Switching to energy-saving bulbs

Last updated Wednesday 14 October 2009

Low-energy bulbs - a bright idea?

An enduring symbol of energy efficiency, low-watt lighting offers more than a warm glow.

Compact fluorescent lamps (CFLs) use about 70% less electricity to produce the same light as a normal bulb, cutting greenhouse gas by over 50%. A hard-working bulb could save you 7 a year. Across the whole home you could save as much as 45 each year.

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Photo: Switching to energy-saving bulbs

Saves up to 155kg per house or 16kg per bulb of CO2 each year

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CO2 reduction 1 out of 5

Cheapness 2 out of 5

Popularity 5 out of 5

Cost 5 - 50

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What difference will it make?

Pub Fact

  • Over 50 million energy-saving bulbs are being used today in the UK - only 10% of the total light bulbs in use
  • UK usage of lighting generates about 350kg of CO2 per year per household, or 150kg CO2 per person
  • A typical house has 25 light fittings
  • There are 600m light sockets in the UK
  • If everyone in the UK installed three energy-saving light bulbs, we would save enough energy to power all the UK's street lighting for a year
  • Old thermometers contain about 500 milligrams of mercury - equivalent to the amount contained in 100 CFLs
  • There are 1.6 billion people in the world with no access to electricity at all
  • If every house in Britain replaced at least one of their incandescent bulbs with an energy-saving lightbulb, it would prevent the release of greenhouse gases equivalent to the annual emissions of 800,000 cars, according to the International Energy Agency
  • 81% of people say they have at least one low-energy light bulb at home compared to just over 30% a few years ago
  • Global lighting creates an amount of greenhouse gas equivalent to 70% of the emissions produced by light passenger vehicles the world over

Low-energy bulbs need about 70% less energy than traditional ones, reducing average annual electricity consumption for lighting from 700kWh to about 150kWh. This benefits the planet and your pocket alike:

  • If everyone in the UK installed one bulb, we'd save enough CO2 to fill the Albert Hall nearly 1,200 times
  • The low-energy light bulb and other efficient lighting systems could prevent a cumulative total of 16 billion tonnes of carbon from being added to the world's atmosphere over the next 25 years, according to the International Energy Agency
  • A house with 25 bulbs - about the average - could save 45 a year in electricity bills. Bear in mind that we spend 1.8bn on lighting UK homes each year - enough to pay for 47,000 new nurses and 45,000 new teachers
  • Low-energy bulbs are also recyclable, unlike traditional incandescents

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How do I do it?

  • Survey the market-place to find your ideal bulb, courtesy of the Energy Saving Trust
  • Check the wattage on the light you are replacing and purchase a CFL with the equivalent, lower wattage. As a rule of thumb, CFLs use about a fifth of the wattage to produce the same light. So to replace a traditional 60-Watt bulb, look for a CFL that's about 11 Watts
  • Check the lumen rating on the light you are replacing and purchase a compact fluorescent light bulb with the same lumen rating. (A lumen rating is the measure of light the bulb puts out)
  • Buy an 'energy saving recommended' bulb with a colour temperature of about 2,700K and a colour rendition index (CRI) of at least 80 (high CRI makes colours look natural and vibrant)
  • Planning on putting a CFL outside? Ensure that you purchase one rated for outdoor use, or wet applications
  • Dimmable CFLs are available from some outlets at a higher price
  • When the energy saver eventually dies of old age, recycle it at the local recycling bank

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What's stopping me?

"Are they safe? I've heard they're full of mercury and that they might give me headaches"

Energy-saving bulbs do contain mercury, but in such small quantities they represent no significant health hazard, according to BBC News. Despite a small number of anecdotal reports about health concerns for migraine and epilepsy sufferers, the Department for Environment Food and Rural Affairs (Defra) has provided assurances that the new 'Energy Saving Recommended' bulbs are not a danger to the public.

"Five quid a pop! They're a bit pricey"

But they go 'pop' a lot less often. They last long enough to be cheaper than a conventional bulb, even before you factor in the electricity saved.

