Greening your home – Energy efficient lighting

light bulbs

Like bicycles, filament bulbs are a design that has hardly changed over the last century. However, unlike a bicycle, which allows a person to travel at 10–15 mph, using no more power than they would require to walk, filament bulbs waste 95% of the electricity they use as heat. Indeed, in many homes the use of tungsten filament bulbs can account for half the annual household electricity bill. Or at least it used to before the sale of incandescent bulbs was banned following an EU directive.

As well as the massive environmental benefit of reduced energy consumption, the change away from the use of incandescent bulbs has saved us money. For although a new generation of compact fluorescent, halogen and LED bulbs might cost more to buy, they last far longer and cost far less to use.

The demise of the incandescent bulb does not mark the end of the story as lighting technology marches forward. The light-emitting diode (LED) technology that has transformed bicycle lights by providing cheap, bright and robust illumination is slowly but surely making its way into our homes.

An LED filament bulb that draws only 2 watts of power, but emits the same light output as a 25-watt halogen incandescent bulb costs less than £3. On top of the energy saving, the bulb is capable of 150,000 hours of operation and/or 15,000 cycles. In other words, it outperforms a tungsten filament bulb in every respect.


home insurance

Energy efficient lighting is one of the small steps that we can take to reduce our carbon footprint. Join us over the following weeks and months as we explore other ways of greening our homes. Sign up to our weekly newsletter to get energy saving advice delivered straight to your inbox.

Greening your home – A quick guide to light bulbs

a guide to light bulbs

Incandescent bulbs
Least energy-efficient option and the shortest lifespan, which can be as little as 750 hours.

Fluorescent lighting
Extremely long lasting with a potential life of over 30,000 hours. However, this lifespan is only possible in applications where they are left on for long periods of time. Quality of light can be harsh on the eye if not obscured.

Compact fluorescent lights (CFLs)
CFLs might not last as long as traditional fluorescent bulbs, but they offer a variety of colours and shapes.

Halogen bulbs
More efficient and longer lasting than incandescent bulbs, with a crisp light.

LED lighting
Not the cheapest, but by far the longest-lasting and efficient option.

Mercury Vapour bulbs
Mercury vapour lamps are more energy efficient than incandescent and most fluorescent lights and boast a bulb lifetime of over 20,000 hours and a clear white light output. However, their warm up time of 4-7 minutes makes them unsuitable for domestic applications.

Induction bulbs
The induction bulb is a gas discharge system in which the power to generate light is transferred to the gas within the bulb via an electric or magnetic field, thus doing away with the need for internal electrodes – an arrangement that extends the life of the lamp.

Sodium bulbs
A low pressure sodium-vapour lamp is a highly efficient light source, but its yellow light generally restricts its application to street lamps and the like.

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  1. Susan Johnson


    Please advise whether it is worth swapping from energy efficient bulbs (CFLs) to LED for ‘normal’ light bulbs – my understanding is that the savings is around 20-30%. What can one do with CFLs that are still usable – it seems like a waste of embedded energy to send them to landfill. I find the 95% saving figure problematic because I doubt many people have any of the incandescent ones left.

  2. Robert


    Paragraph 4 starts…”An LED filament bulb that draws….”

    Is this a typo? If not, what is an LED filament bulb?

    • The ETA


      Robert, an LED filament light bulb is an LED lamp which is designed to resemble a traditional incandescent light bulb with visible filaments for aesthetic reasons.

  3. Tony Williams


    Susan Johnson is right – few people will still use ordinary incandescent lamps, and are likely to be switching to LEDs from CFLs. I doubt that the saving is worth it while the CFL still works. What will be worth doing is to switch to a LED when the CFL packs up. CFLs last much longer than incandescent lamps but not as long as LEDs are supposed to.

    There are two problems with LEDs. Most of them are larger than incandescent lamps for a given light output, so they may not readily fit inside an existing light fitting. Some sellers provide detailed information about the LEDs they sell including dimensions, but not all do so. The second problem is how you measure the light output. We knew where we were with 25 watt lamps, 60 watts, 100 watts. LED outputs are presented in lumens. But you find one lamp claiming to be “75 watt equivalent” with an output in lumens hardly larger than another that says it’s “40 watt equivalent”. And comparing 840 lumens with 1130 is much less straightforward than comparing 40 watts with 60. So buying LEDs requires a bit of thought.

    There are so-called LED filament lamps – they look as if they’ve got filaments but they are economical LEDs.

  4. Martin Bishop


    We use most lighting in our homes during long cold winter evenings when the central heating is on, so the heat dissipated by filament bulbs isn’t wasted, it reduces heating costs.
    Obviously, there are issues of overall efficiencies but one tends to offset the other. Don’t look at lighting energy costs in isolation from other energy use.
    If you just want lighting, by all means use high efficiency LED bulbs, but the overall savings are nothing like as high as the marketing people would have you believe because they are selective in their use of data, and don’t look ate the whole picture of domestic and commercial energy usage.

  5. Michael Davis


    Incandescent bulbs may have been “banned”, but due to a loophole in the regulations, they are still widely available. The regulation did not ban so-called “Heavy Duty” bulbs, intended for “Rough Service”. These have a filament with extra support compared with normal filament bulbs & are available in many retail outlets, evidently being sold as replacements for the old regular filament bulbs. Shame really as they are very inefficient compared with LED replacements & will cost the users dearly over the bulb’s lifetime.
    The point above about the wasted electricity being consumed by filament bulbs is valid in that they do heat up the surrounding environment, but of course this is heat that may not be required. Also, thinking about bulbs used for interior lighting, these are normally positioned near the ceiling whereas heating is required & usually provided at or close to ground level.

  6. John Williams


    I really dislike CFL bulbs – particularly the way they get brighter as they warm up – and was so happy that LED bulbs came along to save me. Almost every light in our house is LED – I think we have two CFLs and two halogens that came in the cooker hood – they’ll be replaced with LEDs when they eventually die.

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