Back when there were only incandescents, choosing a bulb was fairly simple – get the right fitting, shape and wattage and you were pretty much sorted, even if you did occasionally end up with a reflector bulb looking a bit odd in a lampshade.
However, since the advent of energy-saving bulbs, there seem to be any number of permutations, as manufacturers find ever new ways of bending fluorescent tubing into strange shapes. A lot of this is just slight variance between manufacturers though, as there are basically three main types of energy-saving bulb – sticks, spirals and ‘covered’ bulbs.
A stick bulb has a number of small, straight fluorescent tubes rising vertically from the base, and tends to be longer and narrower than a traditional bulb. A spiral bulb, meanwhile, has one continuous spiral tube that forms a round balloon shape like a traditional bulb (or a stylised ice cream cone!).
So is there any difference between these two types of bulb? To put it simply, not a huge amount. Spiral bulbs have more density of tubing, so they can give off somewhat more light than stick bulbs. Also, due to their more traditional outline, spirals can be better suited to traditional fittings where space is limited, or where you want to achieve a traditional ‘bulb’ look. Sticks, on the other hand, can make a real statement when used in modernist or minimalist light fittings, and are often better suited to long, narrow fittings, as they’ll provide light further along the length of the reflector or diffuser. In case you think these bulbs are only available as replacements for standard bulbs, however, you can also get them to suit golfball and candle fittings.
All of which brings us to covered bulbs, such as the GLS CFL bulb (GLS stands for ‘general lighting services’, i.e. the traditional bulb shape, while CFL stands for compact fluorescent lamp). This type of bulb looks much more like a traditional incandescent pearl bulb, with a single bulb shape rather than any visible tubes. As with spirals and sticks, these bulbs are also available in candle and golfball styles
A GLS CFL bulb works in exactly the same way as a stick or spiral, however, as underneath the translucent covering is a stick or spiral tube, just like one of those bulbs. Although it may look very tempting to get this type of bulb for tradition’s sake, there are a couple of reasons to choose a stick or spiral instead. Firstly, stick and spiral bulbs don’t have to squeeze into a cover, so have more length of tube, and hence give off more light. Nor do they have a diffusion layer, which again saps some of the brightness. GLS CFL bulbs tend to be somewhat pricier as well.
Basically, if your light fittings make the bulb visible, and you or the person you’re fitting them for is adamant about having traditional-looking bulbs, go for a covered bulb. Otherwise, for maximum light output at minimum cost, it’s worth choosing a spiral or stick.
Looking for more inspiration, news and advice? Try our Lighting Advice section.
Charles Barnett Managing Director
Charles started Lyco in 1995 with just 4 enthusiastic employees and has grown it considerably over the past 25 years. Charles is also the Managing Director of Lighting Direct and newly acquired Online Lighting. He now has a team of 50 lighting experts working on growing Lyco Group to be the UK leader in lighting for both businesses and homes. Away from the office he is a keen cyclist and is proud to have cycled 1017 miles from Lands End to John O’Groats to raise money for a new residential centre for adults with multiple learning difficulties.