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I have just swapped over my old, energy hungry, 60w GLS light bulbs at home and replaced them with some top of the range, fresh to the market, professional, proper expensive LED ones. The LED lamps in this example can be seen on the Fastlec website here I wanted to look at an extreme case, to see if the figures still work and to ensure that we were achieving at least an equivalent level and quality of light output in a domestic situation. These particular lamps currently retail at £29.99, so they really are at the top end of the market. That being said they are incredibly bright (brighter than the 60w ones they replace), start instantly and the colour is perfect. Average usage of a domestic light bulb is up for argument, but its generally taken at 4 hours per day. 4 hours x 365 days gives us 1460 hours per year Old 60W GLS Light Bulbs:
The old 60w GLS bulbs work out at 0.06KW (60 / 1000)
0.06KW x 1460 hours = 87.6 kilo watt hours (these are the units we are all billed for on our electricity invoice)
Taking electricity costs at 15p per KWh, that's 87.6 x .15 = £13.14 per light bulb per year.
I changed 11 light bulbs in the house x £13.14 = £144.54 cost of the electricity for all 11 bulbs for one year.
New 11W Performance LED Light Bulbs:
The new 11w LED bulbs work out at 0.011KW (11 / 1000)
0.011KW x 1460 hours = 16.06 kilo watt hours (these are the units we are all billed for on our electricity invoice)
Taking electricity costs at 15p per KWh, that's 16.06 x .15 = £2.41 per light bulb per year.
I changed 11 light bulbs in the house x £2.41 = £26.51 cost of the electricity for all 11 bulbs for one year.
So thats £144.54 - £26.51 = £118.03 electricity cost saving each year (1460 hours). The life of the LED performance lamp is 30,000 hours. 30,000/1460 = 20.55 Years So the total electricity saving for whole life of the 30,000 hour LED bulbs is actually £2425.51 IF ENERGY COSTS STAYED THE SAME FOR 20 YEARS! In reality, with gradual increases in energy costs over that period, the saving is likely to be double to triple that.
The 11 LED Lamps cost £29.99 each inc VAT which gives us a total cost of £329.89.
11 x 60W GLS standard domestic light bulbs costing 30p each gives us £3.30 but they only last an average of 1000 hours so you will need to re-buy them 30 times to cover the 30,000 hours life of their LED equivalent.
30 x £3.30 = £99
So the investment difference is £329.89 - £99 = £230.89
So the payback period (assuming you've fixed your energy rates for the duration) is £230.89 (investment) / £118.03 (Electricity cost saving per year) = 1.96 years At this point you should still have in the region of 18.59 years lamp life left in the performance LED lamps. Conclusion: Bearing in mind that you may be able to find a lesser performance LED lamp (not everyone is as fussy as I am at home about light output and colour) for less and the fact that you can feel warm and fuzzy about helping to save the planet at the same time, it would appear that changing old energy hungry light bulbs for the new generation, high output, low wattage, quick start LED equivalent is a no-brainer.