Designing a HomeLighting Control System

In this chapter, you will learn about

• The types of loads to be controlled
• Lighting loads
• Lighting scenes
• Lighting zones
• Exterior lighting

Designing a whole house lighting system involves more than selecting the lighting for each individual room. Each room of a house can have several levels of lighting requirements. At different times a room’s occupants may desire a room to have ambient lighting or task lighting. The lighting system must be able to accommodate either lighting type easily. You must also consider how the lighting is to be provided and the type of light to be used.

In this chapter, you look at the various issues that must be considered when designing a lighting system for a room as well as an entire house.

Designing a Home Lighting System

Like the design process used for all systems in a home technology integration project, a systematic approach is necessary when designing a home lighting system. The use of a step-by-step approach ensures that the system is complete and addresses the needs and requirements of the homeowners.

The steps that should be used to design a home lighting system are as follows:

1. Identify the lighting loads to be controlled by each lighting control station.
2. Identify the lighting type associated with each load.
3. Calculate wattage requirements of each lighting circuit.
4. Determine the type of control devices to be used.
5. Determine the locations of the lighting controls and lay out their wiring loops.
6. Determine the lighting scenes to be programmed into each room or zone.
7. Plan and program the layout of the control switches.

Lighting Loads

As I discussed in Chapter 21, a lighting load is the amount of energy consumed to provide a certain level of illumination in a space. Knowing the lighting load of a house and its rooms and ensuring that the load doesn’t exceed the electrical power available to each space are essential parts of any lighting system design.

Types of Loads

On the electrical side of lighting, there are two types of loads that must be considered: inductive loads and resistive loads.

• Inductive loadAn inductive load is created by electrical devices that have moving parts, from devices with motors like power drills, fans, and vacuum cleaners to devices that include transformers, such as a fluorescent light fixture.
• Resistive loadA resistive load provides resistance to the flow of electrical current. Devices that create resistive loads include electric heaters, electric stoves, and even irons, but in the context of lighting loads, incandescent and halogen lamps create resistive loads.

The primary reason you should know the type of load a lighting device produces is that it allows you to match lighting controls to the type of load created by the fixture being controlled. Inductive load devices should not be controlled with resistive load controllers, and vice versa. Table 23-1 lists the common lighting types, their load type, and the type of controller typically matched to them.

Calculating Lighting Load

Prior to the pre-wire phase of a home’s construction, the lighting loads must be determined based on your understanding of the customer’s lighting requirements and desires.

The number of lighting fixtures on each of the lighting loads is used to determine the number of electrical circuits required to support the lighting requirements of a space.

Some estimate must be made as to the type and number of lighting fixtures to be used to accomplish the lighting requirements. Once this has been decided, it is possible to estimate the total lighting load for each circuit, room, and the entire house. For example, an incandescent load with three fixtures with 75-watt lamps each equals a total load of 225 watts. This information is needed when designing the control requirements and layout of the total lighting system.

The lighting loads are calculated slightly different from incandescent and fluorescent and HID lighting. Incandescent lighting loads are calculated as the wattage of all of the lamps connected to a single control, such as a switch, dimmer, or keypad.

When calculating the lighting load for a control connected to fluorescent or HID lamps, the power required by the ballasts may need to be factored in. Magnetic ballasts, whether for fluorescent or HID fixtures, use an additional 15 percent of power over and above the power requirements of the lamps, which means that the total wattage requirement for a lighting circuit needs to be multiplied by a factor of 1.15. However, if electronic ballasts are used, no additional wattage needs to be included.

Table 23-2 shows the lighting loads in a kitchen that has three incandescent fixtures of 100 watts each, two fluorescent fixtures with 40-watt lamps, and three under-counter fixtures with HID lamps of 60 watts each. Assume here that each lighting type is connected to a dedicated control.

Volt Amps, Watts, Lumens

The measurements used when designing a lighting system are volts, amperes, watts, and lumens. However, which of these measurements is used depends on what is being measured. These electrical and lighting measurements are discussed in the following sections.

