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Occupancy and Vacancy Sensors: The Definitive Guide

Horace He     |     Oct 27, 2021     |     14 min read

Occupancy and vacancy sensors are typically one kind of motion sensor detectors that can automatically control your lighting save energy and bring convenience. They are one of the most important and widely used lighting control systems in homes and commercial buildings.

This comprehensive guide includes everything you need to know more about occupancy sensors to help you choose the best sensor for your residential and commercial applications.

What is an Occupancy Sensor?

An occupancy sensor is a kind of motion sensor that will automatically turn on the lights when detecting the presence of a person and automatically turn off the lights when no presence is detected to save energy and provide convenience. They are primarily used as light switches, but they can also be used to control fans, HVAC, or other electronic devices to achieve the auto-on and auto-off features.

An occupancy sensor looks like a light switch with a lens for motion detection.

An occupancy sensor looks like a light switch with a lens for motion detection.

Occupancy sensors are commonly referred to as Auto-ON, Auto-OFF sensors. Some sensors can be set only to turn ON/OFF a partial of lights to achieve dimming lighting, and these sensors are called partial-ON, partial-OFF sensors by some people.

occupancy sensor working mode

Occupancy mode motion sensor

Generally, an occupancy sensor includes features like:

  • Automatically turn on the light and turn off the light.
  • Adjust sensitivity level from low to high.
  • Adjust light sensor level.
  • Adjust time delay from 10 seconds up to 20~30 minutes.
  • A manual override feature to turn off the light regardless of motion detection.
  • A 15~30 second vacancy confirmation time after the time delay, to turn the lights back on after the time delay has expired to prevent false-OFFs.
  • A visible signal that indicates the occupancy sensor is operating correctly and detecting motions. (optional)
  • A manual override feature to keep the light always on or off like a regular switch. (optional)

What is a Vacancy Sensor?

A vacancy sensor is similar to an occupancy sensor, but it requires people to turn on the light manually like a mechanical light switch, and then the vacancy sensor will automatically turn off the light after some time duration when the room is empty. 

vacancy sensor working mode

Vacancy mode motion sensor

Vacancy sensors are commonly referred to as Manual-ON, Auto-OFF sensors due to their unique features.

Compared to occupancy sensors, vacancy sensors can save significant more energy as the light must be turned on manually, so the light will remain off for the majority of the day and there are no false-ONs triggered by unwanted motions like occupancy sensors.

Generally, a vacancy sensor includes features like:

  • Manually turn on the light and automatically turn off the light.
  • Adjust sensitivity level from low to high.
  • Adjust light sensor level.
  • Adjust time delay up from 10 seconds to 20~30 minutes.
  • A manual override feature to turn off the light regardless of motion detection.
  • A 15~30 second vacancy confirmation time after the time delay, to turn the lights back on after the time delay has expired to prevent false-OFFs.
  • A visible signal that indicates the occupancy sensor is operating correctly and detecting motions. (optional)
  • A manual override feature to keep the light always on or off like a regular switch. (optional)

What is an Occupancy/Vacancy Sensor?

Most occupancy sensors have a built-in vacancy mode to provide more flexibility for users, so they are labeled as occupancy/vacancy sensors. Users can freely switch from occupancy to vacancy mode or vice versa to meet the actual requirement.

a typical occupancy sensor allow user to switch from occupancy mode to vacancy mode

The blue button is to switch between vacancy mode and occupancy mode

Well, most occupancy sensors on markets have vacancy mode combined, so people would use occupancy sensors to refer to occupancy-only and occupancy/vacancy sensors. But the term vacancy sensor is usually referred to as vacancy-only sensors.

In this article, we may use occupancy sensors to refer to both occupancy-only and occupancy/vacancy all in one sensor.

How do Occupancy Sensors Work?

Occupancy sensors rely on different technology for detecting motion and the presence of people to determine whether the room is occupied or not. Currently, there are mainly use two technologies that occupancy sensors use: PIR and ultrasonic. And there are also sensors that use both technologies for the best result, often referred to as dual-technology or dual-tech sensors.

