Remember the days when the light fittings in most UK houses took a 60 Watt bulb with a bayonet cap fitting?
Well, those days are long gone.
Since the ‘90’s, domestic light fittings and their respective bulbs have started appearing in an ever wider array of shapes, sizes, wattage's, fittings, technologies and voltages. Do you know your MR16 from your GU10? Would you recognise a G9 halogen capsule among a box of G4's? Is a 2.4W LED bulb a suitable replacement for a 50W halogen? Do you know the difference between an E14 and a SES fitting?
Okay, that last one was a trick question as an E14 is an SES fitting. My point is, you don’t have to hang around for too long in the lighting section of B&Q before you start hearing people getting confused about which bulb to buy for the new light fitting they’ve just bunged into their basket.
I find light bulbs to be an interesting topic which, conversely, probably makes me particularly uninteresting at parties. Nevertheless, here’s a bit of bulb-blurb to (ahem) illuminate the subject, and, hopefully clarify rather than confuse!
W A T T A G E / B R I G H T N E S S
The higher the wattage, the brighter the light. That’s the general rule so long as you’re comparing like-for-like lamps and not different technologies. For example, a halogen spotlight might come in 20W, 35W or 50W flavours, each being brighter than the last, however a 35W halogen spotlight bulb is actually brighter than a 40w filament spotlight bulb because it is a more energy efficient technology and gives off more light for the energy consumed. You will often see ‘equivalent’ ratings on bulb packaging, for example an energy saving 11-15W Compact Fluorescent Lamp (CFL) may be rated as an equivalent light output (lumens) to its traditional 60W filament counterpart. If you really want to compare different bulb technologies, look for the lumen rating as this will translate directly into the light given out rather than the power consumed.
T E C H N O L O G Y & E F F I C I E N C Y
On the domestic market, the range of technologies tends to be incandescent (filament) lamps, fluorescent/compact fluorescent/cathode lamps and Light Emitting Diode (LED) lamps.
When buying new lamps, it is wise to think of energy saving options. My original worklight used a 150W halogen lamp, however I decided to replace it with this 36W CFL version. Although it cost more to purchase, it runs cooler, consumes less energy and the bulb ought to require fewer replacements.
Incandescent lamps such as halogen rely on the burning of a filament in order to produce light. Of course, burning also produces heat which is an unwanted by-product as well as a waste of energy and potentially hazardous in certain situations. Halogen lamps provide more light with less power when compared to traditional filament lamps, however halogen lighting is often installed in multiples which makes them less efficient in practice. For example, a room may have had a single 60W ceiling rose replaced with four 50W halogen downlights, thus increasing the overall energy consumption by 333% to 200W. CFL or LED technology produces light with little waste heat so, in practice, those four halogen bulbs could be replaced by four compatible cool-running LED bulbs at 7W each, making a total load of just 28W with a similar light output. The LED bulbs would cost more to purchase, but quality LED lamps are rated for 10000 to 50000 hours instead of the 2000 hours of a filament/halogen version, therefore not only are they cheaper to run but they require replacing less often.
In fact, let's take a quick look at the maths. For the sake of making the sums easier, we'll assume one kilowatt hour (kWh) costs 10p and we'll look at a room that has 100 hours of lighting consumption over one month. Using the above example where four spotlights have been fitted in place of the original 60W ceiling rose, we can calculate the costs as below:
1kWh = £0.10 therefore the price per watt is £0.0001p
Single 60W ceiling rose x 1 hour = £0.006p/hour to run. Over 100 hours this would add up to £0.60
4x50W halogen lamps x 1 hour = £0.02p/hour to run. Over 100 hours this would add up to £2.00
Changing the four 50W halogens to 7W LED bulbs:
4x7W x 1 hour = £0.0028p per hour to run. Over 100 hours this would add up to £0.28
These calulcations are a little simplified and are based on one month of use for one room at a fixed rate. Start adding up your actual consumption at your actual kWh rate which may be over twice as expensive as this example, and scale it to years rather than months to see where your money is really going. Although the folks at the likes of EON and British Gas are probably very nice, I'm sure you'd prefer to keep as much of your cash in your own pocket as possible rather than dishing it out to them.
