Lighting Guide 1

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Lighting Guide 1

Introduction

This Green by Design buying guide provides information andsuggestions on the various aspects of green lighting systems to

help you make an educated choices about lighting. The

technology of green lighting systems has greatly improved

over traditional methods of both indoor and outdoor lighting.

This guide discusses the green aspects of artificial light,

natural light, light fixtures and lighting maintenance. All of

these components should be considered in order to effectively

increase the energy efficiency of lighting.

The tradition of incandescent lighting uses electricity to heat a thin filament until the heated

filament emits light. Unfortunately, the energy transfer in incandescent lighting is very

inefficient, so this method is now being replaced by more efficient lighting systems. Many

new systems contain ballasts, which are devices that limit the amount of current in the circuit.

To reduce the amount of electrical energy needed to produce an equivalent amount of

incandescent light, ballasts are included in the design of fluorescent lamps, compact

fluorescent lamps (CFL), high intensity discharge (HID) lamps, light-emitting diodes (LED)

and other forms of lighting.

As the demand for more energy efficient systems continues to increase,

many countries around the globe are attempting to ban the use ofinefficient, incandescent light. Consumers may readily identify green,

energy efficient lamps and light fixtures by looking for an ENERGY

STAR label on the product. ENERGY STAR is an internationally

recognized symbol, which specifies that products deliver the same or

better performance as comparable models while using less energy and saving money.

What Makes Lighting Green?

In lighting systems, greening represents methods to reduce or eliminate electrical

consumption, which in turn reduces emissions from fossil fuels and contaminants generated

by utility companies. Your purchase of energy efficient light bulbs, light fixtures and lightingsystems will reduce your energy costs and help the environment. There are several

components of lighting to consider when greening your lighting, as described below.

Light Source

The most effective greening techniques for lighting systems involve the use of natural light,

battery powered light, and solar powered light. These systems require no electrical power for

use. In fact, the only electrical energy consumption associated with these types of systems is

in their manufacture and installation.


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Technological advances are constantly evolving to further reduce energy use for both

industries and consumers. The chart below rates types of lighting according to their ability to

reduce or eliminate electrical consumption.

Types of Lighting by Ability to Reduce or Eliminate Electrical Power

TYPE OF

LIGHTINGEXAMPLES GREEN BENEFIT

Most

EfficientNatural Lighting WindowsSkylights Requires no power.

Battery Powered

LightingFlashlights Requires the batterys internal power.

Solar Powered

Lighting

Outdoor accent

lighting

Requires battery power to store

needed energy.

Least

EfficientElectrical Lighting

All other light

sourcesRequires electricalpower.

The most efficient types of lighting provide limited lighting not likely to meet the majority of

your lighting needs.

Light Needs

You need to consider how light will be used in a particular space. There are three primary

types of artificial lighting used for both indoor and outdoor lighting as shown below.

Three Main Types of Artificial Lighting

TYPE USE EXAMPLES

Ambient

lightingProvides general illumination.

Ceiling

fixtures.Security

lighting.

Task lighting Lighting to suit a particular task. Requires more thangeneral illumination. Under-the-counterlighting.Desk lamps.

Accent

lighting

Adds special features or enhances the aesthetic quality

of a lit environment.Garden lights.

Light Quantity

When choosing a lighting system, you need to understand how light is quantified. Terms used

to quantify lighting include watts, lux, lumens, and efficacy.

Watts
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Color temperature defines the color of a light source in the range of warm to cool. Yellow-red

colors, such as those in the flame of fire, are considered warm. In contrast, blue-green colors,

such as those in an overcast sky, are considered to be cool. Color temperatures are measured

in degrees Kelvin (oK) with temperatures in the range of 3,600 oK 5,500 oK considered cool

and temperatures in the range of 2,700 oK 3,000 oK considered warm. In contrast to

environmental temperatures, higher color temperatures represent cool and lower colortemperatures represent warm. Cool temperatures are closer to natural daylight while warm

temperatures are preferred for living spaces since they tend to be more flattering to skin tones

and clothing.

Color Retention

Color retention describes how colors appear when they are illuminated by a light source.

Since most objects are composed of multiple colors rather than a single color, some light

sources tend to change the color of objects. A Color Retention Index (CRI) is used to indicate

a light sources ability to render colors in the same fashion as sunlight. CRI is based on a scale

of 1 to 100 with 100 being the illumination produced by a 100-watt incandescent light bulb.Using energy efficient light bulbs, the CRI-100 index may be achieved using less electricity.

Glare

Glare is a measure of the excessive brightness from a direct light source on an object. Glare

makes it difficult to see an object and it results from the placement of an object relative to the

light source. Placing a light object in front of a dark background will cause glare. Bright

incandescent lamps are more likely to produce glare than large fluorescent lights.

Light Controls

Light controls are used to reduce the amount of time for which lights are turned on.

