How to choose a lightbulb: the complete guide

Large globe LED filament lightbulb glowing warm white in a glass pendant light

The right lightbulb is the essential finishing touch to a designer pendant or lamp. And as well as looking stylish, you’ll need the right amount of light for your purpose. Luckily we’ve made choosing the best lightbulb easy for you with this complete guide…

What light bulb do I need, in brief: for most lamps in sitting rooms and bedrooms, choose a warm white LED bulb (around 2700K) that gives enough light for the job (at least 450 lumens for reading), in a shape and size that suits your lamp, with the fitting your lamp takes (in the UK, usually B22 bayonet or E27 screw). Choose a pearl bulb when a shade hides it, and a clear filament bulb when the bulb is on show. 

Selecting a lightbulb sounds like it should be straightforward, but it can be rather confusing, what with fittings, wattage, lumens and energy efficiency to worry about. Not to mention shape, size and getting that stylish retro ‘filament’ look for a proper designer lightbulb. No wonder people feel like they need a little help. So with that in mind, here’s a complete guide. Below are quick tips for choosing a lightbulb for each of the main kinds of lamp: pendants, floor lamps, table lamps, wall lights and desk lights. But first, we explain the five key factors to take into account when choosing any bulb...

Large 6 watt LED filament lightbulb with a retro style filament

Stylish! A large 6 watt LED filament bulb - perfect when you want to complement a designer lamp

The five main decisions when choosing any lightbulb

1. How much light do I need?

The first thing to decide is how much light you’ll need from your lightbulb. These days everybody works in lumens, which is a measure of brightness. You can see how many lumens a bulb provides on its box, or, on our website in the information on each lightbulb page: 

Lightbulb product information showing the lumens rating

If, like most of us, you still think in terms of watts (a completely different kind of measure, which tells you how much energy is needed to produce light), then an old-fashioned 40-watt incandescent bulb gives about 470 lumens and an old 60-watt bulb gives around 800. (For LED lights the wattage involved is much lower to produce the same amount of light. For example, a 6 watt LED bulb can provide 450 lumens. That’s why lumens is a much better measure of brightness than watts.)

How many lumens you want from your bulb depends on the purpose of the lamp. For a lamp with a particular task you’ll want more lumens. For example, for a reading light you’ll probably want at least 450 lumens. Similarly, you’ll need brighter lights over kitchen worktops and in bathrooms, whereas in hallways fewer lumens will be fine.

For general ambient light where your lamp is one of multiple sources, it’s best to work out how many lumens you need in total for the room. A rule of thumb is that a sitting room or bedroom needs about 100 to 200 lumens per square metre in total and a bathroom or kitchen needs 750 to 850 lumens per square metre. So if your sitting room is 100 square foot just make sure your lightbulbs from ceiling lights, wall lights and lamps all add up to between 1,000 and 2,000 lumens. That way you’ll have plenty of light when everything is turned on, and plenty of flexibility for creating different ambiences when you use different light sources in combination. Our guide to layering light in the home shows how to combine them.

2. What type of lightbulb do I want? (hint: it’s an LED)

There are various different lightbulb technologies you may come across, all with differing qualities in terms of lifespan, energy efficiency and ambience. The four main kinds of lightbulb are:

  • Incandescent (aka standard, aka Edison) - the old-fashioned filament bulb we all grew up with. Lovely and bright, and brilliant in their time... but since some 95% of their energy is converted into heat rather than light and they have a short lifespan, they have long since been phased out of UK shops.
  • Halogen - about 30% more efficient than incandescent bulbs, but rather bright and harsh, and most were phased out of sale in the UK from 2021.
  • CFL (Compact Fluorescent Lightbulbs) - these are those white curly tube bulbs known for their eco-friendly credentials. Up to 75% more energy efficient than an incandescent bulb, but they’re pretty hopeless when it comes to creating a nice ambience, and they are, frankly, ugly. Most were phased out of UK sale from 2023.
  • LED (Light-emitting Diode) - the technology here has improved to the point where LEDs are now the bee’s knees. Not only are they the most efficient bulb (up to 80% more efficient than incandescent bulbs) and typically rated to last 15,000 hours or more, nowadays they can give a lovely warm light and they can look just as stylish as any Edison filament bulb. They’re very affordable now too.
Large globe LED filament lightbulb

Large globe LED filament bulb So the short answer to the question, ‘What kind of lightbulb do a want?’ is: ‘An LED one’.

