Light bulbs and energy saving – The facts
Energy saving can best be described as the most energy efficient option for the application and under the circumstances. It would be unreasonable to fit large CFL lamps to a glorious crystal chandelier where the lamps are in view. Similarly it would be sheer folly to try and light a football stadium using CFL lamps for their next evening fixture.
There is a great deal of misinformation and confusion about the energy saving characteristics and benefits of different types of replacement lamps. There has been poor reporting on the phasing out of the 100w, 75w, 60w and 40w traditional household light bulb (incandescent lamps). Incandescent lamps are not being phased out completely but inefficient lamps that do not meet an energy rating of at least ‘C’ are being phased out. It is still possible for you to select the correct lamp, of the right brightness and colour for almost any application. The alternatives available are as good as or better than the old fashioned household light bulb. Some cost a little more but consume far less energy, last far longer and save money during their lifetime.
Incandescent and CFL (Compact Fluorescent Lamp)
I hear people say that a 60w incandescent lamp is cheaper than a CFL. Well, this is only true if you use them as door stops. As soon as you use them, it becomes far more expensive for you and everyone else to use the incandescent lamp. CFL makers claim an 80% energy saving over an incandescent light bulb. In reality, this can vary between 60% and 80% depending on manufacturer. They also claim a 10-year lifespan. It is important to know that the ten-year lifespan is calculated at 3-hours average use per day. It therefore follows that if the lamp is used for more than 3-hours per day, it will not last ten years.
The current generation of CFL lamps achieve 80% brightness within three seconds and full brightness within ten. The days of doom and gloom for up-to three minutes once the lamp is switched on are long gone. They are also available in different colour temperatures from a warm white to a cool white. The warm white gives the same sort of lighting effect as an incandescent light bulb. The only disadvantage of CFL lamps is that they are ugly and not well suited to being viewed. They are best hidden by a shade.
It has been estimated that if people in the UK switched to using energy saving lamps it could reduce the amount of carbon dioxide released into the atmosphere by 2.3 million tonnes a year.
LED light bulbs are made from either clusters of light emitting diodes in light bulbs or three to seven high powered light emitting diodes in spot lamps. There is no doubt that LED lamps are the future of home and commercial lighting. They are already everywhere but you probably don’t notice them unless you look closely.
Good quality LED spot lamps have been available for a number of years now but it has been problematic for the manufacturers to construct a light bulb of sufficient quality. The main reason is that LED’s give directional light, which means that they are excellent for something like a torch, car headlight or spot light but poor for general all-round room lighting.
Manufacturers have now produced domestic light bulbs that are bright enough, with good colour rendition and a lifetime of around 30,000 hours. We are now at the stage where a 7.5w LED light bulb can replace a 60w incandescent lap with no loss of illumination or light quality.
Replacing a 50w spot lamp with a good quality non-dimmable LED equivalent will cost between £12.00 and £18.00 depending on manufacturer, whilst replacing a 60w light bulb with a 7.5w equivalent can cost a whopping £40.00 – £60.00. Replacing a 25w candle lamp with a 4w LED will cost between £15.00 and £20.00.
The table below shows the costs of using different types of lamps, assuming 3hrs use per day. The total cost includes the cost of lamps and the electricity used. Electrical costs assume a rate of 11p per Kw and do not take into account any future energy cost rises.
|Lamp Type||Lifetime||Cost per lamp||Electricity Used||Cost – 30,000hrs|
|60w Light Bulb||1,000 hrs.||£1.95||1800Kw/h||£256.50|
|13w CFL||10,000 hrs.||£4.95||390Kw/h||£52.80|
|7.5w LED||30,000 hrs.||£40 – £60||245Kw/h||£66.95 – £86-95|
The table shows the total cost for each type of 60w or equivalent lamp over a 30,000 hour period and assumes thirty replacement lamps for the incandescent bulb and three for the CFL.
It can be seen from the table that the best deal at the moment is the CFL light bulb, but don’t discount the LED lamp just yet. It is very likely that the cost of LED lamps will decrease considerably over the next couple of years, so keep looking from time to time until they are a real viable alternative light source.
About the author
Sye Yehya is the managing director of Universal Lighting Services Ltd who has a wealth of specialist experience in the lighting field. The business specialises in all aspects of home lighting, together with their associated products. They are up to date with all aspects of lighting and in particular the energy saving and low energy options available to you today and those that will become available in the near future.