires

LED luminaires typically use dimming drivers either controlled over the power line by extra-low voltage (ELV) incandescent dimmers or controlled by separate signal wires. (These may be the analog 0-10V signal or a digital signal such as DMX 512, a theatrical protocol often used for colored lighting.)

LED lamps with dimmable drivers rely on power line dimming control, either ordinary incandescent (forward phase) or ELV (reverse phase). Assuring compatibility between the specific LED lamp and the dimmer type, model, and manufacturer is critical to achieving satisfactory performance. To reduce the risk of problems, consult the compatibility charts published by both lamp and dimmer manufacturers and observe their load limits.

Choosing Ballasts and Dimmers

For pin-based fluorescent lamps, linear or compact, you specify the dimming ballast, which is supplied with the fixture, and the control. Fluorescent dimmer and dimming ballast must be compatible.

For retrofit CFL applications, you specify a dimmable lamp. Most of these are designed to dim on standard incandescent, forward-phase dimmers, although better results may be obtained with special CFL dimmers.

There is a multitude of dimmer styles, offering a variety of features from basic to sophisticated.

Sliders, Knobs, Toggles, and Rockers

You can set the dimmed light level using a variety of devices. Although they all perform the same function, they differ in style (contemporary to traditional) and ergonomic ease of use.

All dimmers today use electronic circuits. Most use an analog control; the farther you move the control, the more you dim. Digital dimmers convert taps or pressing into discrete light levels.

• Slider dimmers are easy to grasp and move, and their location on the dimmer back plate suggests the setting.
• Rotary dimmers provide a knob to set the light level. Some older clients may find that gripping the knob is not as easy as moving a slider, and it is difficult to read the setting from the position of the knob.
• Toggle dimmers look like toggle switches, which is their chief attraction. Due to the small size of the toggle, these types are not recommended for older clients.
• Rockers (sometimes called paddles) usually indicate that the setting is digital. Different taps, or how long you press the rocker, tell the dimmer how to set the light level. Rocker dimmers also match the appearance of rocker switches. Rockers are easy to touch, but their operation is not obvious to many people, making them hard to use in practice.

Preset Dimmers

As discussed earlier, a preset dimmer turns on to a previously established setting. This is a very convenient feature, useful in most applications. Preset sliders have a separate switch. Rotary dimmers typically push in for on/off control. Digital dimmers have a set button to create the preset level.

Smart Dimmers

Smart dimmers are dimmers that can retain multiple settings and respond to networked keypads as part of a system. Smart dimmers offer a simple and inexpensive approach to system control.

Smart Dimmer. Courtesy of Lutron.

Illuminated Dimmers

How do you find a dimmer (or switch) in the dark, especially if you unfamiliar with the room?

Some dimmers offer a lighted model that glows when the dimmer is set to off. Digital dimmers often use LED indicator lights to show the current and preset levels. (The rocker does not tell you, of course.) The indicator lights also help you locate the control.

Lighted dimmers can either be friendly convenience or an annoying distraction in the dark. Find out your client’s preference.

Sensors and How They Work

Sensors detect activity in the environment and signal lighting to respond by turning on, turning off, or changing output.

The two common types of lighting sensors include:

1. Motion sensors, to turn lights on or off, based detecting people in the space
2. Photo sensors, to switch or dim lighting, based on the amount of daylight detected by the sensor

Sensors have seen little application in residential kitchens and baths, but they play an increasingly important role in commercial control strategies. Some state building laws have mandated the use of sensor switches in residential bathrooms. As residential users grapple more with issues of energy and convenience, sensors can be expected to appear more often in home applications.

Motion Sensors

Motion sensors, sometimes called presence detectors, save energy by switching lighting off when no one is present (i.e., when the sensor does not detect any motion in the space). They also offer convenience and a sense of security by switching lighting on when the sensor detects motion (avoiding the need for the person to reach around in the dark).

Motion Sensor. Courtesy of Lutron.