3. What kind of ambience (‘colour’) do I want?

We’re now into the realms of personal taste. You can of course buy bulbs in different colours for decorative purposes, but even normal ‘white’ light has different ‘colours’. Slightly confusingly, this colour is measured in degrees Kelvin (K). And even more confusingly, the lower the ‘temperature’ the warmer the light. A candle is the ‘warmest’ light with a colour temperature of about 2,000K, while sunlight is 6,000K.

Here’s a chart:

Colour temperature chart showing warm white to daylight LED light from 2000K to 6500K

Image credit - Wikipedia Commons 

For most lamps in sitting rooms, bedrooms, dining rooms and so on, you’ll almost certainly prefer a colour temperature of around 2700K, known as ‘warm white’. That’s bright enough to be useful but also has a soft, welcoming ambience and is more flattering to the human face!  Higher temperatures (colder ''cool white' (around 4000K) and 'daylight' (5000K and above)  colours) can be useful in garages, utility rooms and home offices, and some people prefer them in bathrooms or kitchens. One more thing to consider on ambience: if your lamp is dimmable, make sure you get a dimmable LED bulb too.

4. What style of light bulb do I want?

These days you can choose from a range of LED lightbulb styles, to suit the look of your lamp. Shapes include: 

LED lightbulb shapes including large globe, GLS, golf ball and candle bulbs
  • Large format 'globe' LEDs: these look fantastic with a retro filament style
  • GLS (‘General Lighting Service’): the classic bulb shape
  • Golf ball: small round bulbs, great for certain pendant lights
  • Candle: the thin pointy ones.

But there are also lots of other stylish variations. In general, simply go for large bulbs for large lamps, and small ones for small lamps. In addition, you can choose between pearl (coloured white) LED bulbs and clear LED bulbs which show the filament. Again, it’s a matter of taste, but as a rule of thumb choose pearl bulbs for table lamps and floor lamps which take a shade, and use a clear bulb with pendants where the lightbulb is visible, so you can show off that lovely retro filament.

5. Which fitting do I need (bayonet or screw)?

Finally, there’s the fitting. This is the easiest decision because it’s entirely dependent on the requirements of your lamp - just make sure you check and get the right kind! 

B22 bayonet lightbulb fitting next to an E27 screw fitting

The two main types are bayonet (‘B’ fittings, above, left) and screw (‘E’ fittings, above right). The B system used to be predominant in the UK, but the more internationally-popular E is gradually taking over. The most common fittings are B22 and E27, and both are available in all sorts of shapes and sizes. Smaller lamps and wall lights often take a small E14 screw fitting, and some compact fittings use a G9 capsule bulb. The number is the width of the base in millimetres, so a B22 bulb won't fit an E27 lamp holder, and vice versa.


So those are the main factors to think about. And to help you even more, here are some quickfire, ‘rule of thumb’ guides for the different kinds of lamp..

What light bulb do I need for each type of lamp?

What kind of lightbulb do I need for a pendant light?

Quick answer: If the bulb is visible go for a clear LED with a filament, as they look the most stylish. In large single pendants you could go for a large round or GLS bulb (see above). For smaller pendants a golf-ball shape might be better. In sitting rooms, bedrooms, hallways and dining rooms choose a warm white bulb (about 2700K) and make sure the total light in the room from all your lights combined is around 100 to 200 lumens per square metre. You can go brighter in kitchens and bathrooms if you wish. Browse our pendant lights to find the right match.