Traditional incandescent lamps are being phased out in favour of these newer technologies. This may mean you struggle to find a like-for-like replacement for the 100W filament bulb in your garage when it fails and you may want to consider switching to a more efficient fitting such as a 36W high-frequency fluorescent light. Fluorescent lamps require extra circuitry known as a ‘ballast’ in order to operate, and this is either included in the light fitting (as in the case of traditional striplights), or included within the bulb itself. CFL bulbs that are designed to be retrofitted into existing lampholders originally built for standard filament bulbs will have their own integral ballast. The inclusion of the ballast within the bulb often makes CFL lamps physically larger than their filament-burning counterparts, so if retrofitting new technology bulbs into existing housings, you may want to check they physically fit before buying in bulk.
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| A halogen GU10 spot bulb and its CFL equivalent. The ballast circuitry in this particular CFL lamp makes it larger than its halogen counterpart, so it won't actually fit into smaller spotlight housings. | Converters can be bought to quickly change one fitting type for another if desired. The one pictured above will change a B22d bayonet lampholder to an E27 screw without the need for any rewiring. |
F I T T I N G S
Off-the-shelf UK houses tend to come with a bayonet cap (B22d) ceiling rose in most rooms. A bayonet bulb has a pair of lugs which locate within the fitting and lock with a quarter turn. Two spring loaded pins push against contacts at the base of the lamp to ensure a good connection. The advantage of this fitting is that it doesn’t come loose which is why you often find it in high-vibration applications such as the rear lights on your car, however it is more complicated to manufacture with its spring loaded parts. Bayonet’s main rival is the Edison Screw (E27) fitting which tended to be more common outside the UK until the likes of Ikea invaded our shores. Ikea started selling standard lamps based on the E27 and E14 screw fittings - maybe that’s what they use in Sweden although the cynic in me thinks they probably figured as most UK households had a stash of spare bayonet bulbs, buying an incompatible fitting from Ikea meant they could also sell you the screw bulb to go with it. These days the E27 screw-cap fitting is a lot more common in the UK, and any non-ceiling lamp you buy from Homebase or Argos will more likely use E27 or it’s smaller sister E14 (aka. Small Edison Screw). An screw fitting is simpler to manufacture, however if the bulb is not screwed in securely it can work loose causing the bulb to flicker or appear to fail. If your screw lamp isn’t working, give the bulb a light clockwise twist to ensure it’s not just a bit loose before going to the trouble of replacing it. I've also seen the bottom or side contact in some screw lampholders lose 'springyness' over time which can make a poor contact if a new bulb is fitted that is a fraction of a millimetre shorter than the old lamp.
One pitfall is the naming of fittings; bayonet may be known as BC or B22d, E27 as ES and E14 as SES. I actually despair that the human race not only can’t standardise on types of fitting to reduce the variations in use, but that each one has different nomenclatures! Of course, other lamp technologies also have their own different fittings. A fluorescent fitting may require a T4, T5 or T8 tube, a halogen fitting might need a G4 or G9 capsule, an extra low voltage spotlight fitting would be built for either an MR11 or MR16 bulb, etc. There are many, many fittings, far more than I've listed here, and that’s why the bulb isle in B&Q has so many variants. If in doubt, take the old bulb with you when you need to buy a replacement.
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| Two types of fluorescent lamp, a T5 tube and a Biax L. Both require an external ballast to operate. The item at the bottom is both a ballast and a converter allowing a BC fitting to accept a fluorescent D lamp. | A traditional filament bulb alongside a CFL equivalent. The integral ballast circuitry makes this particular CFL much larger than the filament lamp so it may not be suitable for some fittings. At the top, an old minature CFL bulb has been opened exposing the ballast circuitry. |
D I M M E R S
In the ‘80’s, retrofitting dimmer switches was rather in vogue and allowed the light levels to be lowered when hosting the kind of parties that involved pineapple and cheese beng served on sticks and washed down with Babycham. Many modern energy efficient bulbs are not suited for use with these older dimmer switches as CFL and LED bulbs contain control circuitry designed to run from 230V and will fail to operate correctly if the voltage is dropped or pulsed. Similarly, replacing a single 60W fitting with multiple 50W halogen lamps will also cause problems with the dimmer switches of old as they may only be rated for sub-200W loads and are unsuitable for multiple lamps totalling more. Of course, there are modern dimming options, you just have to use the right bulbs and controls. If you require an energy efficient dimmer installation and you're not sure where to start, get in touch with me for a friendly chinwag.