Detection by Passive Infrared Technology

The simplest, most common, and least costly motion sensor consists of a grid of small-scale thermal detection cells that receive infrared radiation from warm objects—like human beings. At any moment, the grid of cells records a pattern, the thermal image of the space within the detection range.

When something warm—like you—moves, the thermal image changes. The sensor interprets the change as presence in the space. When the thermal image remains static for a period of time, the sensor interprets the lack of change as a lack of presence in the space. We discuss how the sensor instructs the lighting to respond under “Sensor Response.” follows.

We call this type of sensor “passive infrared” (or PIR) because it passively receives infrared radiation. Note that PIR sensors require a clear line of sight to the space. Blocking a sensor (as with a door or by moving a cabinet in front of it) cuts off the IR radiation so that there is no change in the thermal image, and the sensor “thinks” that the space is empty (whether it actually is or not).

PIR Sensor. Courtesy of Lutron.

Detection by Ultrasonic Technology

An ultrasonic detector emits an inaudible pressure wave (“sound” you do not hear) and then detects the reflection of the wave in its grid of cells. The sensor interprets a change in the detected pattern as motion and no change as presence.

The emissions from ultrasonic sensors can travel around partitions, even around corners, so this type of sensor does not need line of sight to the space—an advantage over PIR sensors in some applications.

However, any motion—wind rippling window blinds, for example—appears as human occupancy in the space, which is a disadvantage.

Dual Technology Sensor

A dual technology sensor combines PIR and ultrasonic detection, avoiding the pitfalls of each technology (at a higher cost).

Sensor Response

Motion sensors respond in two basic ways:

1. Auto on/auto off -When the sensor detects presence, it turns lights on and keeps them on until it no longer senses presence. After the sensor no longer detects presence, it signals the lights to turn off. Sometimes called an occupancy sensor, this control provides both the easy on for security and convenience and the easy off for energy savings.
2. Manual on/auto off – Once you turn the lights on yourself, they stay on as long as the sensor detects presence in the space. After the sensor no longer detects presence, it signals the switch to turn off. Sometimes called a vacancy sensor, this control maximizes energy savings because lights go on only when you want them on (permitting you to walk into a room without having lights switch on automatically).

Note that both types of sensors detect in the same way; only their response differs.

Sensors can be designed (and programmed at home) to respond quickly when motion is no longer detected or to wait a while before acting. This is called the time-out period. Waiting longer (15 to 30 minutes) allows more opportunity for the sensor to detect motion—a friendlier approach than snapping lights off after just a few seconds. (Waiting longer comes at the cost of slightly higher electricity bills.)

Photo Sensors

Photo sensors detect light using a receptor cell of light-sensitive material. Photo sensors are widely used to control outdoor lighting. (A weak reading in the cell signals the switch to turn on; a strong reading signals the switch to turn off.) Indoor usage is growing in commercial and institutional applications for daylight harvesting and balancing.

Daylight harvesting is a strategy for reducing energy consumption with automatic control by reducing electric light when daylight is available. Daylight balancing is a strategy for improving the experience of a transition space by increasing electric light to balance daylight at the perimeter of a space. While these automatic control strategies are not widely used in homes, it is worth understanding their objectives and how they work.

In a daylight harvesting scheme (imagine an office or classroom), the photo sensor reads the combined effect of daylight and electric light in the space. A controller sends a dimming signal to adjust the electric light to maintain a target level of illumination. The electric light dims when daylight is available and increases as daylight diminishes. (Perhaps you noticed that, notwithstanding the name, it is the electric lighting that is being harvested.)

In a daylight balancing scheme (imagine a lobby or boutique exposed to plenty of daylight), the photo sensor reads exterior daylight only. When the reading is high (bright daylight), a controller raises the level of electric light so that the interior does not feel so dim in comparison to the bright exterior. As daylight fades, the interior lighting dims so that remains at a comfortable level.