""Won't efficient bulbs make my house colder?"

Traditional incandescent bulbs are so inefficient they give off 95% of their energy in heat. This doesn't make them a good substitute for central heating. Insulation's a better way to keep warm without burning too much electricity.

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What's the debate?

CFLs are criticised for containing the dangerous neurotoxin mercury. But at 4mg a pop, you'd be hard-pressed to lose your sanity. In fact, CFLs emit nowhere near as much mercury as conventional bulbs, says Defra. If you're worried about mercury, its best to look at electricity generation by power plants, which are the largest source of mercury in the atmosphere. Because CFLs are more energy efficient than incandescents, they save on the amount of electricity that needs to be generated to light your home.

Critics point out that the embodied of CFLs are higher than those of traditional bulbs. With ten times the lifespan of ordinary bulbs, the energy they save far outweighs that used in manufacture. So they still outshine their rivals' green credentials.

Detractors claim there's no evidence that energy-savers are actually reducing energy demand in the UK. However this is due to higher numbers and wattages of other light bulbs in our houses rather than inflated claims of CFLs' energy efficiency. 140m a year is also wasted by leaving lights on unnecessarily.

Health charities warn that the switch to energy-saving light bulbs may put Brits with photosensitive skin conditions at risk of skin reactions. If you fit this bill, consider buying LED Lighbulbs instead.

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Comments

Baz, Shrewsbury 2009-01-08

Around 4 years ago an EU ruling compelled all businesses to dispose of most lamps, including flourescent types in an environmentally considerate manner. This obligation now extends to Joe Public (us!). Yes I know we will all dispose of our old CFL's correctly, but somewhere on this planet there must be an awful big plile of busted CFL's.
This will of course be called an authorised dangerous waste site, but it is till here with us and it is a huge depository of the waste products such as mercury from the lamps and other chemicals from the electronics of the lamp control gear.
So, CFL's are not the panacea they are made out to be.

Baz, Shrewsbury 2009-01-08

Dear Breadon, Pershore,
It's true, your flicker problem could be capacitive linking caused by the three core and CPC cable run in the two way switch. I have seen this problem on ordinary linear flourescent lamps, turn 'em off and in the dark they still glow a bit. other options to consider could be an unusually high neutral to earth voltage or a reversed polarity in your lighting circuit, although your electrician should have checked for this in the pre commissioning tests outlined in the Electrical Regulations.
I suggest that if no fault is found, change the 2-D fittings for ones with electronic rather than inductive ballasts.

Baz, Shrewsbury Shropshire 2009-01-08

Shrewsbury Shropshire
90% of my lamps are CFL.s including the outside lights. I know they save me around 75% on my lighting costs.
I would advise of the possible pitfalls
Make sure you install 10% more light than you need as the light output falls off with age, also the light output will not reach maximum until they are at running temperature.
Only use CFL's or other flourescents that have electronic control gear, not a heavy wound choke (inductor)
Flicker from these lamps should not be an issue when they are new as the frequency at which they operate is around 20,000 Hz, however, as they age the smoothing capacitor in the power supply of the lamp circuit looses its capacity and the 50Hz mains flicler may become apparent to some more sensitive people. The solution is to change the lamp OR run them off 240V DIRECT CURRENT from a battery supply charged by your wind turbine perhaps.

Anonymous 2009-01-07

Three years ago I surveyed my house (4 bed Cotswold cottage) and found an astonishing 101 bulbs. This included outside lights, fridge. cooker hoods etc.
Guess how many were the famous 100w bayonet bulb?
Answer :1
The electricity board sent me an eco-replacement. It was an inch longer and did not fit the outside lamp holder.
I struggle all the time to find low energy equivalents, and am aware that almost 50% of my bulbs require an expensive change to the fitting and transformer.
Replacing the 100w bayonet is a good start, but people need to acknowledge that it is no-where near the answer.