Dimmers

Dimmer control devices allow you to vary the level of lighting. Dimmers reduce energy costs

when used at low levels of dimming. Fluorescent dimmers are dedicated fixtures, which are

more energy efficient than traditional fluorescent light bulbs.

Photosensors

Photosensor controlled devices respond to ambient light to turn off during daylight hours andturn on at night. Some photosensor devices can be programmed to cut on at dusk and remain

on for only a predefined number of hours or minutes.

Occupancy Sensors

Occupancy controlled sensor devices are designed to detect activity, turn on when there is

activity and turn off when such activity ceases. There are two forms of occupancy sensors.

Ultrasonic sensors respond to sound and infrared sensors respond to heat and motion. Motion

sensors are a form of infrared occupancy sensors, designed to respond to motion only.

Timers


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Timers are control devices that may be set to turn on and off at predetermined times during a

24-hour period.

Light Maintenance

The energy efficiency of any lighting system is increased with proper maintenance since thelevel of light decreases with the aging and discoloration of lamps as well as dirt on the

fixtures, the lamps or the walls within a room. These conditions may reduce the total

illumination by as much as 50%. However, the light will continue to use the same amount of

energy. Some simple maintenance tips to preserve the efficacy of light are shown at in the

chart below.

Maintenance Tips for Lighting

Component Maintenance

Fixtures Remove dust every 6 to 24 months.

LampsRemove dust every 6 to 24 months.Never clean an incandescent light

while it is turned on as the bulb may shatter.

Lenses Remove dust every 6 to 24 months or whenever it appears yellow.

Walls within small

roomsClean or repaint every year.

Walls within large

rooms Clean or repaint every 2-3 years.

Product Comparison

The chart below includes specifications for incandescent, fluorescent, high-intensity discharge

and solid-state lamps.

Lighting Product Comparison 1

Lighting Type

Efficacy

(lumens/watt)

Lifetime

(hours) CRI2 Color Temp

(K)

Indoor /

Outdoor

Incandescent

Standard A bulb

10-17 750-2,50098-100

(excellent)

2,700-2,800

(warm)

I/O

Tungsten halogen

12-22 2,000-4,00098-100

(excellent)

2,900-3,200

(warm toneutral)

I/O
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Reflector

12-19 2,000-3,00098-100

(excellent)

2,800

(warm)

I/O

Fluorescent

Straight tube

30-1107,000-

24,000

50-90

(fair to good)

2,700-6,500

(warm to

cold)

I/O

Compact fluorescent

lamp (CFL)50-70 10,000

65-88

(good)

2,700-6,500

(warm to

cold)

I/O

Circline 40-50 12,000 I

High-Intensity Discharge

Mercury vapor

25-6016,000-

24,000

50

(poor to fair)

3,200-7,000

(warm to

cold)

O

Metal halide70-115

5,000-20,000

70

(fair)

3,700

(cold)

I/O

High-pressure

sodium 50-14016,000-

24,000

25

(poor)

2,100

(warm)

O

Low-Pressure

Sodium 60-15012,000-

18,000

-44

(very poor)

O

Solid State

Cool white LED47-64

35,000-

50,000>5,000 I/O

Warm white LED25-44

35,000-

50,00080 2,600-5,000 I/O

Incandescent lamps are the most inefficient of lamp types even though they provide

excellent color retention. They are the least expensive to purchase, but they are the most

expensive to operate. Incandescent lamps also provide the shortest average life.


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Long-life incandescent light bulbs are a variation of standard A bulbs, which have a thicker

filament. They offer a longer life, but long-life bulbs are even less energy efficient than

standard bulbs.

Tungsten halogen lamps also include a filament, as do all incandescent lamps, but they are

more energy efficient than standard A bulbs. Tungsten halogen lamps include a gas fillingwith an inner coating to reflect and recycle heat to keep the filament hot, thereby reducing the

consumption of electrical energy. They are more expensive to purchase than standard A

bulbs, but less expensive to operate. Tungsten halogen lamps are typically used for accent

lighting.

Reflector lamps (type R) include floodlights and spot lights, which direct and distribute light

to a specific area. There are two types of reflector lamps. Parabolic aluminized lamps (type

PAR) are used for outdoor lighting. Ellipsoidal lamps (type ER) focus and project light

approximately two inches to the front of its enclosure. They are typically used to project light

downward from recessed light fixtures. Type ER reflector lamps are twice as efficient as type

PAR lamps in recessed lighting fixtures

Fluorescent lampsprovide the same amount of illumination as incandescent lamps while

using 25% to 35% of the energy required for incandescent lamps. They also last 10 times

longer.

Straight tube lampsproduce an electric current, conducted through the mercury and inert

gases inside of the fluorescent tube. This allows the phosphor coating located on the glass to

emit light.

Ballasts are used to generate a high start-up voltage and then regulate the operating current.