Regular holophane pendant light in clear glass with a brass fitting


What kind of lightbulb do I need for a table lamp?

Quick answer: For table lamps with a shade a pearl LED bulb is fine in a GLS or candle shape, but go for warm white colour and if you need the table lamp for reading have at least 450 lumens. Check the maximum wattage on the lamp and the fitting it takes (usually B22, E27 or the smaller E14). 

What kind of lightbulb do I need for a floor lamp?

Quick answer: If the floor lamp’s shade covers the bulb, go for a pearl LED in a GLS or candle shape with warm white colour (around 2700k). If the bulb is visible go for a clear filament LED bulb in a GLS or candle shape. For a reading floor lamp, aim for at least 450 lumens; a floor lamp that's lighting a whole corner can take 800 lumens or more.

What kind of lightbulb do I need for a wall light?

Quick answer: Small lightbulbs, golf balls and candle shaped bulbs are ideal for wall lights. Go for a warm white light, and if the bulb is visible choose a clear LED light with the filament showing. If it’s not visible then a pearl LED bulb is fine. As with ceiling pendant lights, in sitting rooms, bedrooms, hallways and dining rooms make sure the total brightness in the room from all your lights adds up to around 100 to 200 lumens per square metre. Kitchens and bathrooms can be brighter if it suits your taste.

Roddy wall light in brass with clear glass rods

A wall light with the bulb on show, like the Roddy, suits a clear filament LED

What kind of lightbulb do I need for a desk light?

Quick answer: Desk lamps are task lights so you can go for a brighter LED, for example, 500 lumens, and choose either warm white or cool white colour. Most desk lights have hooded shades hiding the bulb, so any shape is fine, as is the matter of pearl versus clear filament.

What kind of lightbulb do rechargeable lamps need? 

Quick answer: Most Pooky rechargeable lamps don't take a bulb at all. They run on our Genesis cell, a warm white (2700K) LED light source and battery in one, which gives around 9 to 17 hours of light depending on brightness and recharges via USB-C. Browse our rechargeable table lamps, or read more about how long rechargeable lamps last.

It can be a confusing business, but we hope this guide helps you choose the right lightbulb for your lamp. You can browse all of our stylish LED lightbulbs here. And of course when you order a lamp from Pooky we’re very happy to recommend a bulb, just ask! Choosing a shade too? Our lampshade buying guide helps you find the right size and fitting.

FAQs about choosing a lightbulb 

How many lumens do I need? 

For a sitting room or bedroom, aim for around 100 to 200 lumens per square metre in total, adding up every light in the room. Kitchens and bathrooms need more, around 750 to 850 lumens per square metre. For a single reading or desk lamp, choose a bulb of at least 450 to 500 lumens. 

What is the difference between warm white and cool white? 

Warm white (around 2700K) gives a soft, slightly golden light that feels cosy and flattering, which is why it suits sitting rooms, bedrooms and dining rooms. Cool white (around 4000K) is crisper and more neutral, so it works for kitchens, bathrooms and workspaces. Daylight bulbs (5000K and above) are bluer still. 

Can I use an LED bulb in any lamp? 

In most cases, yes. Make sure the LED has the same fitting as your lamp (for example B22, E27 or E14), fits under the shade, and stays within the lamp's maximum wattage, which LEDs almost always do. If your lamp or light is on a dimmer, choose a dimmable LED. 

Do LED bulbs work with dimmer switches? 

Only dimmable LED bulbs work properly with dimmers, so check the packaging or product page. Older dimmer switches designed for incandescent bulbs can cause LEDs to flicker or buzz, so an LED-compatible dimmer switch is the safest choice. Our guide to light switches explains the options. 

How long do LED bulbs last? 

Most LED bulbs are rated for 15,000 hours or more, compared with around 1,000 hours for an old incandescent bulb. At a few hours a day, that's well over a decade of use.