R E C Y C L I N G
Fluorescent and CFL lamps contain mercury so should be disposed of at suitable waste recycling points. Warwick District Council provide such facilities at their waste handling sites such as my local at Princes Drive, however some retailers including Ikea also provide recycling services for used bulbs. If you break a fluorescent/CFL bulb, vent the room and place the broken bulb outside for a while to minimise inhaling mercury vapour, then carefully package it up and take it to your nearest handling facility.
C O L O U R, B E A M A N G L E & B A D P R E S S
There are certain aesthetic considerations to take into account if changing one bulb type for another. For example, although changing from 50W halogen bulbs to 7W energy efficient lamps will save the pennies, you may not like the resulting change in the way the room is now lit. Different lamps will also have different beam angles, lumen outputs and 'colour temperatures' depending on the make and model with some providing a warm yellow-white glow suited to living rooms and bedrooms while others may give out a cool, 'clean' blue-white light more at home in a modern kitchen or bathroom. CFL bulbs tend to have a warm-up time and don't reach full brightness for several seconds after switch-on. LED lamps, although instant-on, may suffer from mains flicker noticable in certain applications or conditions.
From my experience, although the initial change in the way a room is lit may take you slightly aback, it doesn't take long to get used to and become the accepted norm.
Technology is improving all the time and advances mean todays CFL lamps fire up quicker and produce a better light output than their older relatives while LED lamps are getting brighter and more effective. Both can be bought with varying colour temperatures these days, so you can choose a warm or cool colour to suit your tastes. The press like to carry the odd story denouncing change in anything, recent bans on inefficient bulbs being no exception, but some stories I've read having a crack at energy efficient lamps have been largely unwarranted and are nothing more than lazy journalists finding an excuse for some Brussels-bashing on a quiet news day.
B R A N D Q U A L I T Y
As with everything else, don’t be fooled by cheap imitations. LED technology is advancing quickly and as I write this in 2012, I predict it won’t be long until it’s the norm. LED lamps can be packaged smaller than CFL, last longer and provide the most energy efficient means of lighting. It is a case of buyer beware with LED lamps however. The best ones are the single-chip lamps that use one power-LED, or a bulb based on a small cluster of (usually three) power-LEDs. A high-brightness single power-LED bulb may consume only 4W with a tri-LED version consuming 7W, but the light output is strong and such bulbs are a direct replacement for filament spotlight equivalents. Beware of the sub-2W versions that use, say, 15-60 individual LED elements. These tend to be cheap, dim and are only suitable for accent lighting. Worse, from my experience, the LED’s in such bulbs are connected in series like the Christmas tree lights of old, and although each LED should last a theoretical 10000+ hours, cheap versions will use sub-par LED elements so when one fails after as little as a few months, the whole bulb is toast. A £3 mulit-element LED bulb stamped with a DIY store own brand or bought from China on eBay will be rubbish. A £15 power-LED bulb made by the likes of General Electric, Osram, Philips, Sylvania, Crompton or Ring represents better value for money in the long term as it will likely live up to its long life claims.
When choosing LED or CFL bulbs, make sure you get the same model of lamp throughout the room. Don't mix and match bulbs from different brands because there will be differences in colour, brightness and beam angle which will look odd. If you settle on a particular well-known make, then you should be able to shop around for the best price instead of relying on a single source such as a store own-brand that may go end of line before you've had a chance to buy all the units you need. You may also want to buy some 'sample' lamps to try them out in different rooms before settling on the technology that works best for you.
