Now LED bulbs are finally getting there. A couple of years ago they would cost you an arm and a leg if you change all your bulbs at home (an average house in Britain has ~25 bulbs) into LED ones but now you can get a pretty decent one for a few quids. This is when their electricity bill cutting starts to make sense as you can get the upfront cost back roughly within half a year. All the left in their claimed 10+ years lifetime would then be pure savings. It can however be quite a headache when it comes to choosing an LED bulb (yes, if you search “LED bulb” on Amazon you get seven hundred thousand plus results). Well, they all say that they are super energy efficient, offer brilliant light and last for almost forever, which is simply not the case. Although there is loads of information on the web trying to advise how to make that choice, when you start to get into the detailed specs, jargons like the CCT and CRI do not always make a lot of sense. Even when you think you have figured out all the tricks and finally installed a batch for your living room, it is not unusual to “just not feel the same as before”. What I will be discussing here is an approach to choose an LED bulb simply by its appearance, without having to work out the specs. It’s not going to be as precise as digging into the datasheet but it probably takes 1% of the time needed and filter out 99% of those not worth spending time on. Also I will not be covering things like the base or shape of the lamp, e.g. E27 or E14 or GU10, since there is already plenty out there. A somewhat popular type of LED bulb that you should definitely not touch is those consisting of lots of small “lamps” such as These small “lamps” are LEDs of the last century. They are simply neither bright nor efficient enough. More commonly seen are bulbs with bare yellow chips exposed without any lens or diffuser (normally translucent plastic that spreads out the light) on them, such as Stay away from this type because it can’t deliver the light to where a proper bulb should do, and it tends to glare badly – the bulb shines too brightly but does not illuminate properly, if that makes sense. More importantly, these useful optical components are omitted mainly due to cost saving. Therefore the other parts used in such a bulb would unlikely be of high quality. You may end up with a third of the chips still working after a couple of weeks, or the whole thing just fails as the driver can’t cope with its working conditions. Taking this approach forward, it is fairly safe to judge the quality of an LED bulb by the complexity of its optical components, i.e. lenses and diffusers, which are the most visible. Normally a bulb with a thin and flat layer of diffuser as its only optical component tends to be cheap, and claims such as long lifetime on such LED bulbs would be very doubtful. A high quality LED bulb tends to have a large and robust piece of diffuser with a sophisticated shape, or in the case of directional lighting such as PAR lamps including GU10, a lens designed with a certain level of complexity. Here are some examples from Philips The diffuser and the lens direct and distribute the light to where it should go to optimize the illumination and minimize the glare. More importantly, as they are indeed a less essential part of the lamp (or of the datasheet), if the manufacturer decides to spend substantially on them they are more unlikely to compromise the quality on the more critical parts such as the LEDs and the driver. The most complex lens design is perhaps a “3D lens”, which enables smart distribution of the light within a limited space, making the bulb compatible for more luminaires. Here are some flagship products from Philips and Osram, the world’s top two lighting suppliers. It is not surprising that products with sophisticated diffuser or lens tend to be more expensive. Here are a few on Amazon with 3D lenses http://www.amazon.co.uk/Osram-LED-T...1458150908&sr=1-6&keywords=LED+STAR+CLASSIC+P http://www.amazon.co.uk/Philips-453...sr=1-1&keywords=MASTER+LEDcandle+DiamondSpark http://www.amazon.co.uk/SUNVESA-Edi...e=UTF8&qid=1458152019&sr=1-1&keywords=sunvesa http://www.amazon.co.uk/Light-Bulbs...51742&sr=1-255-spons&keywords=led+bulbs&psc=1 Again, judging the quality of an LED bulb by the complexity of its optics is quite opportunistic and may not be accurate. But the approach is probably an optimal tradeoff between the time you want to spend in choosing a bulb and the risk of not getting your place lit up properly. After all, LEDs are the light source of this century.