Do you know your CFL from your Halogen? Your Incandescent from your LED? Maybe now is time to find out about the new generation of energy saving light bulbs.  As lighting is responsible for about 18% of an ordinary household’s energy bill, reducing the cost of your lighting could result in some serious savings.

Check out our Energy Saving Calculator to find out just how much.

Types of Low-Energy Light Bulbs

Currently there are two sorts of low-energy light bulbs available in the UK , the CFL (Compact Fluorescent Lamp) and LED (Light Emitting Diode) and we have both available here.

The ‘old fashioned’ incandescent bulb has been phased out, although it is still available for industrial uses. You could be forgiven for getting confused with the ever increasing myriad of light bulb options that are now available under the ‘energy-saving’ banner. So here is our simple guide on all the different types available.

Comparison of Lighting Technologies

Traditional light bulbs

What we consider ‘traditional’ light bulbs, are more technically known as incandescent, tungsten filament, or GLS (General Lighting Service) bulbs. They were invented over 100 years ago with Edison’s original carbon filament being replaced with tungsten around 1906. They are extremely inefficient as they only convert about 5% of the electricity they use (and some say the average household bulb only converts around 2.2%) into visible light. How they work is that the filament is heated up until it glows and gives off that familiar yellowish light which is why they are called ‘incandescent’.  They don’t last very long as the filament gradually wears out through evaporation with an average life of between 750 and 1,000 hours.

Halogen light bulbs

These also use filaments but as they run at a higher temperature they are slightly more energy efficient than the traditional light bulbs and they last longer – between 2,250 and 3,500 hours. They often feature a parabolic aluminised reflector which gives them a very crisp bright white light. Because of this they are mainly used in downlight or spotlight fittings in kitchens and bathrooms, where the more intense light is useful.

They also waste energy by generating four times more heat than an average incandescent bulb, and the temperatures reached can be over 1,200 degrees. This can cause a serious fire hazard if they are fitted in unsuitable fixtures. The fire at Windsor Castle in 1992 the source of the  Queen’s  ‘Annus Horribilis’ was caused by a halogen lamp igniting cleaning fluid.

The downside of halogen spots is that you tend to use a lot of them (an average kitchen with downlighting will have at least 6) and the tendency is to use ones that are unnecessarily bright meaning more electricity is being used than really needed to light a room. So, if you don’t fancy moving to the lower energy bulbs available,  you can still save energy by simply downgrading the wattage of your halogen light bulbs.

In 2013 the EU Commission started phasing out D and E rated bulbs.

Compact fluorescents (CFLs)

Fluorescent lighting has come a long way since the old days of noisy buzzing strips that gave off a flickering sickly greenish light synonymous with institutions and factories. These days they are quiet and come in a range of colours which can mimic the traditional incandescent bulb.

CFL technology uses gas inside a glass tube which is charged with electricity until it glows and gives off light. The are ‘compact’ because the fluorescent tube has been wound around to only take up the same size space as a traditional bulb.

CFLs are phosphor-coated glass tubes containing inert gas and a small amount of mercury. The gas is charged with electricity until it gives off light. Different mixes of gas give different light colours which can match the warm glow of the traditional bulb.  The annoying flicker and buzz has been eliminated through the use new types of controlling ballast – the mechanism needed to alter the electric current flow and activate the gas.

To produce the same amount of light, they use only 25%-30% of the electricity compared to an ordinary bulb. That’s a saving of between 70-75%. They also last 10 to 15 times longer at around 10,000 hours or more.

The downside is that they can contain mercury which means they need to be recycled properly and they take time to heat up and produce light.

Strip lights or Linear Fluorescent Lamps (LFLs)

These are the more traditionally shaped fluorescent lighting strips, but they use the same technology as CFLs. They are much improved over the old strips in that they are more energy efficient, don’t buzz and flicker and light up more quickly. With a better quality of light and a range of colours, they can be used in kitchens e.g. under cupboards to illuminate work surfaces and above bathroom mirrors.


LEDs are simple semiconductor devices that produce light when electricity flows through them. The technology is improving almost daily and the limitations of the early versions – such as harsh bright and very directional light – are dropping away.

LED like-for-like replacements are now available for almost all the types of bulbs you are likely to want to use in the home. A typical 35W halogen replacement LED will use as little at 4W to produce the same amount of light. They are also go on instantly which is better than the CLF equivalent. They are also available in strips which are incredibly durable, which means new lighting effects such as ‘toekicks’ can be created.

Whilst they are still more expensive than the other types of bulbs, they last much longer with 20,000 to 40,000 hours being quoted by manufacturers. One journalist in The Guardian (Adam Vaughan, 8th June 2012), calculated that using 40 LED bulbs in his new-build home for an average of 2.7 hours a day (the Energy Trust’s typical use figure) running costs would be £23 annually compared to £287 for staying with halogens.