How To Save Energy On Lighting

Intelligent lighting systemhours; by talking with custodial staff and security
Lighting any workplace costs money, yet businessespersonnel; and by reviewing the settings on lighting
lose profits every day by paying to operate lights intimers. You can also use a device called a datalogger,
unoccupied rooms. A better solution is to installwhich counts lighting hours and logs lighting times and
automatic lighting controls—called occupancydurations. A lighting professional can help you with this
sensors—that can switch lights on and off based onprocess.
occupancy, time of day, and the room's ambient lightWHY INSTALL OCCUPANCY SENSOR
level.CONTROLS?
Are occupancy sensors a smart solution for yourLighting occupancy sensors save energy and money
business? Read on to learn more about theseby detecting activity in work areas and automatically
energy-saving devices and how they may be able toturning lights on when people enter a room and off
help your business save energy and money.when people have left. Used properly, occupancy
WHY INSTALL OCCUPANCY SENSORsensors can be a cost-effective way to reduce the
CONTROLS?operating time of lighting systems, resulting in
Lighting occupancy sensors save energy and moneyoutstanding energy savings.
by detecting activity in work areas and automaticallyOne type of occupancy sensor is called a vacancy
turning lights on when people enter a room and offsensor. Vacancy sensors must be manually turned on
when people have left. Used properly, occupancyby an occupant entering a space, but will automatically
sensors can be a cost-effective way to reduce theturn the lights off if no activity is sensed after a set
operating time of lighting systems, resulting inperiod of time.
outstanding energy savings.Vacancy sensors work best in smaller enclosed areas
One type of occupancy sensor is called a vacancywhere occupants entering a room can easily access
sensor. Vacancy sensors must be manually turned onthe sensor.
by an occupant entering a space, but will automaticallyOccupancy sensors are most effective in spaces that
turn the lights off if no activity is sensed after a setare frequently unoccupied, including offices,
period of time.warehouses, storerooms, restrooms, loading docks,
Vacancy sensors work best in smaller enclosed areascorridors, stairwells, office lounges and conference
where occupants entering a room can easily accessrooms. Open-plan office spaces, where activity level
the sensor.may be high thoughout the workday, may not be good
Occupancy sensors are most effective in spaces thatcandidates for occupancy sensors that control the
are frequently unoccupied, including offices,general lighting, but may be a good place to consider
warehouses, storerooms, restrooms, loading docks,sensors that control plug-in office equipment and
corridors, stairwells, office lounges and conferencelighting at workstations.
rooms. Open-plan office spaces, where activity levelHOW OCCUPANCY SENSORS WORK
may be high thoughout the workday, may not be goodOccupancy sensors typically consist of a motion
candidates for occupancy sensors that control thedetector, electronic control, controllable switch (relay)
general lighting, but may be a good place to considerand power supply. Most units detect motion by sensing
sensors that control plug-in office equipment andheat (infrared radiation), shifts in the frequency of
lighting at workstations.reflected ultrasonic waves, or a combination of the
HOW OCCUPANCY SENSORS WORKtwo. When the sensor detects motion, the electronic
Occupancy sensors typically consist of a motioncontrol sends a signal to the relay, which opens or
detector, electronic control, controllable switch (relay)closes the power circuit, turning the lights on or off.
and power supply. Most units detect motion by sensing 
heat (infrared radiation), shifts in the frequency of 
reflected ultrasonic waves, or a combination of the 
two. When the sensor detects motion, the electronic 
control sends a signal to the relay, which opens or 
closes the power circuit, turning the lights on or off. 
 TYPES OF TECHNOLOGIES
  
  
 Passive Infrared (PIR) Occupancy Sensors Infrared
 sensors detect the difference in heat emitted by
 humans in motion from heat emitted by the
TYPES OF TECHNOLOGIESbackground space. While they are resistant to false
 triggering, they require a direct line of sight to sense
 motion.
Passive Infrared (PIR) Occupancy Sensors InfraredThe sensitivity of PIR sensors to small movements
sensors detect the difference in heat emitted bydecreases at distances greater than 15 feet. As a
humans in motion from heat emitted by theresult, these sensors are best suited for smaller,
background space. While they are resistant to falseenclosed spaces where the sensor has a view of the
triggering, they require a direct line of sight to senseactivity in the room and warehouse aisles. The
motion.sensor's field of view can be adjusted and should not
The sensitivity of PIR sensors to small movementsbe directed toward an open door where it may pick
decreases at distances greater than 15 feet. As aup people who are passing the doorway, but not
result, these sensors are best suited for smaller,entering the room. Ultrasonic Occupancy Sensors
enclosed spaces where the sensor has a view of theUltrasonic sensors emit a high-frequency signal that is
activity in the room and warehouse aisles. Theundetectable by humans and animals. This signal
sensor's field of view can be adjusted and should notbounces off objects, surfaces and people in a space. It
be directed toward an open door where it may pickthen returns to the sensor, which interprets change in
up people who are passing the doorway, but notthe frequency as motion.