Volt-Amps

Volt-amps, or voltage-amperes (VA), are commonly stated as kilo (1,000) volt-amps (KVA). VA represents the value of an AC circuit’s current (A) times its voltage (V). VA is just one way to define the electrical power requirements of a lighting fixture and its lamp. On resistive circuits, such as a circuit with incandescent lighting fixtures, the VA requirement can also be referred to as the apparent power requirement and stated as watts.

Watts

Watts are calculated using Ohm’s law, which computes watts as equal to the voltage times the amps on a circuit. All lamps use electricity to produce light and the amount of electricity required is stated in watts (W). One watt is the equivalent of 1 volt-amp. See Chapter 15 for more information about Ohm’s law.

Lighting lamps are all rated in watts, especially incandescent lamps. The wattage rating on a lamp indicates the amount of power the lamp uses to operate efficiently. On fluorescent fixtures, the lamps or tubes use electrical power, but because the fluorescent lights require a ballast to start up, its wattage (typically rated in amps) must be included in the power requirements of the fixture.

Lumens

Different lamps produce differing amounts of light. However, as the amount of light produced increases, so does the amount of power consumed to do so. For example, a 100-watt incandescent light bulb produces more light than a 60-watt bulb and requires 40 more watts of power to do so. Because of this, many people believe that the wattage rating on the bulb is a statement of how much light the bulb produces. To a certain extent this is comparatively true, but not exactly.

The amount of light produced by a lamp is measured in lumens. Lumens are typically stated as lumens per watt (LPW) on the packaging of a lamp. LPW indicates the number of lumens produced for each watt of power used and is, in effect, a measure of the lamp’s efficiency in converting power to light. Because some lamp types are more efficient than others, the LPW varies by lamp type. Incandescent lamps are generally rated in the 17–20 LPW range and fluorescent and high-output lamps can produce as much as 90 LPW.

Designing Room Lighting

Many countries around the world have standards for recommended levels of light for different types and uses of spaces. Of course there are a number of factors that must be considered when determining the level of light for any particular space. Rooms can require different light for a variety of activities. For example, a room that needs task lighting for detailed activities requires more light than a room that needs only ambient lighting. Other criteria for the amount of light a room requires are the preferences of the occupants and if the lighting levels are to be incorporated into a room’s dcor.

In new construction situations, the lighting designer may need to work closely with the architect to achieve a balance between the basic lighting requirements of an area and any artistic uses of lighting.

Fitting the Light to the Room

When designing the lighting levels for a space, you must consider the color of the light, the shape of a room and its contents, and the size and dimensions of the room.

Light Color

Light produced by lighting fixtures has color, which can be used to accent the dcor and design of a room and its contents. In a lighted room, the color on any surface is produced as a combination of the color of the surface and the color of the light hitting that surface.

The light produced by a lamp in a light fixture can literally change the perceived color of the walls and objects of a room. Color can also affect the mood of a room’s occupants. Bright and varied color in a room can create a mood of happiness, but monotone and dark colors and gloomy light can cause the opposite effect. Different room and lighting colors produce different effects—red is warm and blue or green is cold.

Objects in a Room

The angle at which light strikes an object can alter the perception of its size or shape by creating glares or shadows. Of course, this issue is difficult to predict for a home that may not be built or furnished yet, but if these issues are important to the homeowners, adjustable lighting should be considered.

Room Size and Dimensions

Light can be used to change the perception of a room’s size or volume, or to highlight a room’s design elements to make them more attention grabbing.

Different lighting levels and styles can be included in a room’s lighting plan to enhance a room’s features. For example, illuminating a ceiling can create the illusion of a high ceiling, and low lighting on a structural feature can make it appear smaller or closer. Lighting can also be used to create a virtual pathway through a room or between rooms. For example, when the rear of a pathway is more brightly lit than its entrance, visitors are drawn to the rear by the lighting.