PIR Sensors

Passive infrared(PIR) occupancy sensors, or IR sensors, passive infrared detectors, use a multi-faceted lens to detect motion or presence of a person by measuring the infrared. The word passive means that the sensor does not radiate energy for detection but to passively detect the infrared radiation emitted by or reflected from moving objects or people.

rz021 us occupancy vacancy sensor switch front

A typical PIR sensor switch: The lens above the button is to detect infrared signals.

Detection Range and Coverage

Due to how PIR sensors work, the PIR motion sensors are more sensitive to lateral, major movement such as people walking, up to about 40 feet(12 m) but have limited sensitivity to minor movement, like typing, at a distance greater than 15 feet(4.5 m).

What’s more, to successfully detect the emitted infrared from moving objects, PIR sensors require a clear line of sight because they can not see through obstacles, glasses, or corners to detect infrared signals.

PIR occupancy motion sensor cannot detect motion through glass

The detection range can be adjusted by masking part of the lens to force the PIR sensor to detect only a selective range, so they are not able to detect motion from noise sources such as walking and people passing from outside the room to reduce false-ONs.

False-ONs and false-OFFs are lighting triggered by unwanted signals. False-ON means the lights are turned on when the room is empty, and false-OFF means the lights shut down even when there are still people in the room.

PIR Sensor is Good for:

PIR sensors are most suitable for medium to small enclosed spaces where the sensor can have a clear line of sight for major motion detections without obstacles blocking the sight. 

PIR sensors are very consistent, durable and they consume very low energy. They are the ideal lighting control solution for long-term commercial applications. They are also suitable for outdoor areas like aisles, as the PIR sensors only passively detect infrared emitted by people, whereas ultrasonic sensors are not good in telling whether the sound is from people or moving cars.

enclosed space

PIR occupancy sensors are great for enclosed commercial spaces

PIR sensors are also suitable for spaces with high airflow, where ultrasonic sensors are not competent in such applications. The high airflow is a distraction noise for ultrasonic motion detection, but it is not a noise source for PIR sensors.

When you want to monitor and detect motion in a selective area of space, PIR sensor is the way to go. By masking part of the lens on the sensor with removable adhesive strips to lower and restrict its detection coverage, you can adjust the area that the sensor can detect to not let the sensor detect motion from unwanted areas, such as detecting motion from outside your office room.

Best applications for PIR sensors include:

Private offices, classrooms, copy rooms, restrooms, storage areas, conference rooms, warehouses, break rooms, corridors, filing areas, and other spaces, lobbies, hallways, and outdoor spaces

PIR Sensor is Not Good for:

On the contrary, PIR sensors are not good for places with obstacles blocking the sensor so that it cannot have a clear sight of view to detect motion. Also, they are not quite accurate in detecting low and small motions.

Additionally, PIR sensors cannot be installed near distraction sources where heat changes rapidly, such as HVAC and coffee machines.

Ultrasonic Sensor

Ultrasonic sensors emit high-frequency sound wave signals throughout an area to monitor and detect the reflected signal for changes. If there is a continuous change in the reflected frequency, then ultrasonic sensors assume there is motion detected, meaning the space is occupied. If the reflected pattern stays the same then the sensors assume there is no motion, the space is vacant and not occupied.

ultrasonic ceiling sensor

A ceiling mount ultrasonic sensor

Detection Range and Coverage

Ultrasonic sensors do not require a direct line of sight like PIR sensors, so they can detect motions around corners and obstacles, making them the ideal solution for applications with multiple stalls and obstacles such as public restrooms and open offices.

public restroom with stall

Ultrasonic occupancy sensors can detect motion regardless of obstacles like public restroom with stalls

Ultrasonic sensors are also highly sensitive to low motion activity and minor movements like typing and turning pages at a distance of up to 25 feet. They are most sensitive to motions to and from the sensor due to the characteristics of ultrasonics.

Ultrasonic sensors typically have a larger coverage area than PIR sensors. But the sensor’s view(detection range) cannot be adjusted like PIR sensors by simply covering part of the lens.

