19 FAQs and answers about A-rated energy saving bulbs.

1. Is it true that you need to use more heat in the house if you switch to energy saving bulbs?
2. Are the environmental benefits of energy saving bulbs outweighed by the negative impact of the mercury in the bulbs?
3. Does it take more energy to produce an A-rated bulb than an incandescent?
4. What is the difference between A-rated and B-rated bulbs? And why does the Trust only recommend the A-rated ones?
5. Can I be sure that bulbs on the Trust’s list will last as long as is stated by the producer?
6. Can I replace all my incandescent bulbs with A-rated equivalents?
7. Where can I buy bulbs on the recommended list of A-rated bulbs?
8. Is the light quality as good when fitting an A-rated bulb?
9. What is the technical difference between an A-rated bulb and an incandescent?
10. In terms of fire hazard, how safe are A-rated bulbs?
11. What are C-rated and E-rated bulbs?
12. Why do A-rated bulbs not always fit my lamp sockets?
13. Does price have a bearing on whether an energy saving bulb can be categorised as being A-rated?
14. How can I be sure that the energy saving bulbs on the recommended list of A-rated bulbs will live up to the quality requirements that have been established?
15. Why does the Trust recommend that you replace 60 watt incandescent bulbs with 15 watt A-rated bulbs, when some producers write on the packaging that 60 watts is the equivalent of 11 watts?
16. Can A-rated energy saving bulbs cause stress, concentration difficulties and depression?
17. Can I get A-rated energy saving bulbs which work in lamps with dimmers?
18. Can A-rated energy saving bulbs cause migraine and epilepsy?  
19. Is it true that it doesn't pay to switch off an A-rated bulb?

1. Is it true that you need to use more heat in the house if you switch to energy saving bulbs?
It’s true that energy saving bulbs give off less heat than conventional bulbs and therefore contribute less to the heat level in the house than tungsten filament bulbs. However, the difference is very small because:

• Some of the lamps hang in the ceiling, where the heat from conventional bulbs cannot be used anyway because the heat is dissipated upwards.
• If you don’t have electric heating* the heat is significantly cheaper, often by as much as 30-40%, than the electricity from tungsten filament bulbs for example.
• Many bulbs are in rooms that do not require heating – for example, the basement, garages and patios.
• It’s only during the heating season that you can utilise the warmth from conventional bulbs. During the summer this emitted heat can actually be a disadvantage because, for many people, it can lead to higher electricity consumption in the form of increased ventilation and cooling.

The Trust therefore reckons that you will save EUR 53-67 for each tungsten filament bulb you replace with an A-rated energy saving bulb. This figure takes account of the slightly increased consumption of heat entailed in switching to A-rated bulbs.

* If you have electric heating, the savings by having A-rated bulbs are considerably less; this is because the lost heat from the tungsten filament bulbs needs to be replaced by electric heating which is expensive. As yet, no research has been undertaken to show exactly how much less the saving is in these circumstances, but the Trust estimates it to be 50%.
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2. Are the environmental benefits of energy saving bulbs outweighed by the negative impact of the mercury in the bulbs?
Energy saving bulbs contain mercury, which tungsten filament bulbs do not; but mercury is also discharged into the environment during the production of electricity. To a large extent, Denmark uses coal to generate electricity, and burning coal leads to the discharge of mercury into the atmosphere, even if the smoke is cleaned.

All in all, less mercury is therefore discharged when we use energy saving bulbs because they use so little electricity. Also, many energy saving bulbs are taken to waste recycling centres where the mercury is processed in an environmentally correct way.

In all cases, choose an A-rated bulb containing the least mercury. You will often find the mercury content on the bulb’s packaging.
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3. Does it take more energy to produce an A-rated bulb than an incandescent?
Yes, but because an A-rated bulb has a longer lifetime it takes less energy to produce these bulbs if A-rated bulbs are used instead of incandescents.

• Incandescent bulb: Energy used in production = circa 0.29 kWh
• A-rated bulb: Energy used in production = circa 1.7 kWh

However, note that A-rated bulbs have a lifetime that is at least 6 times longer than conventional bulbs. So, when you multiply the energy used for producing an incandescent by 6, the result (namely 1.74 kWh) is a little higher than the figure for an A-rated bulb. Therefore, in energy terms, it is cheaper to produce A-rated bulbs in the long run.

Source: ‘Electric light sources’ published by Denmark’s ‘Lysteknisk Selskab’ in 1993. Back to top

4. What is the difference between A-rated and B-rated bulbs? And why does the Trust only recommend the A-rated ones?
Both A-rated and B-rated bulbs are energy saving bulbs, but A-rated bulbs use the least energy, which is why the Trust recommends them.
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5. Can I be sure that bulbs on the Trust’s list will last as long as is stated by the producer?
A-rated bulbs on the list will tolerate being switched on and off for at least the same number of times as the bulb’s life expressed in hours. Random tests ensure that the requirements are fulfilled.

For example, a recommended energy saving bulb with a lifespan of 8,000 hours is capable of being switched on and off at least 8,000 times.
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6. Can I replace all my incandescent bulbs with A-rated equivalents?
Yes, as a general rule you can source A-rated bulbs in the same shape as traditional bulbs and with the same fitting size. Because energy saving bulbs provide a slightly different light than that produced by conventional bulbs, there are some locations in which the Trust does not recommend switching to energy saving equivalents (e.g. over the bathroom mirror or in other places where it is important to have optimum colour rendering).

