Sensors are a great way to ensure lights are only used when needed. 

Why?
Maximising the use of daylight with sensors could save around 15% on your lighting costs.
Installing controls that automatically turn off lights when they’re not needed could save you up to 30%.

How?
Daylight sensors detect natural light levels and switch off lights or control dimming accordingly.  It may be most cost effective to apply these only to the lights nearest the windows, leaving the rest on manual control.
Movement (or ‘occupancy’) sensors are particularly suited to intermittently used areas such as rest rooms, kitchens and storerooms. The use of a time delay ensures occupants can safely leave without being plunged into darkness. It also ensures lights are not constantly being switched on and off. ‘Absence detecting’ is suited to an office environment, where lights are switched on manually but the sensor turns them off when the space becomes unoccupied, so the office isn’t lit unnecessarily.
In some areas, the best option is to a combination of occupancy and daylight sensing. Combined detectors are widely available but are more expensive.
To find a local electrician that has experience in this field:
- contact NECA (National Electrical & Communications Association) on 03 9645 5566 or at www.neca.asn.au/index.php/site/find_an_electrician
- or visit the EcoSmart Electricians website www.ecosmartelectricians.com.au

How did we calculate this?
The carbon savings depends on how many lights are controlled by sensors, the type of sensor, the occupancy of the room and the available daylight.
For example, if a business has a store room lit by 20 x 36W T8 fluorescent tubes (connected load 47W each) which only need to be switched on for 70% of the time, the saving would be:
20 x 0.047kW x 2,000 hours x 30% = 564 kWh per year. This equates to 773 kgCO2e per year.

Cost to implement
Sensors can cost less than $100, and come in a range of types, for example, passive infrared, microwave, or ultrasonic. Installed costs are estimated at $80 per sensor.

For more information visit:
- Carbon Compass www.carboncompass.com.au/solution/cityswitch-green-office-program
- For further guidance on how to implement lighting controls, see www.carbontrust.co.uk/publications/pages/publicationdetail.aspx?id=CTL033

To watch a video on how daylight sensors work, see www.carbontrust.co.uk/cut-carbon-reduce-costs/products-services/technology-advice/Pages/lighting-daylight-sensors.aspx

For occupancy sensors www.carbontrust.co.uk/cut-carbon-reduce-costs/products-services/technology-advice/Pages/lighting-occupancy-sensors.aspx

To find a local electrician that has experience in this field:
- contact NECA (National Electrical & Communications Association) on 03 9645 5566 or at www.neca.asn.au/index.php/site/find_an_electrician
- or visit the EcoSmart Electricians website www.ecosmartelectricians.com.au