Australian homes account for 13% of Australia's total energy use and about 10% of its greenhouse gas emissions. One simple way to save both the environment and your electricity bill is to enlist the help of motion detector controlled lighting systems. Necessity-based lighting optimizes lighting use and can save up to 60% of a household’s energy consumption, especially if you live in a house full of children. Sensors work equally well inside and outside.Outdoor motion sensors are excellent for switching lights on to scare wild animals and to detect both wanted and unwanted human presence when someone approaches your home. They can use conventional electricity, can be battery operated or solar powered as they offer both security and convenience for home owners. There are a number of excellent solar lighting options around and the beauty of solar is that the lights and sensors are self powered so they can be pretty much placed anywhere, as long as they get sunlight during the day.Security motion sensors work on similar principals to outdoor sensors, usually installed to detect humans at home entry points and vehicles in your driveway. They are typically equipped with smart floodlights instead of standard exterior lights to alert home owners to visitors (or in not so positive cases, intruders) and light up the area, signal to ring a bell to chime or to set off a burglar alarm.Indoor motion sensors work on the same premise as outdoor, with wireless occupancy sensors detecting human presence in a room, hallway or any other area of the house and activating the lights accordingly. Lights automatically turn off as people leave the area. Motion sensors work both mechanically and electronically. Mechanical motion detection works in the form of a switch or trigger based on a simple binary code concept. Electronic motion detection employs optical and acoustical detection to activate alarms, cameras, lights and even doorbells. Energy is best saved by installing the motion sensors in low-trafficked areas of a home like garage, bathrooms, porch, stairwell, basement or attic, entry points, laundry room, closets, guest room and storage areas.See also: The Best Way to Use Lighting Switches and Controls.Image: Martynova Anna/Shutterstock