Two failed multi-LED GU10 bulbs. One has been broken open revealing the internal gubbins. These bulbs are unbranded and low quality parts were used in their manufacture. One or more of the individual LED elements has failed but, because they're all connected in series, a single failure causes the whole bulb to stop working. Had quality LEDs been used, these bulbs could have lasted at least 10000 hours. Instead, they've failed after a few hundred.
Not all applications are suitable for energy saving bulbs. This R39 spotlight bulb fits into my lava lamp which utilises the heat output of the bulb to melt the wax for the desired effect. A cool running CFL or LED bulb would not work in this particular application.
S P O T L I G H T S
Prior to the 1990’s, most ceiling spotlights used R63 or R50 screw-cap filament burning lamps which were pretty inefficient. By the ‘90’s, many new commercial installations had switched to MR16 extra-low voltage halogen lamps as they were smaller, more efficient and more attractive to look at. These small spotlights weren’t suitable for lighting large offices, but did look good in hotel lobbies, shop display lighting, bars and reception areas. By the late ‘90’s these MR16’s and their smaller MR11 sisters were starting to appear in the home in aftermarket installations. Both these types of bulb require 12V and are unsuitable for direct connection to 230V mains, so fittings either tended to come with an integral transformer to reduce the voltage or a transformer of the correct rating had to be sourced for the installation. Of course, this isn’t terribly ideal in the home and there was the potential for accidents to happen - people may use the wrong transformer for the job, they may try hooking 12V bulbs directly to 230V mains, the transformer may get installed in an unsuitable location where it becomes subject to moisture or overheating, etc. By the 2000’s, new spotlight bulbs were appearing based on the GU10 fitting. Although these GU10 lamps look similar to the MR16’s, they are rated at 230V and can run directly from the mains thus eliminating the transformer headache. These days you’ll still find both the extra low voltage and mains voltage fittings in the shops. Although the MR16 and GU10 bulbs look very similar in appearance, they are not pin-compatible so you can’t shove an MR16 lamp into a GU10 socket or vice versa. Both the low voltage and mains voltage fittings also come in a variety of wattage flavours, usually 20, 35 and 50 watt variants, so it’s important to choose lamps that match the rating of the fitting and, where applicable, the rating of the transformer. Incidentally, for those of you with the old R63/R50 fittings, energy saving CFL/LED bulbs can be purchased to quickly convert them into energy efficient spotlights. Reducing your energy bill doesn’t necessarily mean replacing your existing fittings to take advantage of newer, greener bulb technology!
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| GU10 and MR16 lamps look similar but the former requires 230V and the latter only 12V via a transformer. | Traditional spotlight fittings tended to be based on the R50 (SES) and R63 (ES) lamps before halogen spotlights became popular. Newer lamps are available for these older fittings and above are examples of CFL, tri-power LED and a single power-LED lamps. |
If considering halogen spotlight fittings, bear in mind these bulbs generate a lot of heat. The ceiling material needs to be able to withstand the localised increase in temperature and there must be enough airflow for the heat to dissipate. If halogen bulbs are often found failing in an existing installation, then it may be a sign of lamp overheating, especially if the bulb is angled and isn't able to spread heat evenly across its reflector. Different reflectors are also available with dichroic reflectors sending the heat backwards and aluminium reflectors throwing it forward with the light. Remember also that replacing a 36W striplight in your kitchen with six halogen spotlights may look more attractive, but you'll now be burning 250W on lighting and that will have an impact on your meter reading! LED or CFL bulbs are a quick and effective way to get around these heating and efficiency problems.
H A L O G E N C A P S U L E S
When fitting halogen capsules it is important not to touch the glass with your fingers as any grease or contamination on the glass can shorten its lifespan. Use a lint-free cloth to handle the bulb as you clip it into the holder. Halogen capsules also come in a range of sizes and can be low or extra low voltage depending on the fitting. As with spotlights, extra low voltage capsules will require a transformer.
