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Spotlight on… light bulbs

Image of the bedroom of @houseofbeau13

Spotlight on… light bulbs

Buying the right light bulbs can feel overwhelming, can’t it? There’s so much information – watts and lumens, bayonet fitting or Edison screw – that choosing the right bulb can seem like a shot in the dark.

Lighting designer and electrician Eleanor Bell has answered some common questions to help you find the right bulbs for your home – whether you’re changing existing bulbs to create a different effect or simply replacing bulbs that have blown.

Image: Lighting designer, light artist and electrician Eleanor Bell.
Halogen, incandescent, fluorescent or LED?

In one fundamental way, buying light bulbs has got easier. There was a time when you had to choose between LED, halogen, incandescent or fluorescent bulbs. The good news is that currently, both halogen and incandescent bulbs have already been phased out (although retailers can still sell existing stock), and fluorescent ones are predominantly used in commercial settings, which just leaves LED.

Can I just swap my existing bulbs for LED bulbs?

In many cases, yes – you can remove your current light bulbs and replace them with LEDs. However, it’s a bit trickier if you have dimmer switches because not all LED bulbs are designed to be dimmed. Check the bulb packaging to make sure you’re choosing LED bulbs that can be dimmed.

You could also find that your dimmer switch isn’t compatible with dimmable LED bulbs, as it is designed to dim halogen and incandescent bulbs, which use a different technology to LEDs. You’ll know this is the case if your LEDs start to flicker or make a buzzing noise. If this happens, you’ll need to call an electrician to update your dimmer switch.

Do I need to know my cap fitting?

Yes – the first step to buying a new light bulb is to identify the shape of the cap (the metal bit at the bottom that fits into the lamp holder). For example, is it an Edison screw or bayonet cap, and what size is it: standard or small? Why not take the light bulb you’re replacing with you so that you can easily find the fitting you need?

Watts or lumens – what’s the difference?

Traditionally, light bulb brightness was measured in watts (W), which is a unit of energy consumption. However, LEDs are measured in lumens (shown as lm), which is the light output. As a rough guide, when comparing the wattages of the old incandescent bulbs they have the following lumen output. A 100W bulb has the brightness equivalent to 1500lm, 60W is approximately 800lm, 40W is approximately 450lm and 25W is approximately 250lm. Put simply, the higher the number of lumens, the brighter the light will be.

Don’t worry about having to convert numbers in your head – you’ll find the lumens output, the equivalent wattage and the bulb’s energy consumption on the packaging.

What brightness do I need?

How many lumens you need depends on the purpose of the lightbulb. As a general rule of thumb:

Pendant: 800 lumens
Table lamp: 450 lumens
Downlight: 350-500 lumens
Floor light: 450 lumens

What is colour temperature?

In addition to checking lumens, you’ll also need to take colour temperature into account. This refers to how cool or warm the light is. Bulbs range from a yellow, warm white through to a much brighter, cleaner white, which is often used in hospitals, schools or other commercial settings because it keeps people more alert.

Kelvins (K) are the measure of how cool or warm a light is; the higher the number of Kelvins, the whiter the light. You’ll find this information on the packaging.

What colour temperature do I need at home?

We tend to switch on lights in the evening when we want to create a relaxed atmosphere to prepare our bodies for bedtime, so think warmer tones. It comes down to personal preference, but I recommend 3000K in the kitchen where you need the space to be a slightly crisper white light and 2700K in rooms where you relax. Stick to the same colour temperature for all light bulbs in the same room: if you start to chop and change, you’ll draw attention to the lighting, which is precisely what you want to avoid. Instead, aim to direct the eye to what’s being lit and not the light bulb (unless you’ve specifically chosen a designer one). 

Of course, there are exceptions to wanting a warm and relaxing light. For example, if you do needlework or artwork and you need to see the true colours, I’d recommend a daylight bulb that’s 6000K. Avoid a very yellow light bulb in this situation, as it’ll change the hue of the colours.

If your lights are on a dimmer switch, you can tailor your lighting to what you’re doing. This is great for multifunctional spaces. Look for dim-to-warm LEDs that start at 3000K at full brightness but dim to 2200K. The beauty of these is that as they get dimmer, they get warmer, which is exactly what halogen bulbs used to do.

What do I need to know about beam angles?

For a wash of general lighting – for instance, overhead lights in your kitchen – you’ll want a standard beam angle (generally 35 to 45 degrees) which will give you a good spread of light across the whole floor. If you’re trying to create a feature by highlighting a particular area or object, you’ll want a narrow beam angle, for example 10 or 15 degrees. You’ll find this information on the packaging.

Are smart light bulbs different from standard light bulbs?

Smart bulbs (for example, below left) can be controlled wirelessly via an app, a remote control or a wireless light switch using WiFi, Bluetooth or another technology, for example Zigbee. Philips Hue is an example of a smart lighting system. In terms of the cap fitting, brightness and colour temperature you can apply the same considerations as standard bulbs.

About Eleanor Bell Studio: Eleanor Bell Studio is an architectural lighting design practice and bespoke lighting fabrication studio based in Penryn near Falmouth in Cornwall. The studio was founded in 2007 by lighting designer, light artist and electrician Eleanor Bell.

Featured image: The beautiful bedroom belongs to Carla of @houseofbeau13.

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