Electronic ballasts have replaced the electromagnetic ballasts used in traditional fluorescent

lamps. Electronic ballasts operate at high frequencies and eliminate the flicker and noise that

was inherent in traditional fluorescent lamps.

CFL lamps operate in a similar manner as straight tube lamps except that some CFLs have

dedicated ballasts, which allow CFLs to be used as replacements for traditional incandescent

lamps. The following chart shows the approximate wattage of an incandescent lamp versus an

ENERGY STAR qualified CFL lamp.

Incandescent vs. CFL lamps

Min Light Standard lamp CFL lamp

lumens (l) watts (w) (l/w) watts (w) (l/w)

450 40 11.25 9-13 .02-.029

800 60 13.33 13-15 .001-.019

1,100 75 14.67 18-25 .016-.023

1,600 100 16.00 23-30 .014-.019


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2,600 150 17.33 30-52 .012-.02

HID lamps provide the same amount of illumination as incandescent lamps while saving

75% to 90% of the energy required for incandescent lamps. HID lamps offer the highest

efficacy and life of any type of light. Intense light is produced from an enclosed electric arc.

HID lamps require ballasts, which take some time to establish the electric arc. This may createas much as a ten-minute delay between turning the light on and the actual production of light.

Mercury vapor lamps were traditionally used for street lighting, arenas and gymnasiums.

Metal Halide lamps areused to replace most mercury vapor lamps that were traditionally

used in arenas and gymnasiums since they offer better color rendering and higher energy

efficiency. Even greater energy savings may be realized by replacing mercury vapor lamps

with high-pressure sodium lamps.

High-pressure sodium lamps provide poorer color rendition than metal halide lamps, but

they offer a longer life. This type of lighting has become the preferred choice for outdoorlighting.

Low-pressure sodium lamps are more energy efficient than high-pressure sodium lamps, but

they offer poor color rendition. This type of lighting is typically used where color is not

essential, such as on highways and as security lighting.

Solid-state lamps are the newest and fastest growing technological innovation used in

lighting. Data to characterize lights in this category are scarce and continuously evolving.

LED lamps are solid-state lamps that illuminate and direct light, dependent upon the shape

and composition of the lenses and the package structure.

What To Look For

If your home has windows that face north and south, you can expect to achieve more benefit

from daylight than if your home has windows that face east and west. Windows that face

south allow the most winter daylight to enter and they allow little direct sunlight to enter in

the summer. Windows that face north allow relatively even amounts of daylight to enter with

little glare and very little direct sunlight in the summer. Windows that face east allow sunlight

in the morning while windows that face west allow sunlight in the evenings. However, the

sunlight may cause glare, allow for excessive heat in the summer and contribute very little tosolar heating systems during the winter.

Choose fluorescent lamps for high-demand ceiling and wall lighting that typically remains on

for two or more hours.

Choose light wall colors to reduce the need for artificial light.

Carefully inspect light bulb packaging for its ratings of lumens, watts and life. The higher the

number of lumens, the more light it provides. The lower the number of watts, the more you

will save in utility costs. The higher the life, the less often you have to replace the lamp.

Choose the number of lumens to suit your needs and then seek a lamp with the least amountof watts to achieve that number of lumens.


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HID lamps take time to generate light and are most suitable for situations where a light is used

for hours at a time. They are not suitable for use with motion sensors.

Summary

Look for light bulbs and fixtures that indicate ENERGY STAR compliance. Also seeklighting fixtures that are approved by the Underwriters

Laboratory (UL). The UL symbol specifes that fixtures are

airtight, insulation contact (IC) rated, and meet safety

standards.

Sources

http://apps1.eere.energy.gov/consumer/

http://oee.nrcan.gc.ca/energystar/english/pdf/basic-facts-residential-e.pdf

http://www.brillianz.co.uk/data/documents/Lumen.pdf

http://www.energystar.gov/index.cfm?c=about.ab_index

1 Specifications per the U.S. Department of Energy Consumer Guide to Energy Efficiency

and Renewable Energy

2 CRI is Color Retention Index
http://apps1.eere.energy.gov/buildings/publications/pdfs/building_america/26467.pdfhttp://oee.nrcan.gc.ca/energystar/english/pdf/basic-facts-residential-e.pdfhttp://www.brillianz.co.uk/data/documents/Lumen.pdfhttp://www.energystar.gov/index.cfm?c=about.ab_indexhttp://tositek.com/wp-admin/#sdfootnote1anchttp://tositek.com/wp-admin/#sdfootnote2anchttp://apps1.eere.energy.gov/buildings/publications/pdfs/building_america/26467.pdfhttp://oee.nrcan.gc.ca/energystar/english/pdf/basic-facts-residential-e.pdfhttp://www.brillianz.co.uk/data/documents/Lumen.pdfhttp://www.energystar.gov/index.cfm?c=about.ab_indexhttp://tositek.com/wp-admin/#sdfootnote1anchttp://tositek.com/wp-admin/#sdfootnote2anc

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Lighting Guide 1