Identifying Lighting Needs

Lighting is easily the least expensive decorating option available to homeowners, at least compared to the cost of remodeling and home decorating. This is a good reason for the lighting design to focus on complementing the lifestyle of the homeowners.

One very important consideration when identifying lighting needs and loads is the amount of sunlight available to light a room during the day. If a room doesn’t directly receive much sunlight, it may require day lighting as well as nighttime lighting.

Identify Room Lighting Needs

The lighting design for a room should take into account how a room is to be used, the mood or atmosphere desired, and any room dcor or contents that are to be highlighted. Another consideration is the color of the walls, ceiling, and floor coverings. Dark colors absorb light and light colors reflect light, and the lighting design should reflect this.

Rooms planned for multiple uses or activities may require multipurpose, adjustable, or perhaps multiple lighting types to provide the desired and recommended lighting for each activity. The recommendations for the common rooms of a house are as follows:

• BathroomThe lighting in a bathroom should be evenly distributed and as shadow-free as possible. Vanity lighting and recessed wall-mounted or ceiling-mounted fixtures are most commonly used in this space.
• BedroomsBedrooms typically require adjustable lighting along with task lighting. Ceiling-mounted or wall-mounted fixtures, controlled with a dimmer control, can be used for general lighting and task lighting supplied through table lamps or wall sconces can provide the task lighting.
• Dining roomDepending on the homeowners’ plans for how a dining room will be used, the lighting can include general, accent, and task lighting to provide the appropriate lighting levels for entertaining, family gatherings, and perhaps homework, hobbies, or games.
• Hallways and entrancesEntrances typically use a single, large ceiling-mounted lighting fixture, such as a chandelier, to provide general lighting. Hallways should be lighted every 8 to 10 feet for safety reasons, typically using recessed ceiling-mounted or wall-mounted sconces. Track lighting can also be used, especially if art or other objects are to be accent lighted.
• Living or family roomsThese rooms typically are multipurpose rooms. General lighting should be included for entertainment or watching TV; task lighting should be provided for reading and other close or detailed activities; and, if desired, accent lighting should be included to accent or highlight plants, art, or architectural features of the room.
• KitchenKitchens are work areas, but can also be gathering places. So, both general and task lighting is commonly installed in this area. Under-counter and ceiling-mounted task lighting is also commonly used in kitchen. If desired, cove or soffit luminaires can also be included to provide room accent lighting.

Lighting Scenes

A lighting scene is the preset combination of lighting levels for load(s) configured to provide the lighting appropriate for a particular activity or purpose. Lighting scenes can be manually adjusted using one or more dimmers or lighting controls. However, lighting scenes are typically associated with automatic controls and are one of the key benefits of lighting control.

Multiple lighting scenes can be defined for a single room or area. Different combinations of lighting level settings on the lighting fixtures in a room can be defined to create one or more ambient lighting levels, one or more task lighting patterns, and one or more accent lighting patterns. Selecting the desired lighting scene is then as easy as pressing a button on a keypad or a touch screen controller. For example, the keypad controller shown in Figure 23-1 has been programmed with four lighting selection.

Figure 23-1: A four-function keypad lighting control station

Photo courtesy of Smarthome, Inc.

Lighting Zones

A lighting zone can include one room, multiple rooms, open floor areas, hallways, stairways, exterior areas, and any combination of these areas. A lighting zone is an area of a house for which a lighting scene is established. When selected, a lighting scene illuminates a lighting zone. Likewise, a lighting zone can have many possible lighting scenes defined for it, but only one can be in use at a time.

When designing lighting scenes in lighting zones, the dimensions, shape, contents, and colors of the zone must be considered. If any part of a lighting zone prevents the desired lighting effect from being achieved, it may be necessary to divide the zone into multiple lighting zones.