Ultrasonic Sensor is Good for:

Ultrasonic sensors are most suitable for open spaces and spaces with obstacles where PIR sensors are not good for. As ultrasonic sensors are more sensitive to fine motions, they are great for applications where a high level of sensitivity is required, such as open offices, restrooms, and enclosed stairways.

student typing with minor motion

Ultrasonic occupancy sensors can detect minor motions like typing or turning pages.

Best applications for Ultrasonic sensors include:

Open spaces, open offices, spaces with obstacles, spaces with hard surfaces, restrooms, enclosed hallways and stairways.

Ultrasonic Sensor is Not Good for:

Ultrasonic sensors are not good for places with high levels of airflow vibrations because the vibration can trick the sensors to falsely turn on and off. 

They are not competent for applications that require only to detect a selective range, such as control of individual warehouse aisles.

Dual-Techonolgy Sensor

Dual-tech occupancy sensors combine PIR and ultrasonic technologies to increase the sensor’s reliability and flexibility for complex and high-sensitivity applications. In order to turn the light on, the motion should be detected by both PIR and ultrasonic technology at the same time. And the light will stay on if either technology is continuously detecting motion to prevent false-offs.

a dual-tech sensor with pir and ultrasonic sensor combined

A dual-tech sensor combines both lens and ultrasonic detectors.

This combination of technologies can significantly reduce the possibilities of false-ONs and false-OFFs.

Most dual-technology sensors are also self-adaptive to adjust sensitivity and timing automatically. 

classroom

Classroom is a large space with many obstacles

Dual-Tech Sensor is Good for:

Dual-Technology sensors are most suitable for large spaces with limited sight of view, like open offices, libraries, common areas, classrooms, conference rooms, and spaces where a higher degree of detection is requested.

Dual-Tech Sensor is Not Good for:

Dual-tech sensors, like most high-tech electronic products, their price is relatively high, so they are not suitable for applications where the budget is too limited and sensitive.

Occupancy Sensor Types

Occupancy sensors can be grouped and sorted by different factors, such as sensor technology, install locations, working voltage, etc. To help users choose the most suitable sensor types for their home and commercial application, we will try to cover every major occupancy sensor type and explain their advantages, differences, and usages.

Wall Mount Occupancy Sensor

Wall mount occupancy sensors, or wall mount motion sensors, are one of the most seen and used sensor switches. Wall mount occupancy sensors are famous for their easy installation, and they are designed to fit into regular wall boxes to replace regular light switches without an effort. As most wall mount sensors are installed in the wall box, they are also called in-wall sensor switches.

rz023 uk style motion sensor on wall

An in-wall motion sensor light switch

Again, as wall mount motion sensors usually come with a built-in light switch, so you would see people prefer to call them a wall mount motion switch, wall mount motion light switch or motion sensor light switch. They are more like a light switch with a motion detection feature rather than a motion sensor with a switch.

Another advantage of wall mount sensor switch is that people can manually control the sensor as a light switch compared to controlling ceiling mount sensors. For a ceiling mount occupancy sensor, you need to connect one additional switch to override or control the light. But for wall mount sensors, the light switch and sensor are already built-in into one, so users would only need a single wall motion sensor switch for motion detection and light switch control.

private office

Wall mount occupancy sensor can have a clear sight of view in private offices

When using wall mount sensors, you need to be careful where you install the sensors. You should find proper locations for the sensor to detect people’s presence correctly and not detect unwanted motions. 

For example, when you mount a wall occupancy sensor, you should install the sensor to the wall with the door so the sensors cannot detect motions from outside the room. If the sensors can detect people passing by from outside the room and falsely turn on the light, it’s would be electricity waste and can be avoided. 

What’s more, wall mount motion sensors’ detection area can also be blocked or affected by multiple barriers or walls in the room, so finding a good location for clear sight is essential.

Another thing to notice about wall mount sensors is the wiring.

For the occupancy sensor to control the lights, the sensor needs its own power supply to work individually because the sensor would always need its own electricity to detect motion even when the light switch is turned off.

Usually, there are four wires in a wall box, there are two load wires, one ground wire and one neutral wire. So here comes the difference.

