Light bulb guide.

Having trouble understanding what bulb you need or what type would best suit your room and your needs? We’re here to help as we understand how confusing the world of lighting can be with all the different options available on the market today. We’ve put together a simple, easy to follow guide informing you of all your options, so you can decide which is the best choice for you and your lamp or light fitting.

Find your cap fitting.

Before buying bulbs, you need to determine what cap type your light fixture or lamp is. Usually, you can find this by looking at the sticker placed on your fitting, or in the lamp's specifications/instructions.

Caps and bases are labelled using both letters and numbers, with the letter indicating the type of base and the number indicating the diameter of the base in millimeters (mm). 

Here are some of the most common cap and base types:

Bayonet Cap


Edison Screw Cap


Small Edison Scew Cap


Spotlight Cap






  • ES/BC bulbs are commonly used in large household lights
  • SES bulbs are commonly used in smaller household lamps and lights
  • GU10’s are commonly used in spotlights and downlight fittings
  • G4/G9 bulbs are commonly used in smaller intricate light fittings

Where is the information I need to choose my bulb?

Bulb shapes.

Modern light bulbs come in a variety of sizes and shapes. Depending on your light fixture, you might have different requirements. For example, spotlights might need a spotlight shaped bulb (GU10/reflector), whereas pendant lights might use more decorative bulbs. Typically, there are 8 bulb shapes that one might find in use around their home.

Replacing old bulbs.

As the technology has progressed, the GLF bulbs have stopped being produced. Currently, it is more energy efficient to use LED bulbs. If you happen to need to change your bulbs but your old light fixture was using one of the GLF bulbs, don't worry, you can still replace these as long as you know your bulb cap.

Bulb technologies.

At ValueLights, we are all about saving you a little bit of money. Therefore, we only recommend using LED bulbs. Halogen bulbs are now a thing of the past and will no longer be available to purchase in the UK.


Light Emitting Diodes are the perfect replacement for your traditional halogen or incandescent bulbs. LEDs are known to use up to 90% less energy than older halogen bulbs and are known for being brighter and lasting longer.

LED Smart Bulbs

This type of bulb is relatively new. They are functional and can come in a variety of shapes and sizes. Some bulbs are able to colour change (RGB), whereas others are voice controlled or can be operated via a remote or smartphone app.

LED Filament Bulbs

The word Filament itself refers to the wire or thread inside the bulb which lights up when you turn it on. These types of bulbs are usually LED with a decorative wire inside.


The halogen light bulb or lamp was a type of incandescent light source which used a halogen gas in order to increase both light output and rated life. They were known to reach full brightness instantly, but had a shorter lifespan than LEDs.

Bulb ambience - know your Lumens.

Lumens are the measurement of light output/brightness. The more lumens in a light bulb, the brighter the light will be. 

In the past, to determine the bulbs brightness, we would use Watts, which is actually the power output measurement. Since the introduction of power saving bulbs like LEDs, the power needed to run a bulb doesn't match the brightness output. Therefore nowadays, bulbs need less power, but are a lot brighter, so we are now measuring the light output in Lumens.

  How many lumens do you need ?

Brightness 220+ 400+ 700+ 900+ 1300+
Incandescent 25w 40w 60w 75w 100w
LED Bulbs 4w 6w 10w 13w 18w

What are Kelvins? (AKA color temperature)

In addition to determining lumens on a brightness scale, you also want to figure out the colour of your light bulb. Generally, the higher the Degrees Kelvin, the whiter the colour temperature of the bulb. Although the whiter lights will appear “brighter” than those of a lower Kelvin reading, the number of lumens on the brightness scale does not change, and true brightness is not affected.

Low Kelvins generate warmer, cosier lights – perfect for your living room, dining room, bedroom and hallway.

High Kelvins give more energising neutral white light to create an energising, bright, vibrant and crisp environment – perfect for your kitchen, bathroom, study and workshop.

Warm white

Cool white

Beam angle.

All of our bulbs have a beam angle. In simple terms, this is the area that the bulb will illuminate. A standard light bulb will have a beam of about 360 degrees, and this means that the light emitting from it will surround the area, but will not be very intense. In comparison, the standard spotlight bulb or reflector will distribute light in a much smaller, precise area. Their angle is approximately 40 to 110 degrees.

To find out about the different lighting styles we offer, which feature these bulb types, view all our lights and find the perfect one for your home.