Guide

Downlights Too Cold? How to Choose Between 2700K, 3000K and 4000K

A lot of people describe new LED downlights as cold, harsh or "like an office". Usually two different things get mixed up: the colour of the light and how sharp it is. They have completely different fixes, so it pays to work out which one is actually bothering you.

If it is the glare that bothers you, the quickest fix that needs no tools is a shade over the downlight, such as Lumeaglow. It makes the light softer, and only a little warmer, but it does not replace a warmer bulb. Below we separate the colour of the light from how sharp it is, and which fix does what.

What kelvin means

Colour temperature is given in kelvin (K) and is shown on the box, the bulb or the fixture's data sheet. A low number means yellower, warmer light. A high number means whiter, cooler light.

• 2700K: warm, yellowish white, close to what many remember from old incandescent bulbs.
• 3000K: a little whiter, but still warm.
• 4000K: neutral white, common in offices and utility rooms.
• 5000–6500K: cool, bluish white.

"Warm white" is often used for both 2700K and 3000K. If you want to know what you are getting, look for the number.

Cold light or glare?

Turn off everything else and look at a white wall with only the downlights on. If the wall looks bluish or grey, colour temperature is the problem. If it is more that your eyes sting when you look towards the ceiling, or you see sharp points of light in shiny surfaces, that is glare.

• Light that is too cold is fixed with a lower kelvin.
• Glare is fixed by shielding or spreading the light source.

Many rooms have both. And warm light still glares if you look straight into a bare LED.

How to get warmer light from your downlights

1. Replaceable bulbs, such as GU10: Buy bulbs with a lower kelvin. 2700K suits living rooms and bedrooms, 3000K if you want slightly fresher light in the kitchen or bathroom.
2. Built-in LED with a colour temperature switch: Some downlights have a small switch that lets you choose between, say, 2700, 3000 and 4000K. Check the data sheet for your model. If the switch sits behind the fixture inside the ceiling, an electrician can change it for you.
3. Smart downlights: You set the colour in the app, and many can go warmer in the evening.
4. Built-in LED with no switch: The colour is fixed. To get a different kelvin, the fixture has to be replaced.

Colour rendering is something else

Colour rendering is given as CRI or Ra and describes how natural colours and skin tones look under the light. It has nothing to do with kelvin. Two 2700K bulbs can feel quite different if one renders colour poorly. If you are buying new bulbs for a bathroom or kitchen, it is worth looking for CRI 90 or higher.

What a shade can and can't do

A shade over the downlight, such as Lumeaglow, is made for glare. It turns the small, sharp point into a larger surface of light and spreads the light across the ceiling, so it feels softer and the room calmer.

The shade makes the light a little warmer, but only a little. It does not replace a warmer bulb. If the light is too cold, the fix is still a bulb, a switch or a new fixture. If you have both cold light and glare, warmer light plus a shade together make the biggest difference.

Room by room

• Living room and bedroom: 2700K, ideally with lamps at seating height.
• Kitchen: 2700–3000K is common. Under-cabinet lighting gives better task light than cooler downlights.
• Bathroom: 2700–3000K, with light from the sides at the mirror. See the bathroom downlights guide.
• Hallway and utility room: a slightly cooler light is fine here if you prefer it.

In short

• Kelvin tells you how warm or cool the light is. A lower number means warmer light.
• Cold light and glare are two different problems with two different fixes.
• A shade reduces glare and makes the light only a little warmer. It does not replace a warmer bulb.

If glare is what bothers you most, there are more fixes in how to soften harsh LED downlights and downlights feel too harsh?.

Frequently asked questions