entering the room. Ultrasonic Occupancy SensorsWhile these sensors do not require a line of sight and
Ultrasonic sensors emit a high-frequency signal that iscan sense movement around corners and objects,
undetectable by humans and animals. This signalthey may be prone to false triggering if placed too
bounces off objects, surfaces and people in a space. Itclose to an HVAC vent. Ultrasonic sensors are highly
then returns to the sensor, which interprets change insensitive to small movements up to 25 feet. They
the frequency as motion.typically offer a larger coverage area than
While these sensors do not require a line of sight andPIR sensors, but should not be mounted in high ceiling
can sense movement around corners and objects,applications (over 14 feet).
they may be prone to false triggering if placed too 
close to an HVAC vent. Ultrasonic sensors are highly 
sensitive to small movements up to 25 feet. TheyDual-Technology Sensors
typically offer a larger coverage area than 
PIR sensors, but should not be mounted in high ceilingDual-technology sensors employ both PIR and
applications (over 14 feet).ultrasonic technologies for maximum coverage and
 reliability with fewer false triggers. Because these
 sensors activate lights only when both technologies
Dual-Technology Sensorsdetect movement, and because either of the two
 technologies is enough to hold the lights on, these
Dual-technology sensors employ both PIR andsensors significantly reduce the possibility of false on
ultrasonic technologies for maximum coverage andand off triggers.
reliability with fewer false triggers. Because these 
sensors activate lights only when both technologies 
detect movement, and because either of the twoHigh-Bay Sensors
technologies is enough to hold the lights on, these 
sensors significantly reduce the possibility of false onOne of the most cost effective applications for
and off triggers.occupancy sensors is in warehouse aisles because
 these areas are not occupied on a constant basis. For
 warehouses with highintensity discharge (HID) light
High-Bay Sensorssources, lighting can be switched to a lower level, but it
 can't be turned completely off. HID light sources need
One of the most cost effective applications fortime to cool down and warm back up to full light
occupancy sensors is in warehouse aisles becauseoutput. This process takes too long and is not practical
these areas are not occupied on a constant basis. Forfor those who need to perform tasks in the space.
warehouses with highintensity discharge (HID) light"High/low" occupancy controls can switch lighting from
sources, lighting can be switched to a lower level, but itfull light output to approximately one-third light output
can't be turned completely off. HID light sources need(which uses about half the power) when the area is
time to cool down and warm back up to full lightunoccupied.
output. This process takes too long and is not practicalWhen the sensor detects activity, the light level and
for those who need to perform tasks in the space.power are restored to full almost immediately.
"High/low" occupancy controls can switch lighting fromFor even greater savings and instant on/off capability,
full light output to approximately one-third light outputconsider replacing HID fixtures with high-bay
(which uses about half the power) when the area isfluorescent fixtures. High-bay fluorescent fixtures use
unoccupied.much less energy than HID, and can be switched on
When the sensor detects activity, the light level andand off as occupancy and vacancy is detected in a
power are restored to full almost immediately.space. High-bay sensors can be individually fixture
For even greater savings and instant on/off capability,mounted, or a single sensor can control a full aisle of
consider replacing HID fixtures with high-baylight fixtures. Placement and delay settings are
fluorescent fixtures. High-bay fluorescent fixtures useimportant to prevent false triggering by detection of
much less energy than HID, and can be switched onactivity in the main walkway that does not move into
and off as occupancy and vacancy is detected in athe actual controlled aisle. Placement is also important
space. High-bay sensors can be individually fixtureto make sure that the sensor can "see" any activity
mounted, or a single sensor can control a full aisle ofanywhere in the aisle being controlled to prevent the
light fixtures. Placement and delay settings areoccupant from being left in the dark.
important to prevent false triggering by detection of 
activity in the main walkway that does not move into 
the actual controlled aisle. Placement is also importantWILL OCCUPANCY SENSORS WORK FOR YOU?
to make sure that the sensor can "see" any activity 
anywhere in the aisle being controlled to prevent theWhile occupancy sensors may reduce lighting by 50
occupant from being left in the dark.percent or more in some circumstances, the savings
 could be much smaller, so it's important to consider a
 wide range of issues before installing a sensor in a
WILL OCCUPANCY SENSORS WORK FOR YOU?particular location.
 To determine how much benefit you will gain in a given
While occupancy sensors may reduce lighting by 50application, monitor lighting use patterns and occupancy
percent or more in some circumstances, the savingspatterns simultaneously. From this, you can calculate
could be much smaller, so it's important to consider athe number of hours your business will save in lamp
wide range of issues before installing a sensor in aoperation, and then determine your energy savings.
particular location.You can establish lighting use patterns in a number of
To determine how much benefit you will gain in a givenways—by observing and recording when the lights in
application, monitor lighting use patterns and occupancydifferent parts of your facility are left on, including after
patterns simultaneously. From this, you can calculatehours; by talking with custodial staff and security
the number of hours your business will save in lamppersonnel; and by reviewing the settings on lighting
operation, and then determine your energy savings.timers. You can also use a device called a datalogger,
You can establish lighting use patterns in a number ofwhich counts lighting hours and logs lighting times and
ways—by observing and recording when the lights indurations. A lighting professional can help you with this
different parts of your facility are left on, including afterprocess.