Energy
How many politicians does it take to change a lightbulb? PDF Print E-mail
Written by Richard Forster, Lighting Engineer, BSRIA, 2008   

Governments intent on reducing carbon dioxide emissions from buildings are thinking of banning the old-fashioned, energy-hungry lightbulb. But are compact fluorescent lamps (CFLs) any less damaging to the environment? Richard Forster goes behind the hype to find out.

  • Can tangible savings be achieved by switching from lightbulbs to CFLs?
  • Is there a difference in the light quality provided by CFLs and lightbulbs?

Having entered into international agreements to tackle environmental pollution, how are such targets to be reached?

Governments around the world are considering whether to enforce the total replacement of the humble lightbulb (GLS) with low-energy compact fluorescent lamps (CFLs).

One way to reduce carbon dioxide emissions is to cut back on the consumption of electricity.

Most of the UK's electricity is generated by burning hydrocarbons. The domestic consumption of electricity is about 33 per cent of total national use - and this is growing steadily per household, while the stock of housing is also increasing.

To assist policy making, the Department for Food and Rural Affairs (DEFRA) produced evidence in its 2006 Market Transformation Programme that quoted the following figures:

  • Domestic lighting is mainly by GLS lamps.
  • Eighty-nine per cent of the total number of lamps covers the wattages 40W, 60W and 100W.
  • The average household had 21.6 lamps in 1996. The Market Transformation Programme assumes this will rise to 25.9 lamps by 2020. These figures were originally prepared by the Electricity Association in 1996 (Figure 1).

The major cost associated with lighting is the electricity it consumes. Therefore changing to CFLs can reduce consumption by 75-80 per cent.

However, the initial cost of the lamp is 10-20 times higher. Accountants say they can demonstrate break-even costs within about a year of use. Unfortunately, the savings are rarely apparent.
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Figure 1. Domestic lamp market share 1996.

Savings with smoke and mirrors


As seen in Figure 1, in 1996 (the most recent reliable data), compact fluorescent lamps only accounted for 3 per cent of the total installed lighting.

It is reasonable to assume this has since doubled, but no new research has been carried out for over 10 years.

The initial investment of purchasing a CFL is obvious, particularly compared with the markedly cheaper GLS immediately next to it on the shelf.

By contrast, the savings in electricity bills are divided into quarterly segments and aggregated with other appliances and uses, such as cooking, cleaning and entertainment equipment.

As a consequence, savings are not visible to the consumer. They are also masked by larger electrical loads.

Finally, lamps are only purchased when needed. The longer life of CFLs will tend to pass unnoticed.

The economic arguments have strengthened in recent years as domestic electricity tariffs have recently undergone dramatic rises. Figure 2 is based upon the unit price to the author from Southern Electric.

Whatever energy policy is adopted by the government, it will entail major capital investment, importing electricity from abroad and probably the imposition of green taxes. It is unlikely that electricity prices will fall in the short- and medium-term.
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Figure 2. The dramatic rise in domestic electricity tariffs (based on figures supplied to the author by Southern Electric).

Technical arguments


This not only a domestic issue. There are numerous major industrial and commercial organisations who fail to use efficient lighting simply because of financial inflexibility.

This inflexibility is caused by the inability to transfer funds from operating and maintenance budgets into capital investment. This compromises attempts to achieve savings.

The comparative technical performance of GLS bulbs and CFLs increases the confusion. The marketing of CFLs suggests that there is no significant difference in the quality of light they provide compared with GLS lamps.

It is certainly true that the light from CFLs is the same as that from fluorescent lights that people experience during their work and leisure time in offices, shops, factories, schools and sports halls.

But if this lighting is adequate for daytime activities, why is it not suitable for the home?

The answer is that the domestic environment is different and can involve more critical tasks than at the workplace, such as food preparation and colour discrimination of fabrics for clothing and décor.

At the other end of the scale there are nearly 4,000 accidental deaths in the home - considerably more than die on UK roads - every year.

Although accurate statistics are not readily available, poor lighting could be a contributing factor.

GLS lamps have been subject to strict British Standards since 1921. The consumer has confidence in the performance of the lamps.

There is no equivalent standard for CFLs, and the performance varies between manufacturers.

Replacing GLS lamps with CFLs is clearly advantageous, economically and environmentally, but their effects on lifestyle have not been seriously considered. The lighting will be different in appearance, application and use.

In new dwellings domestic lighting suffers from inadequate installation. The formula is based upon the minimum number of lighting points arranged with the shortest cable runs. Consequently, lighting is often wrongly positioned and poorly controlled.

For some rooms, where there are fixed working positions such as in kitchen and bathrooms, permanent lighting can be installed.

For other rooms, the lighting needs are determined by the layout of furnishings particular to a set of occupants. A more flexible arrangement is needed if the lighting is to be both effective and efficient.

While the aim is for CFLs to be very similar to GLS lamps, they are clearly not an exact replacement. There are advantages and disadvantages that need to be clearly stated if CFLs are to be widely accepted.

The limited market penetration suggests that ignoring the differences and claiming universal compatibility will lead to consumer rejection. Politicians should develop the power of persuasion rather than the imposition of regulation.

Finally, removing the GLS cash-cow from tungsten filament manufacturing may cause other lamps to cease production, as it would no longer be viable to manufacture materials such as glass bulbs, drawn tungsten wire and even bayonet lamp-caps.

Richard Forster is a Lighting Engineer at BSRIA. Please visit www.bsria.co.uk
 
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