Two lamps can give off the same amount of light and still change a room in opposite ways. The difference is colour temperature: one number on the spec sheet, usually followed by a K. Here is what it means, and how we choose it for each piece.
What the number means
Colour temperature describes the colour of a light source as the temperature, in kelvin, that an ideal glowing body would need to reach to give off light of the same colour. It sounds backwards, but it works simply in practice: low numbers look warm, yellow and amber; high numbers look cool and blue. Light below about 3000K reads as warm, 3500-4100K as neutral white, and above 4100K as cool, blue-tinged white.
| Light source | Approximate colour temperature |
|---|---|
| Candlelight | About 2000K (candle flames range from about 1800K to 2900K) |
| Incandescent bulb | About 2650K (40 W) to 2900K (100 W) |
| Halogen bulb | About 2800-3200K |
| Neutral white | 3500-4100K |
| Midday summer sun | About 6000K |
The four warm whites we use
| Colour temperature | What it looks like | Our pieces |
|---|---|---|
| 1800K | The warmest we offer, a deep, candle-like amber | Aureole Sun VXS (option) |
| 2000K | Ultra-warm white, a low, golden glow | U·013 wall light, U·021 and U·037 ambient lamps |
| 2200K | Warm amber, a little less deep than 1800K | Aureole Sun VXS (option) |
| 2700K | Warm white, the colour of a classic household bulb | U·016 and U·018 table lamps, U·039, U·044 and U·048 pendants, Aureole Sun VXS (option) |
None of them goes near neutral or cool white.
Which one where
- Living rooms and evenings: 2000K. The ambient lamps U·021 and U·037 and the U·013 wall light glow low and golden. They set the mood rather than light a task.
- Tables, reading and cooking: 2700K. The table lamps and pendants are 2700K, warm but clear enough to read a menu, a book or a recipe by.
- Statement walls: 1800K to 2700K. The Aureole Sun VXS is fitted with the colour temperature you choose and tested before it leaves the studio. Choose 1800K for a candle-like amber, 2700K to match the U· table lamps and pendants in the same room.
- One room, one family. A 2000K wall light and a 2700K pendant sit happily together: both are warm. A cool white ceiling light in the same room can pull against them.
Colour rendering: does warm light show colours truly?
Colour temperature tells you the colour of the light. Colour rendering tells you how faithfully it shows the colours of the things it lights. The usual measure is CRI, and a CRI above 80 is generally considered accurate. Every U· piece is CRI 90+, so a warm light still shows a fabric, a painting or a plate of food as it is.
Dimming
Every U· piece is dimmable. Use a dimmer suitable for LED lighting, and ask us if you are not sure which. On the Aureole Sun VXS, use only G9 LED bulbs of the type and wattage supplied, never halogen.
Questions
What colour temperature is warm white?
On our pages, warm white is 2700K and ultra-warm white is 2000K. In general, anything below about 3000K reads as warm.
What is the difference between 2000K and 2700K?
2000K is lower, so it is warmer and more golden, closer to candlelight. 2700K is the warm white of a classic household bulb, a little clearer and better for reading or eating by.
Can I change the colour temperature of a U· piece?
No. The LED is integrated, so each piece has its own fixed colour temperature: 2000K on U·013, U·021 and U·037, 2700K on the table lamps and pendants.
Which colour temperature should I choose for an Aureole Sun VXS?
1800K for the warmest, candle-like amber, 2200K for a slightly lighter amber, 2700K to match a classic warm white or the U· table lamps and pendants. We fit the one you choose and test it before it ships.
Does warm light make colours look wrong?
Not with good colour rendering. U· pieces are CRI 90+, above the level generally considered accurate.
Sources Colour temperature, MFA Cameo · Colour temperature, Philips Lighting · CRI and colour temperature, Buildings