Neutral Wire Required Sensor

As stated above, for the occupancy sensor to work independently to control the light, most occupancy sensors will require a neutral wire to work. These types of occupancy sensors are often labeled “neutral required” or “neutral wire required” occupancy sensors. 

wiring and backend of a four wire wall sensor switch, neutral wire required

Green and Red load wire, Black ground wire and White neutral wire

So with neutral wire required occupancy sensors, there are two load wires, one neutral wire and one ground wire. You would need the same four wires in your wall box for proper wiring.

If you cannot find the four wires in your wall box, you might ground wire type for the sensor to work. 

Ground Wire Required Sensor

For older built houses that do not have a neutral wire in their wall box, you would need a ground wire required type occupancy sensor switch. 

These types of ground wire required occupancy sensors would use the ground wire to complete the circuit for the occupancy sensor to work independently. 

wiring and backend of a three wire wall sensor switch, ground wire required

Green and Red load wire and Black ground wire

So with ground wire required type of occupancy sensors, there are two load wires and one ground wire. You would need the same wires in your wall box to correctly install and wire the switch and your lights.

Wall Box / Junction Box

As we’ve mentioned above, wall mount sensor switches are usually designed to fit into wall boxes or gang box(terms used in the US region), so users should pay attention to the sensors’ wall box size to make sure they fit your wallbox.

In the US, the wall box is size is 2” wide x 3.0” high. They are commonly called 1-gang, single gang or one gang wall box.

standard U.S. 1 gang wall box

U.S. standard single gang wall box

In the EU standard countries, the wall box size is 86mm (W) x 86mm (H) (3.425” x 3.425”). They are commonly called 86 boxes.

UK and EU, 86 junction box

EU, UK standard 86 wall box

Ceiling Mount Occupancy Sensor

Ceiling mount occupancy sensors are another major type of occupancy sensor. They are mounted on the ceiling to provide a broad detection coverage with a 360-degree point of view. Multiple ceiling sensors can also be networked to offer extensive coverage. Ceiling mounted sensors are appropriate for large area motion detection with obstacles where wall mount sensors are not competent.

ceiling occupancy sensor installed next to the light

Ceiling occupancy sensor Installed next to the light

Unlike wall mount motion sensors, ceiling mount occupancy sensors do not come with a switch as people cannot operate the sensor installed high in the ceiling. 

open office

In open offices with no walls, ceiling mount occupancy sensors can detect motions

Ceiling occupancy sensors are simply motion sensors. If you need to override or manually control the lights, you need an additional light switch on the wall connected to the ceiling sensor.

As they do not allow manual light switching, ceiling mount occupancy sensors are better for communal spaces, such as lobbies and shared public bathrooms, because ceiling occupancy sensors work fully independently and automatically.

For the same reason, as ceiling mount sensors are fully automatic and they work solely as motion detectors only, so you would see people often call them ceiling mount occupancy sensors or ceiling motion sensors.

When using ceiling occupancy sensors, though they can have a large view on the ceiling, you still need to pay attention to avoid the sensor being blocked. Such as in places like classrooms, the hanging things on the ceiling can obstruct the sensor’s views and detection coverage.

Similar to wall sensors, when installing the ceiling occupancy sensors, try to avoid having the sensor look out the given space’s door. Keep ceiling-mounted sensors close to the wall with the door on it to let it focus on detecting motion only in the room.

High Bay Occupancy Sensor

High bay occupancy sensors are specially designed for high ceilings where normal ceiling mount occupancy sensors cannot cover. High bay occupancy sensors can usually support a height from 20 feet to 45 feet.

a high bay occupancy sensor

High bay occupancy sensor looks different ceiling sensor

Line Voltage Sensor

Line voltage sensors are occupancy sensors that work on 120V to 277V line voltage. Most lighting systems run off of line voltage, so do occupancy sensors.

Most line voltage occupancy sensors are compatible with a voltage from 110V to 277V to cover the 110V residential voltage, 277V commercial voltage in the US, and the standard 220V voltage in other countries like the UK and the EU for lighting.

Additionally, when choosing line voltage occupancy sensors, there are 120V voltage sensors mainly used for residential usage and sensors that accept 120~277V voltage range that are adaptive for residential and commercial applications. If you want to install sensors on commercial applications or facilities, pay attention to the voltage specification before buying.