A 12V 20W G4 halogen capsule
H Y B R I D B U L B S
It looks like a tungsten lamp and it burns a filament like a tungsten lamp, but look closely and you'll see this is a 230V halogen capsule shoehorned into a traditional GLS housing. The advantage is the lower wattage for brighter light that halogen can offer, the disadvantage is that it's still inefficient when compared to CFL or LED technology. Still, traditionalists and those with dimmer switches may prefer this innovation as a quick and dirty way to help reduce their lighting energy spend without losing the warm glow of filament burning technology. Known as a halogen GLS lamp, a 42W version should be about equivalent to a 60W lamp of old.
W H A T T H E R E G U L A T I O N S S A Y
Building Regulations Approved Document Part L (Conservation of Fuel and Power) has a few things to say about new lighting installations in the home. In domestic rewires, extensions or new buildings, Part L requires the installation of energy efficient luminaries, however simply installing bayonet fittings and inserting CFL or LED bulbs doesn't count as it shouldn't be possible for inefficient bulbs to be retrofitted. This means only fittings which are capable of specifically driving LED, CFL or fluorescent lamps (such as tube, biax or D style lamps) can be used. Don't panic however, we're not all about to get unattractive striplights shoehorned into our living rooms and bedrooms, Part L states an energy efficient light fitting must be installed per 25m2 of floor area (excluding garages), or one for every four fixed light fittings (whichever is greater). Such fittings should only accept lamps with a luminous efficacy exceeding 40 lumens per circuit watt (the energy consumption of both the lamp and any driver ballast/circuitry). This requirement would need to be taken into consideration in the event of major building/renovation work or rewiring, but sensible trade-offs are allowed so, for example, you could have a decorative but 'inefficient' ceiling light wired into your new extension so long as you installed an 'efficient' fitting elsewhere in the house, i.e. by installing something more energy friendly, if perhaps not so attractive, in the utility room.
T H E B O T T O M L I N E
Unless your a bit of a bulb-buff then reading this article may have left you more confused than ever about which lamp to lump for. These are the main points to remember...
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Buy branded long-life bulbs, not store own-brand or cheap knock-offs. Trusted brands cost more, but ought to live up to their long life claims whereas non-branded lamps may use substandard parts and fail much sooner than expected. Shop around for a particular brand and model to ensure you're getting the best price. | |
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Reputable manufacturers include General Electric (GE), Osram, Philips, Sylvania, Crompton and Ring. | |
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At the time of writing, LED bulbs below 3W are only suitable for 'accent' lighting. If replacing halogen lamps with LED, 3-7W power-LED lamps should be used to achieve comparable brightness. This may change as LED technology improves over the coming years. | |
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Multi-element LED bulbs are usually only suitable for 'accent' lighting and cheap versions have a higher chance of failure because the individual elements are connected in series and will all stop working if one element becomes faulty. | |
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Colour temperature should be considered, especially with LED lamps. A warmer yellow-white light around the 3000-3500K range is good for the living room or bedroom while a colder blue-white light around 4000-6000k may be preferred for kitchens and bathrooms. | |
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Mixing different makes/models of LED/CFL bulbs in the same room may look odd as dissimilar lamps will have differing colour temperatures, beam angles and physical appearance. Try to stick to one make/model in any given room. | |
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All lamps have their disadvantages. Tungsten/halogen lamps consume more energy and give off a lot of heat; Fluorescent/CFL lamps require some time to warm up to full brightness and LED lamps are expensive, often less bright and may have a narrower beam angle. That said, CFL and LED technology is moving quickly and these disadvantages are being reduced year-on-year. | |
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Changing the lamp technology in use will cast the room in a new light which may take some getting used to. | |
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The Building Regulations require energy efficiency to be taken into consideration for new builds and rewires. | |
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Upgrading to new energy efficient lighting doesn't necessarily mean changing existing fittings. For example, if you have old R63 spotlights, then you don't need to install the more common GU10 fittings to take advantage of LED spot lamps; such lamps can be sourced in the R63 form factor and retrofitted into your existing installation. |
If you want to discuss how you can upgrade the lighting in your home, whether you want updated fittings or to save money on the 'leccy bill by saving energy, please contact me to discuss further.
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