Lighting Controls

There are essentially two types of lighting controls that can be installed in a home: dimming and switching. Each of these control types can achieve the goal of controlling the lighting level in a room, zone, or home, but they do it in slightly different ways.

Dimming Controls

Dimming controls changes the amount of light emitted by a lamp from none to the lamp’s full capability. Dimming controls are typically more expensive than switching controls, but they provide more cost saving and a less abrupt transition from one light level to another. Another advantage to a dimming controls is that they are more easily re-adjusted should the lighting requirements of a room, zone, or home change.

A variety of dimming control types is available, including rotary, slide, and touch controls. Manual rotary dimmers, like the one shown in Figure 23-2, are available for either incandescent or fluorescent lamps, although a fluorescent lamp also requires a dimmable ballast (more on this later in the chapter).

Figure 23-2: A rotary dimmer switch for controlling incandescent lamps

Switching Controls

A basic single-lamp switching control has two settings: the lamp is either on or off. More lamps, such as in a typical two-lamp fixture, can have both lamps on or both lamps off and there are no intermediate settings between on and off for any of the lamps.

Two-position light switches, like the one shown in Figure 23-3, are the most common lighting control used in a home.

Figure 23-3: A standard two-position switching control

Controlling Electrical Flow

One of the basic principles underlying a lighting control system is that what is actually being controlled is the electricity flowing to light fixtures. Dimming controls reduce or increase the amount of voltage flowing to a fixture, thereby decreasing or increasing the amount of light the fixture’s lamp produces. Switching controls either turn on or turn off the power flowing to the fixture, turning the lamp on or off.

Exterior Lighting

Lighting zones and lighting scenes aren’t just interior lighting areas. The exterior of a home and its landscaping, leisure areas, work spaces, and play areas can be designated as lighting zones in which safety, security, ambient, and accent lighting scenes can be defined.

The various types of exterior lighting scenes that can be created are as follows:

• Landscape lightingStandard and specialized lighting fixtures can be used to create a variety of lighting effects for a home’s exterior, especially with landscaping and gardens. Lighting can be used to create general moonlighting effects, focal points, uplights on trees, and spotlights on sculpture or other objects. The basic types of landscape lighting are
  • BacklightingThis type of lighting creates a backdrop of light that creates a visual depth in the dark.
  • DownlightingThis type of lighting effect is used to replace the sun and natural lighting on fixtures, walls, or gardens. The lighting fixtures can be mounted to walls, in taller trees, or mounted on elevated ground.
  • MoonlightingThis is a form of downlighting that uses lighting fixtures suspended in trees or mounted on higher objects to create a soft, diffused light that emulates the effects of moonlight.
  • UplightingThis type of lighting effect is used to produce large shadows and to illuminate a tree, statue, or other object. The typical placement for an uplighting fixture is on or near the ground.
  • Safety lightingA very important reason to include exterior lighting in a lighting design is safety. Safety lighting provides a lighted pathway on steps, sidewalks, walkways, and around potentially hazardous landscaping or objects. Safety lighting is down-pointing and positioned so that it is glare-free to avoid shining into anyone’s eyes.
  • Security lightingLighting spread evenly around buildings and their immediate surroundings, especially doorways and ground floor access points, can serve as a deterrent to prowlers or other intruders. Eliminating shadows is the primary objective of security lighting. Photocells and motion-detectors can add to the effectiveness of security lighting.

Review

A lighting load is the amount of energy consumed to provide a certain level of illumination in a space. The two types of loads that must be considered are inductive loads and resistive loads. Electrical devices with moving parts create an inductive load. A resistive load provides resistance to the flow of electrical current. Lighting load is determined by the amount of wattage used by the lamps connected to a single control. Volt-amps, or voltage-amperes (VA), measure the value of an AC circuit’s current (A) times its voltage (V). On resistive circuits, the VA requirement is the apparent power requirement and stated as watts. Watts are equal to the voltage times the amps on a circuit. The wattage rating of a lamp indicates the amount of power the lamp uses to operate efficiently. The light produced by a lamp is measured in lumens. Lumens per watt (LPW) indicate the number of lumens produced for each watt of power.