Low Voltage Sensor

Low voltage sensors work on low voltage power packs, usually 24V. As you can freely move and locate the power packs compared to fixed line voltage sensors, low voltage occupancy sensors are mostly seen and used on ceilings where regular ceiling sensors have difficulties in installation and getting electricity.

power pack for low voltage and wireless sensor

Low voltage occupancy sensor requires a power pack for electricity

Low Current Rating Sensor

Most occupancy sensors are designed to control lighting fixtures with a small current rating up to 2A~5A.

High Current Rating Sensor

If you want to use the occupancy sensors to control fans, HVAC or multiple lighting fixtures automatically, you might need a higher current rating from 5A to 10A for the high load.

exhaust fan

To connect occupancy sensor to exhaust fans, you need high current rating occupancy sensors to load the fan.

Single-Pole Sensor Switch

A single-pole sensor switch is the standard switch to control a light fixture from a single location. A single-pole switch is always marked on and off on the toggle. 

Most occupancy sensors are single pole sensor switches that can control the lighting in a single location. Single pole occupancy sensor switches are competent for most indoor applications like bedrooms, private offices, meeting rooms. 

Three-Way Sensor Switch

Three-way sensor switches are used in pairs to allow you to control a light from two different locations. Three-way switches have no ON/OFF markings because the on and off positions will vary as the switches are used. 

long hall way that need three way occupancy sensors

Install three-way occupancy sensors in both ends of the long hallway

If you want to control the light in two locations, such as the beginning and end of a long hallway, a three-way occupancy sensor is what you need. You need to install and connect the three-way occupancy sensor in both ends of the hallway to allow occupancy sensors to turn on and off the light no matter from each side you enter or leave.

Wired Sensors

Wired sensors, as its name says, are sensors that are connected by wires. They are the most common type of sensors.  

Wireless Sensors

Wireless sensors are growing in popularity, especially for upgrading existing lighting controls. They are easy and quick to install without the worry of messing with existing wires or adding new wires. 

Wireless occupancy sensors are powered by an internal battery and send motion singles wirelessly to the controller to turn ON/OFF the light.

Single Mode Sensor

A single mode sensor are either an occupancy sensor or a vacancy sensor. These sensors are suitable for applications that have a strong purpose or requirement of how the sensors will be used to control the lights. 

For most commercial applications, you don’t need to change the mode from occupancy to vacancy or vice versa after the sensor is properly installed. 

For example, the vacancy sensor is appropriate for the meeting room as the meeting room is rarely used. An occupancy sensor can cause false-ONs when people are passing by the room which can be avoided.

All-In-One Occupancy and Vacancy Sensor

Nowadays, many suppliers offer 2-in-1 or 3-in-1 occupancy/vacancy motion sensors that allow you to freely switch from occupancy mode to vacancy mode for maximum flexibility. These types of all-in-one occupancy and vacancy sensors are favored by more and more people, especially homeowners. 

In most commercial places, one single occupancy or vacancy sensor is usually sufficient. People rely on their automatic lighting control for energy-saving, as the daily routine in business areas is fixed, you don’t have to change from occupancy to vacancy mode too often.

all in one occupancy sensor function description

With all-in-one occupancy and vacancy sensors you can switch mode any time you need

False-Ons and False-OFFs in commercial places would not be that annoying as we care about our business and work. But in residential applications, single occupancy or vacancy sensor could cause trouble. In our cozy homes, any minor mistakes may ruin our mood when enjoying our sweet home life.

All-in-one occupancy sensors are the ideal solution for homeowners. For example, most homeowners are not quite sure whether to use occupancy or vacancy sensors until tried and tested. For all-in-one sensors, you don’t have to remove the sensor and install a new one, you can just change the mode on the sensors.

What’s more, we may need to change the sensor mode occasionally for a better experience. We may need occupancy sensor mode in one room for a short period of time and change it back to vacancy mode. All-in-one sensors are much flexible for homeowners to adjust for the best result.

Occupancy Sensor Features and Functions

There are some standard features that most occupancy sensors would include.

