LED (light emitting diode) lighting uses less power than other types of household bulbs. Typically a standard 60W light bulb can be replaced by a 6W LED. Even ‘energy saving‘ CFLs (compact fluorescent light), at around 18W, use more power than a like-for-like LED. So the obvious benefit is they will use less electricity ultimately lowering your bill and reducing greenhouse gas emissions. In the UK 18% of a typical household’s electricity bill is from lighting
As the cost of LED lighting has come down to a more affordable level more and more people are considering LED lights for their homes and places of work; however, replacing all the light bulbs in the house or work place is often not financially viable. Below I have demonstrated a number of situations where changing to LEDs make a lot of sense.
When is it good to replace conventional light bulbs with LEDs?
In a situation where lighting is used for several hours per day and/or there are multiple bulbs in use; for example, halogen downlights or strip light in a kitchen or bathroom, fluorescent tube lighting in a workshop or garage, flat panel lights in shops or offices.
9 halogen downlight bulbs in a kitchen or bathroom:
9 x 42W halogen downlights that are used 3 hours a day for 320 days of the year (excluding holidays and trips away from home) will consume 362kWh per year and at 0.13p per kWh will cost £47.17 a year to run. In comparison 9 x 5W LEDs will consume 43kWh and cost £5.62 per year. If the material cost of an LED bulb is £3 then the break even point comes in the first year. In the domestic setting this, and situations where multiples spot lights provide the lighting, are probably the most obvious ones to upgrade.
LED spot light are designed to directly replace halogen bulbs and you can typically buy them with a 5 year guarantee. They are rated to last 30,000 hours – that’s 45.5 years at three hours use per day (excluding holidays). LED spot light run cooler than halogen bulbs which can reach temperatures that scorch their surroundings especially in and insulated ceiling. I once found a dead mouse laying across the top of a halogen spot light dessicated and singed!
6 (5ft twin) fluorescent lights in a mechanics workshop:
12 x 58W Fluorescent bulbs (T8 tubes) used 9 hours a day for 257 days of the year (excluding holidays, Sundays, half day Saturdays) will consume 1609kWh per year at an annual cost of £209.28. Replacement with Equivalent LED tubes consumes 610kWh per year and will costs an annual £79.38. At a material cost of £136 the break even point come early in the second year. Here though a half days labour may be required to bypass the electronic ballast (depending on the setting).
Again expect a 5 year guarantee and in this setting 30,000 hours is 13 years. A big advantage in a garage workshop is LEDs will come on instantly without a warm up period.
8 Flat panel lights in a shop:
Let say the existing lighting in this situation is recessed ceiling panels each comprising four 18W fluorescent tubes. In this situation 8 panels will use 576W and during a typical year (6 days a week minus Bank Holidays) used for 10 hours a day will consume 1756kWh and cost £228.38 to run. Replacing these with 45W LED panels would over the year use 1098kWh and cost £142.74. At a material cost of around £300 (assuming there are no labour costs) then a break even is reached in the beginning of the third year.
Some flat panel lights are rated to 35,000 hours and in the setting above will last 11.5 years. Whilst the savings are not as quick to come with LED flat panels, even with a days labour installing them a break even point is reached in the 6th year. What you also get with LED panels is an even light that come on instantly without flickering or a warm up period and you don’t have the annoyance of replacing that single flickering tube that’s reached the end of it’s life.
Some more information about LED
People may switch to LED for any number of the reasons already covered above but if your motive is environmental then switching your lighting to LED is probably the single most important change you can make after insulating you loft and draft proofing your home – see this article that compares the environmental impact of different light bulbs, and this one.
Of course, as with any electronic device, their components and circuit boards do contain trace elements such as arsenic and lead, however, unlike CFLs bulbs LEDs do not contain a vapour doped with Mercury that escapes into the environment every time one is broken. If when LED bulbs reach the end of there life they are disposed of correctly and their circuits boards recycled then they are no more harmful to the environment than any other electronic component.