Does a high-CRI bulb use more energy or cost more?

A high-CRI bulb uses essentially the same energy for the same brightness. It sometimes costs a little more to buy, but the difference is usually small and well worth it in rooms where colours matter.

Does CRI affect how bright a bulb is?

No. Brightness is measured in lumens and colour warmth in Kelvin. CRI is a separate measure of how accurately colours appear, so two bulbs with the same lumens can have very different CRI.

Last updated: 19 August 2026

What is CRI (colour rendering)?

CRI, or Colour Rendering Index, is a 0-to-100 score for how accurately a light shows the true colours of the things under it. It is one of the most overlooked bulb specs — and a common reason a new LED "looks off" even when the brightness and warmth seem right.

What the number means

The reference point, 100, is natural daylight (and old incandescent bulbs), under which colours look "correct". The lower the CRI, the more washed-out, dull or slightly wrong colours appear. Cheaper LEDs often sit around CRI 80, which can make skin tones look grey, food look unappetising, and a navy jumper look black. A bulb rated CRI 90 or above renders colours richly and naturally.

CRI is not the same as brightness or warmth

This is the key point. A bulb has three separate qualities:

Lumens — how bright it is.
Kelvin — how warm or cool it looks.
CRI — how truthfully it renders colours.

You can have a lovely warm 2700K bulb that still makes a room feel flat, simply because its CRI is low. That is why swapping to a higher-CRI bulb can fix a "harsh" or "lifeless" feeling without changing the warmth at all.

Where CRI matters most

Aim for CRI 90+ anywhere you judge colours: kitchens, bathroom mirrors (for makeup), living rooms, wardrobes and anywhere you display artwork or food. For a garage, shed or storage cupboard, a standard CRI 80 bulb is perfectly fine and usually cheaper.

What to look for

Check the packaging for "CRI" or "Ra" (they mean the same thing — "Ra 90" is CRI 90). If a bulb doesn't state its CRI, assume it's around 80. When colour quality matters, spend the little extra on a 90+ bulb.