Smart Technology

Let’s consider how controls can be linked or networked to increase functionality and convenience. A control system is the term commonly used to describe linked controls. Systems can range from a group of smart dimmers that all respond to keypad commands, to LED lamps that can be controlled by a wireless signal from a smartphone or tablet, to a fully integrated home automation system. Making it easy to adjust lighting effects to a desired setting is what a system (rather than stand-alone controls) is all about. Generally speaking, the more things the controls needs to do, the more costly the system will be to purchase and install.

The newest form of controllable lighting features wireless control of one or a group of special LED lamps. Using an ordinary wireless Internet router and a proprietary hub, controlling these special light sources can be made from a smartphone, tablet, IoT interface, voice-activation module or a dedicated remote. Any portable or fixed luminaire with a medium-base socket can be fitted with these lamps, which typically pass the wireless signal from receiver to receiver, allowing the control to span an entire house.

Smart home technology is not just limited to LED products, but can control any electrical component in the home. Many homes today integrate these interfacing features to make life easier and more efficient for the homeowner. As more and more smart home technology options become available for lighting the kitchen and bath designer should stay current with the changing times. There are two paths a designer can consider:

1. Self-Education – The designer can independently acquire the knowledge to plan a smart home. Tools for that are being developed by the NKBA and are already available elsewhere.
2. Partnering with an Expert – Locating a local expert could be a viable solution. An electrical systems integrator can be of assistance for technological, security and data communication systems throughout the home. CEDIA is also a professional organization with members nationally who have a comfort with many forms of smart technology. Reaching out to them may provide the designer an easy answer to a complex question.

Control Systems

Making it easy to adjust lighting effects to your desired settings is what a system (rather than stand-alone controls) is all about. Do you want to link just the controls in the kitchen, or would you prefer to connect controls for kitchen lighting to a keypad at the main entry?

Scope—room or house—is the first question to answer in thinking about systems. Generally speaking, the more you want your controls to do, the more costly the system will be to purchase and install. It is not surprising that systems limited to one room tend to be simpler and less costly than those connected throughout the home. But whole-house controls can offer significantly greater convenience, including the ability to turn all lights off when leaving, to turn on a “welcome path” through the house when entering, or to set a “return” setting so that you do not enter a darkened home.

Systems for Single Rooms

Imagine an ordinary kitchen. The kitchen opens to a pantry with its own ambient lighting as well as to the dining area and to the main entry hall, three points of entry altogether. The principal activities include food preparation and cleanup, breakfast at the table, coffee or a late snack at the peninsula, and home office work both at the table and peninsula.

Kitchen Plan Design by Kim Van Ruskenveld, AKBD, Design Eye Ltd., Edmonton, AB.

The Kitchen

Your lighting design provides task lighting over the countertops, pendants over a breakfast table and peninsula, and ambient lighting throughout. To meet the lighting needs of each activity, you provide a dimmer for each of the four lighting layers. Now, each time the kitchen is used, your client needs to find the correct dimmer for each type of lighting and adjust it as desired.

Kitchen plan—lighting and basic control Design by Kim Van Ruskenveld, AKBD, Design Eye Ltd., Edmonton, AB

Making Controls More Convenient

Wouldn’t it be easier to adjust all of the lighting once for each activity (create scenes), and then simply press a keypad button to recall the appropriate scene? Wouldn’t it be nice to neatly label the buttons so that guests can use the kitchen when you are not around? And wouldn’t it save time and frustration to place keypads at each of the three entry points so they can be reached regardless of how you are moving through the house? That is exactly what a system does for you!

System Design

This simple system uses four dimmers (one for each layer) and three keypads, one for each entry. Each keypad has five buttons that can be customized by name, such as “Coffee,” “Breakfast,” “Dinner,” “Homework,” and “Off”—one for each scene.

Programmable Keypad. Courtesy of Lutron.

Each button tells all four dimmers to recall the specific setting that is part of the scene you want to create. A network signal wire or wireless transmitters and receivers might be used to connect the components to each other.

