Cutting lighting energy: LEDs, sensors, timers and dimmers

Lighting energy is the power each light draws multiplied by how long it is on. A row of halogen downlights in a kitchen running every evening uses far more over a year than a bright light in the shed switched on twice a month. Start with the lights on longest: the kitchen and living areas, outdoor and security lights, and anything left on overnight.

Walk around one evening and count. Plenty of older homes have a grid of halogen downlights added during a renovation, often more than the room needs, plus floodlights or garden lights that run all night.

Then look for the plain waste: lights on in empty rooms, outdoor lights burning in daylight, and the laundry or garage light that nobody remembers to switch off.

The Australian Government's energy.gov.au says LEDs use about 75% less energy than halogen globes and last 5 to 10 times longer. That makes halogen downlights the first target in most homes.

Putting an LED globe into an old halogen fitting keeps the housing, the transformer and the need for a gap in the insulation, and it can flicker because many old transformers weren't built for such a small load. A complete LED fitting with its own matched driver takes the transformer out, runs cooler and, if it is IC-rated, can sit under insulation. Closing those insulation gaps helps the heating and cooling as well.

For plain mains lampholders in battens, pendants and older ceiling roses, a good LED globe or a new LED oyster fitting is often all that is needed. Old fluorescent battens in garages and laundries can be replaced with LED battens.

Halogen grids were often laid out to make up for each globe's narrow beam. Modern LED downlights spread light differently, so a changeover is a chance to fit fewer, better-placed lights instead of swapping one for one.

Task lighting, such as strip lighting under kitchen cabinets or a reading lamp beside the couch, lets the main lights stay off or dimmed. A room lit in layers uses less power than one where every downlight goes on just to see the bench.

Keep the colour consistent while you're at it. One warm or neutral white per space, from a single range, looks far better than a mix of whites from different brands.

Motion sensors suit places people pass through or forget about: garages, laundries, walk-in robes, hallways, pantries and outdoor paths. Set the hold time long enough that the light doesn't switch off on someone standing still at the bench.

Outdoor sensor lights with a daylight sensor only come on after dark. A floodlight that stays on constantly, or triggers on every passing car, usually needs its sensitivity or aim adjusted rather than replacing.

Garden lighting, porch lights and feature lighting suit timers or photocells that switch on at dusk and off at a set hour, instead of burning until morning. Smart switches can run schedules too, and some adjust automatically as sunset moves through the year.

Garden lights left on all night are one of the easiest savings in the house, because nobody is looking at them at 3am. A timer that switches them off at bedtime keeps the look in the evening without paying for the dark hours.

Dimming an LED reduces its power use, so a living area that is dimmed most evenings uses less. The catch is matching. LED drivers generally prefer trailing-edge dimmers, and a mismatched dimmer can cause flicker, buzzing or lights that won't dim smoothly.

Smart switches add schedules, scenes and the ability to check from your phone whether the garage light is still on. A smart globe needs the wall switch left on, so it suits a lamp rather than a room full of downlights.

Fitting a dimmer or smart switch is electrical work. Energy Safe Victoria says electrical work isn't a DIY job, even for small jobs such as changing a light switch.

You don't have to change every light at once. Start with the lights on longest, usually the kitchen and living areas, then the outdoor lights, then sensors in the garage and laundry. Each stage pays its own way.

In older homes, changing fittings opens light points that may not have been touched in decades. Energy Safe Victoria lists old switches and flickering lights among the signs of faulty wiring and advises having the wiring checked in houses over 30 years old. Brittle cable found at a light point is best replaced, not reused. Lights are non-prescribed electrical work, and whenever a licensed electrician completes electrical installation work, they must give you a Certificate of Electrical Safety.

Renters can still make a difference: LED globes in plain lampholders and plug-in lamps for task lighting are easy changes, and anything wired in is a conversation with the rental provider.