Time Delay Adjustment

Time delay allows users to control the amount of time before the light turns off after the sensors detect vacancy. The shorter the time delay is, the more energy the sensor can save. Longer time-delay can offer more assurance that the light will not turn off while there is still little activity in the room. 

Normally, occupancy sensors have several time-delay options by default, from 15s, 1min, 3min, 5min, 15min to 30min to offer flexibility for versatile applications. While a lower time delay offers more energy savings, it might cause occupant dissatisfaction if the lights prematurely turn off. A longer time delay offers more assurance that the light will not turn off if there is little activity in the room. Generally, a 15-minute delay is recommended to achieve the most efficient balance of lamp life and energy efficiency. 

ceiling occupancy sensor function description

Change time delay on a ceiling mount occupancy sensor

The energy code used to require a maximum of 30 minutes time delay but now they reduce it to 20 minutes for a higher energy-saving efficiency.

Many suppliers will add a 30 seconds vacancy confirmation window time after the time delay. So even if the time delay expires that the light turns off, uses can still activate the light again, such as waving hands or slightly moving your body within the 30s window time to prevent such false-OFFs.

Light Sensor

To further increase energy savings, an ambient light sensor is usually included in occupancy sensors to assure the light will not turn on when there is ample natural light. 

There are usually a variety of pre-set light values from 15 Lux to 35 Lux for adjustment. E.g., if you set the light sensor to 15 Lux(One foot-candle is 10 Lux), the sensor would only turn on the light when the ambient light is under 15Lux. 

with ample ambinet light

If there is ample ambient light, then the occupancy sensor will not turn on the light

This feature can save more energy in daylight when there is adequate natural light. Natural light is also beneficial for people’s health.

Sensor Sensitivity

Sensitivity is the sensor’s ability to detect motion at a distance. Most sensors can be adjusted to low or high sensitivity for specific applications.

If the occupancy sensor is not being able to detect desired motions, you may set the sensitivity to high. If the sensor is frequently triggered by distraction sources that you don’t want with false-ONs, you can set the sensitivity to low.

Why Use an Occupancy Sensor?

There are plenty of good reasons to use an occupancy sensor than a manual light switch. We’ll talk about some good reasons here.

Save Energy And Electric Bills

Using occupancy and vacancy sensors is a key strategy for saving lighting energy. On average, occupancy and vacancy sensors can save 30% to 60% lighting energy in residential and commercial applications, some even up to 80% energy saving.

According to the US Department of Energy, today’s commercial building consumes 19% of the US energy and lighting accounts for 38% of the electricity usage.

According to the US Environmental Protection Agency, By using automatic shutoff, scheduled shutoff such as occupancy sensors, energy savings can range from 40% to 46% in classrooms, 13% to 50% in private offices, 30% to 90% in restrooms, 22% to 65% in conference rooms, 30% to 80% in corridors, and 45% to 80% in storage areas. 

47% of people in the US believe the biggest waste of electricity is the lights left on in an empty room, according to Lutron.

According to the Lawrence Berkeley National Laboratory, occupancy-based strategies can produce average lighting energy savings of 24%.

To save energy is to save your electricity bills, obviously.

Staying Up to Energy Code

In plain words, you have to use occupancy or vacancy sensors because energy codes require you to do so in commercial buildings.

Most energy codes would require an occupancy or vacancy sensor system in commercial buildings. Whether it’s general code like ASHRAE, IECC or local code like California’s Title 24, it’s necessary to have a legit lighting saving system, especially the occupancy and vacancy sensors.

night light

The night view is beautiful but it’s also light pollution and energy waste

Scheduled Automatic Shutoff

ASHRAE and IECC both require automatic shutoff for indoor lighting systems in commercial buildings with a size larger than 5,000 square feet.

For a large space with a predictable rate of occupancy, such as the working hour of the whole floor in the building, scheduled automatic shutoff is the way to go.

commercial building at night

Even the floor is shutoff, you can still turn on individual light by occupancy sensors

But for enclosed spaces with an unpredictable rate of occupancy, such as private offices that people would work late at night. Occupancy sensors are the ideal automatic shutoff of lighting for enclosed, localized places where they can provide a distributed control. Occupancy sensors are ideally suitable for enclosed spaces with an unpredictable rate of occupancy, such as private offices, restrooms, lunchrooms, break rooms, meeting rooms and so on.

