You’ve found the light. It’s perfect — right shape, right finish, right price, and you can already see it hanging over the dining table.
Before you buy it, check one thing: can it actually be installed where you want it, and will it work with what’s already there?
That sounds obvious. It’s the single most common reason we turn up to install a fitting and can’t.
The one thing: dimmer compatibility
If the light is going on a dimmer — and most people want dimmers — this is the check that matters.
LED lights and dimmers are frequently incompatible, and the symptoms are miserable: flickering, buzzing, a narrow dimming range where nothing happens for the first half of the travel, lights that won’t turn off completely, or a fitting that fails early.
The reason: old dimmers were designed for incandescent globes drawing 60 or 100 watts. An LED draws 5 to 10 watts. Many dimmers have a minimum load they need to see in order to work properly, and a couple of LEDs don’t get anywhere near it. On top of that, LED drivers come in leading-edge and trailing-edge varieties, and they need a dimmer that matches.
What to check before you buy:
- Is the fitting marked as dimmable at all? Plenty aren’t, and putting a non-dimmable LED on a dimmer will destroy it.
- Does the manufacturer publish a compatibility list of tested dimmers? Good brands do. That list is the answer.
- Is your existing dimmer leading-edge or trailing-edge, and does it match?
- How many fittings are on the circuit, and does that meet the dimmer’s minimum load?
The usual fix is a modern trailing-edge LED dimmer with a low minimum load. It’s an inexpensive part. What isn’t inexpensive is buying twelve downlights that flicker and discovering the problem after they’re all installed.
If you take one thing from this article: check the dimmer compatibility list before you buy the fitting, not after.
The other things worth checking
Cutout size
For downlights, the cutout is the hole in the ceiling. Different fittings need different sizes.
If you’re replacing existing downlights, measure the existing hole first. A new fitting with a smaller cutout means patching and painting every single position — which turns a two-hour job into a two-day job with a plasterer involved.
Manufacturers publish cutout sizes. Match them, or accept the patching.
IC rating and insulation
Downlights generate heat. Ceiling insulation traps heat. Getting this combination wrong is a documented fire risk.
Fittings marked IC or IC-F can be covered by insulation. Anything else needs clearance around it, and the insulation has to be held back.
This matters especially if your home has been insulated after the lights went in — a very common scenario in Melbourne homes that have had energy upgrades. We find batts pushed up against non-rated fittings regularly.
Ceiling depth
Some fittings — particularly larger downlights and anything with an integrated driver — need more depth above the ceiling than you’d think.
In a single-storey home with a decent roof cavity, no problem. Between floors of a double-storey, or under a concrete slab, or in a home with a very shallow roof pitch, depth can be genuinely limiting. Worth checking before you commit.
Weight and fixing
Anything heavy — a large pendant, a chandelier, a ceiling fan — needs fixing to structure, not to plasterboard.
If there’s no joist or noggin where you want it, someone has to get into the ceiling to install one. That’s fine if you know in advance. It’s a problem if the light is already unwrapped.
Zone rating for wet areas
Bathrooms, laundries and outdoor areas have zone requirements. A fitting near a shower needs an appropriate IP rating; a decorative pendant designed for a bedroom does not belong over a bath.
This applies to vanity lighting too — it’s close enough to water to matter.
Colour temperature and CRI
Not a compliance issue, but the difference between a room that looks right and one that doesn’t.
Keep colour temperature consistent across a space. 3000K is our usual recommendation for living areas and kitchens; 2700K for bedrooms and lounges where you want it warmer. Mixed temperatures in one room look like an error.
CRI 90+ where colour matters — kitchens, bathrooms, anywhere you’re looking at food or your own face.
Some fittings are also tuneable, shifting warmer through the evening. Nice to live with if you’re specifying from scratch.
Whether you can still buy it in three years
The unglamorous one. If you install ten of something and two fail in 2029, can you still get a match?
Established brands with long product lines are worth the premium for exactly this reason. A discontinued fitting means either living with a mismatch or replacing the lot.
The five-minute version
Before you buy:
- Dimmable? And is your dimmer on the compatibility list?
- Cutout size — does it match what’s already in the ceiling?
- IC rated if there’s insulation up there?
- Enough depth above the ceiling?
- Fixing — is there structure where you want it?
- Correct zone rating for a wet area?
- Colour temperature consistent with the rest of the room?
Send us the product page before you order. It takes us two minutes to look at a spec sheet and tell you whether it’ll work, and it’s saved plenty of people a return trip to the lighting shop.
Talk to us
We do lighting design and installation across Melbourne’s eastern suburbs, and we’re happy to be brought in before anything’s purchased.
Registered Master Electrician. Over 200 five-star Google reviews. Lifetime workmanship warranty.
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