How to choose the perfect light bulb?

Interior Design

23 Oct

Have you ever wondered what all the jargon for light bulbs is about, all these letters and numbers being completely foreign to you? You wouldn’t be the first one to feel confused, staring at your screen or all the available options in the aisle, even interior designers past a certain point rely on lighting designers!

As much as the right light bulb is the essential finishing touch to any lamp fitting, choosing one can be daunting but the good news is, it doesn’t have to be! I have simplified everything below, so keep reading to make your next purchase less stressful.

The easy part, purely determined by the lamp fitting

There are a couple of parameters subject to the lamp fitting’s specification, so yes you will need to pay attention but ultimately won’t have to make a decision on them.

First, we have the light fitting and by that, we mean the way the bulb fits into the lamp. You will find this information online, on the lamp’s packaging and there is usually a little sticker on the lamp itself with this information. The three most common options are:

Screw bases, also known as “Edison” bases (E27 or E14 for the smaller version): as the name suggests, the bulb needs to be screwed / turned into the fitting
Bayonet bases (B22 or B15): these bulbs are placed into a socket using a push and twist action
Spotlight cap (GU10 and others): these bases have two-pins that need to be put into the available holes in the lamp and slightly turned to click into place. They are mainly used for recessed and surface spotlights.

The lamp fitting will also specify the correct wattage to use, by usually giving you the maximum number of Watts (W), Watts being the unit measuring the power consumption of the light bulb. Nowadays with the energy-saving bulbs, higher wattage doesn’t mean you’ll get a brighter light so make sure to not buy a light bulb consuming more than the limit, it might damage your lamp.

Parameters to decide on

Now that you have narrowed down your options of light bulb by following the manufacturer’s specifications, there are few other things for you to consider.

The type of lightbulb technology

Our parents were used to the old-fashioned filament bulb, but as most of their energy was converted into heat rather than light, they have been phased out and we now have more energy efficiency options:

CFL (Compact Fluorescent Lightbulbs): the white curly tube bulbs. They are affordable, available in a variety of sizes, are more energy efficient than incandescent bulbs and last for years but they are not necessarily the most aesthetically pleasing and the light they emit is not liked by everyone.
Halogen: they are rather bright and harsh, so are best for intense task lighting rather than indoor ambience, they can also emit a lot of heat and overall have a shorter lifespan and higher running costs compared to LED bulbs.
LED (Light-emitting Diode): they are the most energy-efficient type of lighting by far. They are also affordable, produce less heat, last for decades, give a lovely warm light and they look just as stylish as any Edison filament bulb. Oh, and dimmable LED bulbs are available.
Smart LED bulbs: if you want your home to be smart, you will need to invest in specific and technology compatible light bulbs such as smart LED bulbs. They will allow you to control multiple lights remotely through an app on your smartphone or with your voice via a smart home assistant.

The bulb shape

There are a lot of variations out there, from the small round bulb to the large version and the candle shape and you need to know that each of the different shapes provides a slightly different spread and angle of light, from the almost 360-degree spread of a globe bulb, to the narrow beam of a spotlight.

The shape of the bulb and spread of the light is ultimately down to your personal preference, but consider how the bulb will look when switched on as well as off, and whether it will fit well in the lamp. As a general rule, try to get a shape in proportion to the size of the lamp, ie large bulbs for large lamps and small ones for small lamps, you wouldn't want a large candle bulb sticking out from the top of your bedside lamp.

You will also find on the shelves clear and opaque light bulbs. Again, it comes down to personal preference, just bear in mind that with clear bulbs you will always see the filament and when switched on, depending on the brightness, it can sometimes be blinding if it’s a table lamp. On the other hand, opaque light bulbs provide a more glowy light.

The brightness

How much light do you need? Do you need a bright one for your desk? Or a softer one for your lounge?

Either way, what you need to look for is the Lumens, it is the unit used to measure the light output and therefore brightness of a light bulb. The higher the number of lumens, the brighter the light.

How many lumens you want from your bulb depends on the purpose of the light - is it for ambient or general lighting, accent lighting or task lighting such as reading, cooking, work or studying?
As a rough guide, for reading and writing, you should aim to get a light bulb with around 450 lumens (for a single lamp, like a bedside one). 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, it’s usually around 2000 lumens, but that’s where professionals can really make a difference, offering you plenty of flexibility for creating different ambiences when you use different light sources in combination.

The colour temperature

Maybe the most important thing to get right when buying a light bulb, this last parameter determines whether the bulb emits a yellow warm light or a cold blue one.

As the light’s colour has a direct impact on our mood, it’s important to get it right and stay away from a sterile, hospital feel. At the end of the day, you want to be able to do your daily tasks without straining your eyes but also relax.

The colour temperature of a light bulb is measured in Kelvins, abbreviated as “K” - low Kelvins generate warmer, cosier lights, and higher Kelvins colder bright colours.
I personally tend to specify light bulbs at 2700 to 3000K as it’s bright enough but has a soft, welcoming feel, it’s perfect for general lighting in the home. Some higher Kelvins can sometimes be useful in basements and garages, some people also favor them in the kitchen and bathroom but I wouldn’t recommend going above 4000K.

Whatever colour temperature you choose, make sure to stick to it throughout your space for cohesion and to avoid a patchwork effect.

A fun way to play with the colour temperature and the mood generated and it is by having a dimmer switch or even better a lighting panel which will enable you to create different lighting scenes - either way, make sure the light bulbs you buy are compatible with the technology.