Kelvin, Lumens and Watts – Everything You Need to Know

Kelvin, Lumens and Watts – Everything You Need to Know

Understanding the Brightness of Your Lighting

Understanding the Brightness of Your Lighting

Choosing a light bulb is no longer simply about selecting the right wattage. Today, several factors determine the quality and performance of your lighting, including lumens, kelvins, watts, the type of bulb base, dimmability and even the bulb shape.

In this guide, you’ll learn what these terms mean and how to choose the ideal LED bulb for every room in your home.

What Does Kelvin Mean?

What Does Kelvin Mean?

Kelvin (K) is the unit used to measure the colour temperature of a light source. It does not indicate brightness, but rather the colour of the light emitted.

Colour temperatures generally range from 1,800 K to 16,000 K.

The lower the Kelvin value (below 3,000 K), the warmer and more yellow the light appears, creating a cosy and relaxing atmosphere.

Conversely, the higher the Kelvin value (above 5,000 K), the cooler and whiter the light becomes, making it ideal for workspaces and areas requiring maximum visibility.

Choosing the right colour temperature allows you to create the perfect atmosphere for every room.

Colour Temperature

Light Colour

Recommended Use

1800–2700 K

Very warm white

Living room, bedroom, restaurants

2700–3000 K

Warm white

Living spaces, dining room

4000 K

Neutral white

Kitchen, office

5000–6500 K

Cool white

Workshop, garage, technical spaces

1800 to 2700 K – Very Warm White

Light type: Very warm white
Recommended for: Living room, bedroom, restaurant.

2700 to 3000 K – Warm White

Light type: Warm white
Recommended for: Living room, dining room.

4000 K – Neutral White

Light type: Neutral white
Recommended for: Kitchen, office.

5000 to 6500 K – Cool White

Light type: Cool white
Recommended for: Workshop, garage, technical workspace.

Watts

Watts

Watts (W) indicate the amount of electrical energy consumed by a light bulb.

In the past, wattage was used to estimate the brightness of incandescent bulbs. With modern LED technology, this is no longer the case.

An 8-watt LED bulb can now produce the same amount of light as a traditional 60-watt halogen bulb, while using significantly less electricity.

Today, watts are mainly used to measure a bulb’s energy consumption rather than its brightness.

Lumens and Lux

Lumens and Lux

A lumen (lm) is the unit used to measure the luminous flux, or the total amount of light emitted by a bulb or luminaire.

The higher the number of lumens, the brighter the light.

A lux (lx) measures the amount of light actually received on a surface.

1 lux = 1 lumen per square metre.

Different activities require different lighting levels.

Activity

Recommended Illuminance

Hallway

100–150 lux

Living room

150–300 lux

Kitchen

300–500 lux

Office

500 lux

Workshop

750–1000 lux

To summarise:

  • Lumens describe the amount of light produced by a bulb or luminaire.
  • Lux measures the amount of light that reaches a surface, such as a desk, worktop or floor.

How to Choose the Right Light Bulb

How to Choose the Right Light Bulb

Looking to reduce your energy consumption? Choose an LED light bulb.

Compared to halogen bulbs, LED bulbs consume up to ten times less electricity while offering an impressive lifespan of up to 50,000 hours, depending on the model.

When selecting an LED bulb, several important criteria should be considered.

Bulb Type and Base

Bulb Type and Base

LED bulbs are available with various types of bases.

The base is identified by a letter followed by a number indicating its diameter or fitting type.

The most common bases are:

Base

Typical Applications

E27

Pendant lights, ceiling lights, floor lamps

E14

Table lamps, wall lights

GU10

Spotlights

G9

Decorative designer lighting

G24

Commercial lighting

E39 / E40

Industrial and public lighting

Always check your luminaire’s required base type before purchasing a replacement bulb.

Power and Brightness

Power and Brightness

The brightness of an LED bulb should be selected according to the size of the room, ceiling height and the desired lighting effect.

Today, it is recommended to compare bulbs using their lumen output rather than their wattage.

For a cosy atmosphere, choose a bulb with fewer lumens.

For workspaces or larger rooms, select a bulb with a higher lumen output.

Colour Temperature

Colour Temperature

Light bulbs are generally available in three main colour temperatures:

  • Warm White
  • Neutral White
  • Cool White

These are expressed in Kelvin (K).

For living rooms and bedrooms, 2700 K to 3000 K provides a warm and comfortable atmosphere.

For kitchens, offices and workspaces, 4000 K offers excellent visual comfort.

Above 5000 K, the light becomes cooler and is particularly suitable for workshops and technical environments.

Dimmable or Non-Dimmable LED Bulbs

Dimmable or Non-Dimmable LED Bulbs

Dimmable LED bulbs allow you to adjust the light intensity using a compatible dimmer switch.

This enables you to create the perfect atmosphere while helping to optimise your energy consumption.

Please note that not all LED bulbs are dimmable, so always check the product specifications before purchasing.

Bulb Shape

Bulb Shape

LED bulbs are available in many different shapes, including:

  • Globe
  • Standard
  • Candle
  • Reflector
  • Tube
  • Capsule
  • Spiral
  • PAR
  • AR111

The ideal shape depends on the design of your luminaire, the desired aesthetic and the intended application.

RGB LED Bulbs

RGB LED Bulbs

RGB LED bulbs are equipped with infrared, wireless or Bluetooth receivers, allowing you to change the light colour using a remote control or smartphone app.

RGB stands for:

  • R = Red
  • G = Green
  • B = Blue

By combining these three primary colours, millions of different shades can be created.

Many advanced RGB bulbs also allow you to adjust the colour temperature, brightness and create customised lighting scenes to suit every mood and occasion.

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