Enclosed Space Controls(Occupancy Sensors)

ASHRAE and IECC both require lighting control in enclosed spaces, with some exceptions. We can install occupancy sensors so that both automatic shutoff and space control requirements are met.

As a result, energy codes limit the maximum control zones for space controls. 

ASHRAE requires the controlled area at 2,500 square feet if the enclosed space is less than 10,000 square feet and at 10,000 square feet if the enclosed space is greater than 10,000 square feet.

IECC requires the controlled area at no greater than 5,000 square feet and 20,000 square feet for malls, arcades, auditoriums, single-tenant retail spaces and industrial spaces or arenas where captive-key override is used.

Besides saving energy, occupancy sensors can also provide security by indicating the area is being occupied and reduce light pollution at night.

Occupancy Sensor is Convenient 

By automatically turning the light ON and OFF, people don’t have to touch the mechanical switches when entering a dark room or with a full-arm that is incompetent to turn ON/OFF the light by hand.

occupancy sensor application for laundry room

Auto turn on the lights in laundry room or garage where people are often arms-full

Natural Light Benefit Your Health

Access to sunlight is good for our health. Natural sunlight keeps us from hormonal imbalances on a diurnal basis. Occupancy sensors with light sensors allow people to enjoy the sunlight when there is ample ambient natural light without the need to turn the light on.

Occupancy Sensor Improves Security

When in dark or night, occupancy sensors can turn on the light automatically to prevent us from tripping, falling from stairs or other harms due to not having a clear sight.

Occupancy sensors can also indicate an area is full and occupied for security reasons, so we know there are people in the area beforehand.

How to Wire an Occupancy Sensor Switch

To wire an occupancy sensor is not compelicate and acutrally quite easy, homeowners can follow the steps below to install and wire your new occupancy sensor switch to replace your mechanical light switch.

You don’t need to call an electrician for the job. All you need is some common tools like a screwdriver that every home has and within 30 minutes, you can get the job done even for beginners with no electrical knowledge.

Things you’ll need:

  • A screwdriver

Things you might need:

  • A Wire cutters(to cut wires if they are too long)
  • Wire connecters
  • Electrical tape

Step 1. Turn Off Power

Turn off the breaker that controls the wallbox you are working on and test several times to ensure there is no power.

Then take off the cover plate and use a screwdriver to remove the old light switch from the wall box.

Step 2. Remove the Old Switch

Before removing the old switch, it’s better to take a look at the existing wiring to have a better idea of how they were wired, so you can apply similar wiring to your new sensor switch.

If you are a beginner, don’t worry. Take some photos first.

remove the current switch

Remember or take a photo of the previous wiring.

Even if you fail to install the new switch, you can still recover the old switch. 

Step 3. Install and Wire Occuapncy Sensor Switch

It would help a lot for installation if you could have a better understanding of how sensor switch works.

The wiring of a motion sensor light switch is 99% similar to a manual mechanical switch.

Think of it like this, a sensor switch consists of a regular switch and a sensor unit to control when to switch on and switch off. In order to allow the sensor unit to work even when the light switch is turned off, an additional complete circus is required for the control unit to work individually.

That said, the wiring is very similar to your old switch, just with some additional wires to connect for the sensor control to work.

Follow the instructions of your occupancy sensor, then you can install and wire your occupancy sensor by simply copying your old switch’s wiring.

remember the current wiring

Wiring is simple, connect the wires that have the same color.

Connect load wire(black) to load wire, line wire(red) to line wire, neutral wire(white) or ground wire(bare copper) to your light switch according to your motion sensor switch’s instructions.

connect the wires with same color

Imitate the wiring of your old switch and follow the manual

Turn on your breaker and stay away from your light switch and test whether it can detect motion.

Step 4. Fix the Switch Into the Wallbox

Partially screw the switch into the wallbox, but not too tight, then turn on the power to test if it works.

If everything works, congrats! Turn off the power and strengthen all the screws and cover the plate.