How to Choose LED Downlights: Wattage, Beam Angle, IC Rating & Spacing
Last updated June 2026. A plain-English buyer's guide to choosing LED downlights in Australia — brightness, beam angle, IC rating, cut-out, dimming and spacing. Installation by a licensed electrician.
Watts vs lumens — what actually matters
With LEDs, lumens measure brightness and watts measure power used. Don't shop on watts alone — a good 10 W LED downlight can out-shine a cheap 12 W one. As a rough guide for general lighting, aim for about 250 lumens per square metre of floor area, then add task lighting where needed.
| Downlight | Typical output | Good for |
|---|---|---|
| ~9–10 W | ~800–1000 lm | Bedrooms, hallways, general rooms |
| ~12 W | ~1100 lm | Living areas, larger rooms |
| ~15 W | ~1400 lm | Kitchens, task areas, high ceilings |
Beam angle
The beam angle sets how wide the light spreads. ~60° is the all-rounder for general room lighting. Go narrower (25–40°) for focused task light over a kitchen bench, and wider for soft, even ambient light. Adjustable gimbal downlights let you angle the beam — handy for highlighting a wall, artwork or splashback.
15W Gimble LED Downlight, Samsung Chip (Tri-Colour)
Adjustable gimbal with switchable colour temperature — strong all-rounder for kitchens and living areas.
$23.76 View product →IC rating — can it touch insulation?
IC stands for Insulation Contact. An IC-rated downlight is built to sit safely in contact with ceiling insulation without becoming a fire risk. IC-4 (also written IC-F) is the highest rating — fully covered and abutted by insulation. In a modern insulated ceiling, an IC-4 fixture is the safe, tidy choice and avoids leaving gaps in the insulation.
Cut-out size
The cut-out is the hole the downlight drops into. 90 mm is the most common residential size, so it's easy to match or replace existing fittings. Check the spec before you cut — and if you're swapping old halogens, confirm the new cut-out matches or pick a fitting with an adjustable spring range.
Colour temperature & dimming
Colour temperature sets the mood — warm white for living and bedrooms, cooler white for kitchens and work areas. Many modern downlights are tri-colour (switchable), so you can choose on install. For the full breakdown see our LED downlight colour temperature guide. If you want to dim, choose a dimmable downlight and a compatible LED dimmer — mismatched dimmers cause flicker and buzz.
Trend Unoled TL10 10W Recessed Tri-Colour Downlight
Compact recessed downlight with switchable colour temperature — a reliable all-rounder for general rooms and whole-house fit-outs.
$17.73 View product →How many downlights per room (and spacing)
Two quick methods:
- Spacing rule: space lights about 1.2–1.5× the ceiling height apart. With a 2.4 m ceiling that's roughly 2.9–3.6 m between fittings, kept at least 600 mm off walls.
- Lumens method: floor area (m²) × ~250 = total lumens needed, then divide by the output per downlight.
| Room | Approx. downlights |
|---|---|
| Bedroom (3 × 3 m) | 4 |
| Living room (4 × 5 m) | 6–9 |
| Kitchen (3 × 4 m) | 6 + task lighting |
A guide only — layout, ceiling height and furniture all play a part.
Browse LED downlights at ARCK
We carry a big range of LED downlight kits — fixed and gimbal, single and tri-colour, dimmable and IC-rated — at trade prices. Tell the trade counter your room and we'll help you pick output and quantity.
Frequently asked questions
How many downlights do I need per room?
As a guide, a 3 × 3 m bedroom suits about 4 downlights and a larger living room 6–9. Calculate it by multiplying floor area by ~250 lumens, or space fittings 1.2–1.5× the ceiling height apart.
What is an IC-4 downlight?
IC-4 (or IC-F) is the highest insulation-contact rating — the downlight can be fully covered and abutted by ceiling insulation without a fire risk. It's the safe choice for modern insulated ceilings.
What beam angle should I choose?
Around 60° suits general room lighting. Go narrower (25–40°) for focused task light over a bench, and use adjustable gimbal fittings where you want to aim the beam.
Are watts or lumens more important for LED downlights?
Lumens — they measure actual brightness. Watts only tell you power draw. Compare lumens between fittings, aiming for roughly 250 lumens per square metre for general lighting.
Need a hand choosing? Call the trade counter on (02) 9890 9693 or drop in to 589 Church St, North Parramatta. Order online for free Click & Collect, with metro delivery from $19.90 calculated at checkout.