Finding the Right Light Bulb

Finding the Right Light Bulb

Choosing the right light bulb can be tricky. Lumen, watt, colour temperature … what do these and other terms mean? Our helpful guide to light bulbs will give you a quick and easy overview of “what’s what” in lighting and will help you to find the right bulbs for every fixture in your home.

Cap Types

When you are choosing a bulb to fit a particular light or lamp in your home you will first need to make sure you choose the right cap type. The cap is the bridge between the bulb and the power-source fitting, providing just the right amount of current to make the bulb glow. But one size does not fit all and as there are different types of caps, you need to make sure that they fit your light fixture.

The most common are screw bases like the E27 for big fittings and the E14 for small fittings like candles and lustres. There are also specific caps like the GU10 and GU5.3 for spots, downlights or other special light fittings–GU10s were traditionally available only as a halogen bulb but LED variants are now available. Plus there are also B22d and B15d bayonet bulbs that are used in smaller fittings and finally low-voltage G4 and mains-powered G9 halogens.

See below to see what the different cap types look like  

Light Bulb Technologies

Halogen Bulbs

Halogen Lights deliver the highest standards of light quality, giving natural, clear, sparkling and warm light:

• Fully dimmable

• More energy efficient than “classic” bulbs

• Short warm-up time

In short, they are the perfect choice if you are looking for the quickest and easiest way to replace classic bulbs throughout your home and still want to enjoy the same quality of clear, warm and sparkling light that you are used to.

LED Bulbs

Without compromising quality, LED light bulbs offer unlimited lighting possibilities. They combine state-of-the-art technology with familiar design as they are available in the all the same shapes as classic bulbs:

• Longest lifespan of any bulb–up to 25 years    

• Short switching cycles

• Very small energy consumption

If you are looking for the most sustainable lighting solution, LED bulbs are the ideal choice for you.

Energy Saving Bulbs

Energy-saving bulbs, also known as compact fluorescent (CLFs), are a very economical choice for use in the home and offer the perfect range of high-brightness functional lighting for interiors like work spaces, kitchens and living rooms:

• Very low energy consumption (80 per cent less than conventional bulbs)

• Long lifespan                                                               

• Available in different colour temperatures

If you are looking for an easy way to save energy and reduce your lighting bills, energy savers are a great choice.

Dimmable Bulbs
It is important to remember that dimmers require dimmable bulbs, so keep this in mind when you are choosing your bulb. In the past, older types of energy-saving bulb tended not to be dimmable; however these have now been replaced with a new generation of non-flicker models that are also dimmable. Halogen bulbs are generally easy to control

with a dimmer switch, however, not all LED lighting is designed to be dimmable, and using a non-dimmable bulb with a dimmer switch can cause the bulb to not work properly or fail completely. So if you want to buy a dimmable bulb, make sure you check the product details to see if it will work with a dimmer.

Colour Temperature

Modern bulbs can offer different colour temperatures, which are indicated in a unit called Kelvin (K). The colour temperature helps you create different moods–bulbs with a low Kelvin value generate warm, yellow light, which produces a relaxing mood, perfect for creating a cosy atmosphere in your home. Bulbs with a high Kelvin value produce cool, blue light for a more energizing mood and are ideal when you need to perform tasks that require concentration.





1,000K Candlelight Red/Yellow Very Warm
2,700K-3,000K Conventional Lamp – Yellow Warm White
4,000K-5,000K Halogen/CFL – Blue Cool White
10,000K Blue Sky – Blue Very Cool

Watts & Lumens

Most people think that the wattage (W) of a bulb tells you how much light it gives. However, this is not the case as wattage only measures the amount of energy required to light bulbs. Lumens (lm), on the other hand, measure the amount of light that is actually produced. For example, some bulbs, like LED, give the same light output (in lumens) as a classic bulb, but for a much lower wattage. So, to see how bright a bulb is, think in lumens, not watts. The higher the lumen value, the greater the light output.

25 W 230 – 270 lamp
35 W 250 – 280 spotlight 390 – 410 lamp
40 W 440 – 460 lamp
50 W 330 – 350 spotlight
60 W 800 – 850 lamp

Switch Cycles

Every bulb can only be switched on and off a certain number of times before it fails. This is known as the ‘switch cycle’. The room a bulb is being used in can make a big difference to its lifespan. For example, bulbs in a living room often stay on all evening, whereas those in a bathroom may get switched on and off much more regularly. Think about which bulb best fits the room you’ll be using it in. Halogen bulbs typically have a switch cycle of 8,000, energy savers up to 30,000 and LED bulbs about 50,000.

Colour Rendering Index

Colour rendering, expressed as a rating from 0 to 100 on the Colour Rendering Index (CRI), describes how a light source makes the colour of an object appear to human eyes and how well subtle variations in colour shades are revealed. Natural outdoor light has a CRI of 100 and is therefore the standard of comparison for any other light source. The higher the CRI, the more natural the colours appear.

Wide & Focused Light

The shape of a bulb has a big impact on the light effect it delivers. This is because the shape determines the width of the light beam. Standard bulbs can achieve a 360-degree distribution of light (see example on the left), whereas spots can deliver a focused light distribution at a 25 to 35-degree beam angle. So keep in mind the width of the area you want to illuminate when choosing your bulb.