(02) 9662 1517

Warm white vs cool white: which light colour for which room

The Kelvin number on the box decides whether a room feels like a lounge or a dental surgery. Here is how to read it.

Call (02) 9662 1517Ask the showroom

In short. Warm white (2700K to 3000K) is the yellow-white of an old incandescent globe and suits living rooms, bedrooms, dining and hallways. Cool white (4000K) is a neutral white for kitchens, bathrooms, laundries, garages and offices. Daylight (5000K and above) is blue-white and belongs in workshops and retail, not in homes. The Kelvin number is printed on every globe and downlight box, and every light in one room should carry the same number.

Approximate screen rendering of each colour temperature; the showroom has them lit side by side.

What do the Kelvin numbers mean?

Colour temperature is measured in Kelvin. Lower numbers are warmer and more orange, higher numbers are cooler and bluer, which is the opposite of how the words sound. 2700K matches a traditional incandescent globe; 3000K is a touch whiter and is the most common warm white in LED fittings; 4000K is the white of a modern office; 5000K to 6500K approaches overcast daylight.

Which colour for which room?

  • Living room, bedrooms, dining, hallway: 2700K or 3000K. Skin tones, timber and warm paint colours look right, and the room reads as relaxed in the evening.
  • Kitchen bench and bathroom mirror: 4000K for the task light, so food and faces show true colour. The general light in the same room can stay warm.
  • Laundry, garage, study: 4000K. Cooler light helps concentration and shows dirt.
  • Outdoors: 3000K. Cool white on a house front looks like a car park, and warm light is kinder to neighbours and to insects.

How do I match new globes to old ones?

Read the box of an existing globe, or bring one in. If you are replacing halogen downlights with LED and the room felt right before, choose 3000K; halogen sits at about 2800K and most people find 2700K LED slightly too orange beside it. Where the paint and furniture are not chosen yet, tri-colour LED downlights with a 3000K, 4000K and 5000K switch let the electrician set the colour on the day and change it later.

Does colour temperature change the brightness?

No. Brightness is lumens, colour is Kelvin, and they are printed separately. A 4000K globe looks brighter than a 3000K globe of the same lumens because the eye reads cooler light as crisper, which is why a cool-white living room can feel harsh at night even at a low setting.

Where this fits at Cosmo

Other guides

Bring the problem to the showroom

91-93 Anzac Parade, Kensington. Monday to Friday 9am to 5pm, Saturday 9am to 4pm. (02) 9662 1517.

From the shelves

Tri-colour and warm white fittings on the shelves

Prices as shown on Cosmo Lighting's store at build time. Product photography from the supplier.

FAQ

Warm white vs cool white questions

Is 3000K warm white or cool white?

3000K is warm white. Most makers call 2700K and 3000K warm white, 4000K cool white or natural white, and 5000K to 6500K daylight. 3000K is the safe choice for living areas and bedrooms.

Can I mix warm white and cool white in one room?

You can, but it looks like a mistake unless it is deliberate: one colour for the general light and another for a task zone such as a kitchen bench. Within one layer of lighting, keep every globe the same Kelvin.

What colour are tri-colour downlights?

Tri-colour (CCT) LED downlights have a switch on the fitting that selects 3000K, 4000K or 5000K. The colour is set once at installation and can be changed later without replacing the light, which is why they suit renovations where the paint and furniture are not chosen yet.

Contact

Ask the showroom

Describe the room, the fitting or the globe and we will come back to you. For a quick answer, call the showroom in opening hours.

Ask about a light

We only use your details to reply to this message. See our privacy note.

Call the showroomAsk about a light