What happens when you swap halogen downlights for LED?

A changeover goes smoothly when the decisions are made first. Count the downlights in each room, note which switches and dimmers run them, and take a photo of one fitting. Low-voltage halogens, with small two-pin globes, have a transformer in the roof for each light or small group. Mains-voltage halogens don't, and the job is a little simpler.

Hole size is the step most people miss. You can't measure it with the fitting in place, so it's checked when the first fitting comes out, or on a quote visit. Every new fitting lists a cut-out size. Slightly larger than your holes means each one is enlarged neatly. Smaller means the trim won't cover the gap, so either the ceiling is patched or a fitting with a matching cut-out is chosen instead.

Choose colour temperature and beam beforehand, and keep each open space consistent. Our guide to choosing LED downlights covers those choices. This post is about what happens once the fittings arrive.

Most of the real work happens above the ceiling. The electrician goes up through the manhole, finds each fitting and its transformer, and checks the cable and connection at each light. Cable that has sat beside a hot halogen for years can be stiff and brittle, and a scorched joint is better found now than left under insulation.

The old fittings and transformers come out, and each new LED fitting, with its own matched driver, is connected and pushed up into the hole. Where the fitting is rated for insulation contact (IC), insulation that was cut back or pushed aside goes back over the light, closing the gaps that let heat in during summer and out in winter.

Where there's no roof space, such as the ground floor of a double storey or a low-pitched extension, the work is done from below through each hole. That's slower and gives a poorer view of the cable, so mention it when you book.

Dimmers built for halogens are the usual cause of LED flicker and buzz. An LED fitting dims through its driver, and the dimmer has to suit that driver and the number of fittings on it. A few low-wattage LEDs can fall below an old dimmer's minimum load, which is why they shimmer even at full brightness.

Plan to replace dimmers at the same time, matched to the fitting model and the count in each room. If you want smart dimmers or app control, choose them with the fittings rather than afterwards.

With the right cut-out, most holes need nothing more than a clean edge. Where the new fitting is smaller, or an old hole is damaged, the ceiling needs patching and paint. Ask how that's handled before the job starts, so you know whether a painter is needed afterwards.

It's also a good moment to rethink the layout. Halogen grids were often laid out with lights close together, and a modern fitting with a wider beam may light the room with fewer. Removing a light means patching its hole, so weigh that against the improvement.

Each light is tested on its switch or dimmer, through the full dimming range, and checked for flicker. If the fittings are colour-selectable, make sure they're set to the colour you chose before the electrician leaves.

Replacing downlights is licensed electrical work, even though it looks like a small job. Energy Safe Victoria says electrical work isn't a DIY job, even small jobs like changing power points or light switches. Lights are non-prescribed work, and the electrician must give you a Certificate of Electrical Safety.

Rental providers planning ceiling insulation under the 2027 standards should do the downlights first. That standard requires a licensed electrician to complete an electrical safety checklist and fix any electrical issues within 30 days before insulation goes in.