Start with the places where lights are on most often, and where the small differences in colour nuancing is not so important (e.g. in the entrance hall, bedrooms and children’s bedrooms).
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7. Where can I buy bulbs on the recommended list of A-rated bulbs?
In Denmark, energy saving bulbs are sold in many stores. Check the list of stockists and look for the Trust’s energy saving label in the individual stores.
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8. Is the light quality as good when fitting an A-rated bulb?
This depends on how and where you plan to use the light. Slightly poorer colour rendering has no practical significance in most case, unless you are putting on make-up in front of the bathroom mirror, or have a hobby such as sewing.

A bulb’s ability to reproduce colour is based on the CRI (colour rendering index) scale of 0-100, where the capacity of daylight to reproduce colour is rated at 100. An incandescent bulb’s colour rendering ability, which is 99, is very close to daylight. An ordinary A-rated bulb's CRI value is 80-85.

Choose a recommended A-rated bulb that gives a warm, not cold, light.

Read more about light and colour quality
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9. What is the technical difference between an A-rated bulb and an incandescent?
A traditional incandescent bulb produces light by heating up a metal filament inside the bulb so much that it glows.

An energy saving bulb works in the same way as a fluorescent lamp, where a coating on the inside of the bulb is stimulated by an electrical current which is, in turn, discharged by an electronic ballast mounted in the base of the bulb, in a two-part process that produces visible light.
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10. In terms of fire hazard, how safe are A-rated bulbs?
A-rated energy saving bulbs are not a fire hazard.
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11. What are C-rated and E-rated bulbs?
All light sources must conform to the EU Energy Labelling Directives on a scale of A–G, with A being the most energy efficient and G the least. Categories A and B denote energy saving bulbs, C and D use more energy, and categories E-G are tungsten filament bulbs and use by far the most energy.
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12. Why do A-rated bulbs not always fit my lamp sockets?
In 1970, Denmark agreed to implement a common standard which specified how the bulb holder should be made. So, there should be no difficulties with lights manufactured after 1970, but there can be problems with older lamps because the thread on the energy saving bulb may be too short. In this situation the only solution is to change the fitting.
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13. Does price have a bearing on whether an energy saving bulb can be categorised as being A-rated?
No. Energy labelling strictly relates only to a bulb’s power consumption and light output. Lifetime, light quality, colour temperature, price or other features are not important factors for determining whether a bulb is A-labelled.
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14. How can I be sure that the energy saving bulbs on the recommended list of A-rated bulbs will live up to the quality requirements that have been established?
We carry out random tests of bulbs featured on the list of recommended A-rated energy saving bulbs. A bulb is deleted from the list and the results are published if it fails to fulfil 1 or more of the requirements. As a consumer you will therefore always be assured of good quality if you use the A-rated list as a guide.
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15. Why does the Trust recommend that you replace 60 W incandescent bulbs with 15 W A-rated energy saving bulbs, when some producers state on their packaging that 60 W is equivalent to 11 W?
Bearing in mind that the amount of light emitted by an A-rated energy saving bulb and a conventional bulb is not exactly the same, you will need to choose an A-rated energy saving bulb that produces either slightly more or slightly less light.

The packaging often recommends that you replace a conventional bulb with an A-rated energy saving equivalent that produces slightly less light; for example, replacing a 60 W conventional bulb with an 11 W A-rated energy saving bulb.

Because the amount of light emitted by an A-rated bulb reduces slightly throughout its lifetime, the Trust recommends that you base your replacement on ‘1 number bigger’ (i.e. a 15 W A-rated bulb) to achieve an equivalent light over the bulb’s total life. And the saving in electricity is still considerable.
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16. Can A-rated energy saving bulbs cause stress, concentration difficulties and depression?
There are no unequivocal research results documenting that A-rated energy saving bulbs cause stress, concentration difficulties or other malaises. However, it is always important to ensure adequate, good quality lighting in all the places where people work. Avoid flickering and pulsating lights. You can do this by installing electronic high frequency (HF) ballasts, which are fitted to all energy saving bulbs produced today.
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17. Can I get A-rated energy saving bulbs which work in lamps with dimmers?
Yes. 2 different types of dimmable A-rated energy saving bulbs are available: One type can be dimmed using a standard light dimmer unit. Another type is dimmed by pressure combinations applied to the switch. You can see which pressure combinations you need to use on the packaging for the lamp or in the user manual.

The packaging will state whether an A-rated bulb can be dimmed or not.
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18. Can A-rated energy saving bulbs cause migraine and epilepsy
There is no research documenting that energy saving bulbs can trigger migraine or epilepsy.

Early examples of energy saving bulbs on the market pulsated 100 times per second, giving the impression that the light was flickering. This triggered attacks in some migraine and epilepsy sufferers. Today, all energy saving bulbs are fitted with high frequency electronic ballasts with around 60,000 oscillations per second. The combination of high frequency ballasts and the construction of energy saving bulbs means that in practice A-rated bulbs do not flicker at all.

However, some sufferers are claiming that new energy saving bulbs also trigger migraine and epilepsy attacks. But the connection has not been proved. Back to top

19. Is it true that it doesn't pay to switch off an A-rated bulb?
No, it's not true. As a general rule, you should always switch off lights when leaving a room.

There's a myth that it takes a lot of energy to switch on an A-rated bulb or a fluorescent tube. A-rated bulbs and fluorescent tubes require a relatively high starting current, but this has no impact on your electricity bill because the switch on process takes only a fraction of a second.
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