- Warm white looks like old incandescent bulbs – soft and golden, around 2,700 to 3,000 K.
- Cool or pure white is crisper and bluer; the higher the Kelvin number, the bluer the light.
- Do not mix warm and cool whites on one house – side by side, the warm looks yellow and the cool looks blue.
- Permanent RGB and RGBW systems let you change colour from an app instead of choosing once.
What the numbers mean
The colour of white light is measured in kelvin (K). Lower numbers look warmer and more yellow; higher numbers look cooler and bluer. Typical values:
| Colour temperature | What it looks like |
|---|---|
| About 2,700 K | Soft white – the glow of a traditional incandescent bulb |
| About 3,000 K | Warm white |
| About 6,500 K | Daylight – a cool, bluish white |
Values from Wikipedia's colour temperature reference. Christmas light brands label their whites differently – look at the bulbs at night.
Warm white
The classic look, and the closest to the incandescent strings many people grew up with. It flatters brick, stone and wood, and suits traditional homes. If you are unsure, warm white is the safe choice for a roofline.
Cool or pure white
Crisper and more modern, with an icy feel that suits contemporary homes, white or grey siding and snowy climates. It can look harsh on warm-toned brick, so see a sample on your house before committing to a whole roofline.
Multicolour
Playful and nostalgic, and it hides small imperfections in a layout better than white does. Multicolour works well on trees and bushes even when the roofline is white – a common professional combination.
Rules that avoid the most common mistakes
- One white per house. Warm and cool whites side by side make each other look wrong.
- Buy all your white bulbs together. LED whites can vary between batches and brands.
- Judge at night. Ask an installer to show you a sample bulb on your house after dark.
- Match the architecture. Warm white for traditional materials, cool white for modern ones.
Not ready to choose?
Permanent lighting systems use RGB or RGBW LEDs, so you can run warm white most of the year, red and green in December and team colours on game day – all from an app. 578 installers in our directory offer them.
Keep reading
- C7 vs C9 bulbs
- When to put up and take down Christmas lights
- HOA rules for Christmas lights
- Permanent Christmas lights
Sources
- Wikipedia – Color temperature – read September 22, 2026
Written by the Christmas Lights Outdoor Installation editorial team. Figures are dated and linked to their source; national numbers vary by area – confirm with local installers.
The directory
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