Anonymous 2009-01-07

Three years ago I surveyed my house (4 bed Cotswold cottage) and found an astonishing 101 bulbs. This included outside lights, fridge. cooker hoods etc.
Guess how many were the famous 100w bayonet bulb?
Answer :1
The electricity board sent me an eco-replacement. It was an inch longer and did not fit the outside lamp holder.
I struggle all the time to find low energy equivalents, and am aware that almost 50% of my bulbs require an expensive change to the fitting and transformer.
Replacing the 100w bayonet is a good start, but people need to acknowledge that it is no-where near the answer.

Breadon, Pershore 2008-10-16

We have replaced some of our light bulbs BUT some of our light fittings are incompatible. We replaced the (incompatible) light fittings on hall, stairs and landing with ones that take the D shaped CFLs. The circuit controlled by three-way switching has a problem. The new bulbs flicker when turned OFF. We had the electrician back but he was defeated by the problem. According to the IETs Engineering & Technology Mag (6 -19 Sept 2008) this is probably due to 'slight capacitive leakage between cores of the 3-way-and-earth 2-way switch cable'. (Fitting on two way switched circuit does not flicker.) Am bit reluctant to try the solution suggested in reference as I am not an electrician.

chinago, china 2008-08-28

now global climate change is big problem.we live in the same global_village,do our best and change bad living habit to help our blue global,.i have switched all my energy saving bulbs

The Bloom Team, London 2008-08-19

Dick, your concerns are valid to a point. While it's true that you will lose some heat by switching to more efficient lighting, this is taken into account in the savings discussed above.

Lighting is not an effective or efficient way of heating your home: grid electricity is almost 3 times more carbon-intensive and 4 times more expensive than gas.

It is therefore much better for both the climate (and your wallet) to go for efficient lighting and make your boiler work a little bit harder.

Read more about the Heat Replacement Effect on the EST's website: http://www.energysavingtrust.org.uk/energy_saving_assumptions

And check out the Market Transformation Programme's website:
http://www.mtprog.com/spm/download/document/id/579

All the best, the Bloom Team

DavidfromNorfolk 2008-08-14

Dick whilst I agree with you up to a point, in the coldest days of the year. We have fully insulated our bungalow and for most of the time do not rely upon our heating system to keep us warm as passive heating from the sun is sufficient for us.
We have converted every bulb in our home to CFL's, but will be looking forward to changing these to LED's as their design improves and our CFL's need replacing.

Dick Daniel, Brig o' Weir 2008-06-25

The general public are being hoodwinked over this issue of energy saving light bulbs. In the UK, we are mostly concerned with keeping our homes/offices/shops/factories etc. at a comfortable temperature ABOVE ambient. This requires HEAT. Incandescent light bulbs give off heat, which helps keep our premises above ambient. Replacing with low energy light bulbs merely means that our heating systems have to supply the energy "SAVED". Since these systems are not 100% efficient, they use more energy to compensate for the energy "SAVED", so the savings are in fact negative. The gas industry is being less than truthful in offering free energy saving light bulbs to users, since adoption will in fact INCREASE the energy required from THEM. Why do the EU governments not consult real experts to advise the best way forward, rather than manufacturers with vested interests? It's time this fiasco was STOPPED....

