Energy efficient mains light bulbs

[David Schweizer]

The Tesco's warm white LED bulbs that I fitted are neither "gloomy" or "brown". They seem to replicate the old traditiomal Tungsten bulbs, and are fine for working or reading, just a bit brighter.

[blackrose]

Well the difference between the brightness of warm white and cool white LEDs would be reflected in their lumen output specifications and according to Screwfix there's no difference.  Maybe it's just the 12v bulbs that are different, or maybe it depends on the particular brand? Or maybe Screwfix have their figures wrong!

 

I personally prefer warm white. I just find the cool white light too sterile for me, but each to their own.

 

Edited May 7, 2023 by blackrose

[Alan de Enfield]

18 minutes ago, blackrose said:

Well the difference between the brightness of warm white and cool white LEDs would be reflected in their lumen output specifications and according to Screwfix there's no difference. 

 

 

 

For me the 'cool' whites are much sharper, clearer and 'brighter'

It is not all about Lumens - The K factor is just as important.

 

Contrary to popular belief a higher colour temperature is not a measurement of brightness but appearance, brightness is measured in lumens. Because LEDs are blue to begin with, more phosphor is coated over the LED to provide the warmer colour temperatures; which does make the cooler colours appear slightly brighter. Generally cool white is around 5% brighter than warm white in terms of lumens.

Here are the main three colour temperatures used in modern day LED lights such as retrofit LED light bulb lamps and downlights:

• Extra warm white 2700K
  Similar to a traditional incandescent light bulb or halogen. A 2700K LED will still appear slightly whiter than a halogen but is more orange in appearance than the other colour temperatures. This is sometimes called 'soft white' by people in the trade. Extra warm white is not always an option with some brands of integrated LED downlights, so if you know you want this colour temperature you can narrow down your search to just a few options. If you like the cosier setting for your living room, this option can be taken a level further with DimTone dimming. DimTone reduces the colour temperature as its dimmed in brightness, mimicking the effects of a halogen and creating a more ambient, relaxing vibe.
   
• Warm white 3000K
  Clearer in appearance but still quite warm. This has become the 'new norm' for general lighting and is by far the most popular choice that we sell. Not too warm and not too cold.
   
• Cool white 4000K
  A much clearer and whiter appearance that is predominantly used in commercial locations like super markets and offices. Cool white appears brighter than warm white meaning it's also more energy efficient. It can make a room feel cold and clinical but when used in the right environment it can make a room appear more modern and cleaner. This is also referred to as neutral white or cold white but as long as the Kelvin rating is the same then it can be called whatever you like. This is a popular option for kitchens and bathrooms. If you want a relaxing bath, can you really relax with cool white?
   
• Daylight 5000K-6500K
  This goes a step beyond cool white, adding more of a blue tinge to the environment. Too harsh for some, but adored by others.

When comparing colour temperatures, you won't be able to fully appreciate the dramatic difference that each tone offers until a room is fully illuminated with one of them. Just testing a sample will give you an idea of the difference but until you've seen a room fully lit in one of the colours, only then will you truly understand the difference.

Each option also accents the colours of your walls, floor and surrounding area. If your kitchen has grey walls and cupboards, the cool white version could make your room appear too clinical like a doctors surgery. Compared to 3000K which makes less of a statement.

The images below show the impact that can colour temperatures can have in the same kitchen:

 

 

 

 

 

Warm Light vs. Daylight on the Kelvin Scale

Warm light is actually much dimmer than daylight, about 2,700 on the Kelvin scale compared to 5,000 or more for daylight. Daylight is great for reading and is often mimicked in places like medical examination rooms, where clear vision and attention to detail are important.

Cool Light vs. Daylight on the Kelvin Scale

Cool white light is just one step down from daylight on the Kelvin scale, at about 4,000K compared to 5,000 or more for daylight. Natural daylight comes from radiation emitted by the sun, while artificial light such as cool light relies on halogen gas or a filament powered by electricity to create light.

 

Edited May 7, 2023 by Alan de Enfield

[cheesegas]

CRI is also important when buying LEDs - it’s effectively a measure of what range of frequencies of light it emits. A low CRI light source will cause your eyes to render colours weirdly and can cause eye strain, things just look ‘odd’ but you can’t work out why, despite there being plenty of light.
 

Cheap LEDs often have a low CRI and often aren’t even tested for it, so the info isn’t listed.  

 

https://www.flexfireleds.com/color-rendering-index-cri-and-led-lighting-what-is-cri/