The dimmers can be ganged together in one location or distributed so they are near the lighting they control. Ganging often looks cleaner. Distributing makes it easier to temporarily override any scene to make a lighting layer brighter or dimmer.

Wireless communication is much more flexible than wired connections and allows for less costly remodeling. (There is no need to run new signal wires.) But wireless carries a higher price and, depending on product quality, may be less reliable.

To determine what kind of system suits the project, you have to have an idea of what is required. Following are some points that must be considered.

• The number of dimmers depends on the number of lighting layers and control channels you want.
• The number of keypads depends on how many control locations you want.
• The number of buttons on the keypads depends on how many different scenes or settings you want.

The Bath

Although many bathrooms are simple enough to light and control with two or three stand-alone devices, other spaces are larger and benefit from a control system. These spaces host a wide variety of activities, ranging from routine grooming, to luxuriating in a spa, to exercising. Multiple layers of lighting, each independently controlled, support the diverse activities and client preferences.

Bathroom Lighting Plan and System. Design by Nicole Campbell, Design Eye Ltd., Edmonton, AB.

The same type of system and design approach sketched for our kitchen works in this larger and more complex bath area.

Controlling Adjacent Spaces

The preceding examples focused on self-contained spaces: single rooms. Room control systems can extend to control adjacent areas as well. A kitchen might open onto the dining area without intervening walls; the pantry might be an alcove off the main kitchen space; the bath might be en-suite to the principal bedroom or dressing area.

In these cases, you need to consider systems offering greater flexibility in the number of dimmers, keypads, and buttons. Conceptually, however, designing controls and settings is the same process.

Systems for the Entire House

You typically control a single-room system from within the space or from a visually connected adjacent space. To control more than one room and to control spaces from remote locations (such as the front or rear doors, a different floor, or the master bedroom), you want to use a system designed for an entire house.

For house control, you begin with a control (switch or dimmer) for each lighting layer. As with room control, these controls are then connected to keypads that control one or more switch or dimmer. As with single-room systems, the connections can be wired or wireless.

Some manufacturers offer products that can be used to control either a single room or an entire house. These products can simplify design, installation, and troubleshooting.

Strategies

Systems for controlling an entire house are very powerful. You need to decide what you want the system to do; otherwise, it can become burdened with more cost and complexity than is really needed. Some strategies are listed next.

• Entry and Exit – Arrange controls to turn on selected lights in specific rooms to provide a comfortable and secure entry. Turn off all lights upon leaving. Or turn off most lighting and leave security lights on.
• Paths of Light – Arrange controls to turn on a path of light from one area of the house to another (e.g., entry to kitchen or bedroom or master bedroom to kitchen).
• Entertainment – Arrange controls for scenes in multiple areas. This strategy works for houses with both open-plan and traditional layouts.
• Lights Out – Turn lights out throughout the house (or leave a few on) from a keypad in the master bedroom. This is especially useful if the kitchen is on a different floor or if children tend to leave lights on in their bathrooms.
• Emergency –  Turn all lights on (or just strategically located ones) to provide light and an alert in case of emergency.
• External Connections -Turn lights on and off from a remote signal, such as your phone, computer, garage opener, audio-visual controller, or security system.

Applying Controls

Control over your lighting is your responsibility as the designer; do not delegate it to a contractor or even an engineer.

1. Start thinking about controls at the beginning of the design. Develop the controls plan based on the activities and users in the space and the lighting effects you are creating.
2. Assign a control for each layer of lighting. Divide layers into multiple channels if the lighting serves multiple areas in the space. Control different light sources on separate channels to ensure compatibility with the control equipment.
3. Decide whether you want manual or automatic input to the control and on/off or variable (dimmed) effects from the control.
4. Select controls, particularly dimmer, that are compatible with the type and magnitude of the load.
5. Decide if stand-alone controls will suffice or whether a system better meets your objectives.
6. For a system, identify the scenes, paths, or other strategies you want to create and select scene-control equipment accordingly.
7. Locate controls near entries and other convenient places. Use remotes to handle multiple locations.