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Glossary terms used on this page
CFL bulbs
CFLs are compact fluorescent lamps. They operate on the same principle as fluorescent lights but the tube is folded into a more compact design so they are more versatile and can be used in devices designed to take traditional incandescent bulbs. They use about 80% less electricity than traditional bulbs to produce the same light and last considerably longer. Their mercury content means disposal, especially of broken bulbs, requires extra care. Also referred to as low-energy lightbulbs.
CO2
CO2, or carbon dioxide, is made up of the elements carbon and oxygen. It exists quite naturally in our atmosphere, as part of the carbon cycle. Everyday processes in the plant and animal world both add CO2 to the atmosphere and take it out. However, because it is a greenhouse gas - meaning it affects the temperature of the earth - the exact level of CO2 is important. Burning fossil fuels releases CO2 into the atmosphere, hence the anxiety that extensive use of these fuels is causing climate change.
CO2
CO2, or carbon dioxide, is made up of the elements carbon and oxygen. It exists quite naturally in our atmosphere, as part of the carbon cycle. Everyday processes in the plant and animal world both add CO2 to the atmosphere and take it out. However, because it is a greenhouse gas - meaning it affects the temperature of the earth - the exact level of CO2 is important. Burning fossil fuels releases CO2 into the atmosphere, hence the anxiety that extensive use of these fuels is causing climate change.
Carbon
Carbon is the fourth most common chemical element in the universe, and carbon compounds - in other words, carbon chemically combined with other elements - are the basis of all known life forms on earth. Pure carbon appears in many apparently diverse forms, from diamond to graphite to charcoal, but it is much more commonly found in substances such as coal, oil, natural gas, wood and peat that we use for fuel. When we burn these substances to provide energy - either directly in our homes as heat, or in power stations to produce electricity - the combustion process produces 'oxides' of carbon, including the gas CO2.
Embodied energy
Embodied energy - sometimes referred to as 'embedded energy' - is the energy used (and therefore the CO2 emissions) in manufacturing, packaging and transporting a product, material or service. So when calculating the CO2 savings from a new energy-efficient product such as a boiler or washing machine, its embodied energy needs to be taken into account. Usually the energy saved in use will quickly compensate for the embodied energy, but in some cases - such as small urban wind turbines - it may be that a product will use more energy in its manufacture than it will save across its lifetime.
Energy efficient
definition to follow
Fluorescent lights
A fluorescent bulb or tube uses the flow of electricity to excite mercury vapour in an inert gas (argon or neon), which creates invisible ultraviolet light. A coating of phosphor on the inside of the glass then converts this into visible light - a process known as fluorescence. They have higher energy efficiency and longer life than traditional incandescent bulbs. See also CFLs/low-energy lightbulbs.
Greenhouse gases
Greenhouse gases raise the earth's temperature through the greenhouse effect. There are six main examples. As well as carbon dioxide, they include: water vapour, methane, nitrous oxide, ozone and CFCs (which include sulphur hexafluoride, HFCs, and PFCs). Of these, carbon dioxide, methane, nitrous oxide, sulphur hexafluoride, HFCs, and PFCs are controlled under the Kyoto Protocol to limit their concentration in the atmosphere. The heat warming capacity of each gas is measured by its 'global warming potential': how much heat it traps depends on its chemical make-up and how long it stays in the atmosphere.
Incandescent bulbs
Incandescents are traditional lightbulbs that use a filament (a thin thread of metal, usually tungsten wire) inside a glass bulb that glows white hot as electricity passes through it. The filament is prevented from burning either by creating a vacuum inside the bulb or filling it with inert gas. They are far less energy efficient than fluorescents/CFLs or LEDs because most of their radiation is given off as heat rather than visible light.
Kilowatt-hours (kWh)
A kilowatt-hour is an amount of energy equivalent to a power of one kilowatt (a thousand watts) running for one hour. The unit is commonly used on electricity meters. If you know how many kilowatt-hours of energy your household uses, you can translate this into kilograms of CO2 emitted by multiplying it by 0.527. A megawatt hour (MWh) is an amount of energy equivalent to the power of one megawatt (a million watts) running for one hour. Similarly, a gigawatt hour (GWh) is a billion watts for one hour, and a terawatt hour (TWh) is a trillion. While your domestic gas bill will be set out in kWh, the output for a power station, for example, will obviously be expressed in one of these much larger units.
Mercury
Mercury (chemical symbol Hg) is a metal that is liquid at standard temperature and pressure. It is used in the manufacture of low-energy lightbulbs (CFLs and other fluorescent lights), and extra care must be taken in their disposal, especially when they are broken, because of mercury's toxicity.
Toxins
A toxin is a chemical compound from one organism that is harmful to another organism.
Watt
A watt is a unit of power. Power is the rate at which energy is used, and a watt is equal to a rate of one joule of energy per second. Watts are commonly used when referring to the energy consumption of relatively small things like lightbulbs, while kilowatts (a thousand watts) are used for larger machines. Megawatts (a million watts) are used to measure the electricity generation of power stations. See also kilowatt-hours.

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