Light produced by lighting fixtures has color, which can be used to accent the dcor and design of a room and its contents. Color can also affect the mood of a room’s occupants. Light can be used to change the perception of a room’s size or volume, or to highlight a room’s decor.

Rooms planned for multiple uses or activities may require multipurpose, adjustable, or perhaps multiple lighting types to provide the desired and recommended lighting for each activity. Lighting scenes are preset combinations of lighting levels that provide lighting for a variety of activities. Lighting scenes are typically associated with automatic controls.

A lighting zone is an area where a lighting scene is established. If any part of a lighting zone prevents the desired lighting effect from being achieved, it may be necessary to divide the zone into multiple lighting zones.

The various types of exterior lighting scenes that can be created are landscape lighting, safety lighting, and security lighting. The basic types of landscape lighting are backlighting, downlighting, moonlighting, and uplighting.

Questions

1. The total wattage required by a lighting circuit controlled by a single control is the
   1. Lumens
   2. Lighting level
   3. Lighting load
   4. Power factor

2. A resistive load is defined as
   1. A load created by electrical devices with moving parts
   2. The type of load created by electric stoves and irons
   3. The load created by drills and vacuum cleaners
   4. The type of load created by a fluorescent fixture and its ballast

3. If a room’s lighting scheme includes three incandescent ceiling lights at 100 watts each on one control and five fluorescent lamps at 40 watts each in fixtures using electronic ballasts on a second control, what is the combined lighting load of these two circuits?
   1. 300 watts
   2. 400 watts
   3. 500 watts
   4. 575 watts

4. A watt is equivalent to a
   1. Foot candle
   2. Volt-amp
   3. Lumen
   4. KVA

5. Which of the following is not a design consideration for lighting scenes?
   1. Light color
   2. Color of the lighting fixture
   3. Room objects
   4. Room size

6. Which type of lighting is most appropriate for a bathroom?
   1. Sconce
   2. Chandelier
   3. Vanity
   4. Ambient

7. Which of the following best describes a lighting scene?
   1. A preset combination of lighting levels each designed for a certain activity
   2. The area covered by a preset lighting set
   3. One or more rooms for which lighting is defined
   4. Multiple lighting zones

8. Which of the following is not typically a type of exterior lighting?
   1. Backlighting
   2. Safety lighting
   3. Security lighting
   4. Ambient lighting

9. A programmed keypad controller is generally associated with what type of lighting control system?
   1. Single scene
   2. Single zone
   3. Automated/automatic
   4. Single room

10. The LPW rating for incandescent lighting is in the range of
    1. 1–4
    2. 17–20
    3. 60–100
    4. 1,000–1,500

Answers

1. C. Lumens measure the light produced by a lamp; lighting levels is a generic term not really specific to anything much; and power factors relate to the efficiency of lamps.
2. C. The other choices describe inductive loads.
3. C. The lighting load on the incandescent circuit is calculated as 3 times 100 for 300 watts and the lighting load on the fluorescent circuit is calculated as 5 times 40 for 200 watts. Because magnetic ballasts are not in use, no increase is made for the ballasts. So, the total is 500 watts.
4. B. Foot-candles measure the amount of light needed to illuminate a 1-foot square that is 1 foot from a light source and a lumen measures the intensity of that light. KVA refers to kilo-volt-amp.
5. B. The customer may have a preference, but it hardly matters to the lighting scene.
6. C. Another choice would be task lighting. None of the other choices are common in bathrooms.
7. A. Lighting scenes are used to preset certain lighting patterns, typically matched to certain activities, for a room.
8. D. Exterior lighting is rarely there to provide ambient lighting.
9. C. Manual systems, including single scene, zone, and room settings, use dimmers and slide controls.
10. B. LPW provides an indication to the brightness of a lamp.