You’re probably expecting the usual fluffy “how to” article – the sort that opens with a few insipid generalisations before meandering into a less than thunderously convincing argument vaguely related to the title. If so, prepare to be disappointed/pleasantly surprised (delete as appropriate); I have neither the time nor inclination and frankly the data speaks for itself. So let’s pitch in and start doing some math.
A typical mains powered halogen lamp (as commonly found recessed into ceilings) consumes 50 watts, can be purchased for about 2, lasts up to 2,000 hours, and will cost 12 to run for those 2,000 hours. The running cost is worked out using the standard rate of 0.12 per kWh and assumes modest average use of 3 hours per day which equates to roughly 1,000 hours per year.
A GU10 LED replacement (i.e. an LED with near identical performance characteristics, such as the Sharp Zenigata) consumes 4 watts, costs at present 24 to buy, has an effective lifespan of over 40,000 hours and will cost 0.96 to run over the same time period.
At first sight it would appear that the LED costs way more simply because it costs so much to buy in the first place. But let’s look more closely at this picture to uncover the “real world” perspective.
To begin with, to compete against the lifespan of a single LED requires replacing the halogen 20 times, which brings the true purchase price up to 40 (20 x 2) which is nearly double the LED’s 24 price tag.
Second, if we view things over the lifespan of the LED rather than the feeble lifetime of the halogen then we incur running costs of 240 for the halogen compared to 19.20 for the LED.
Lastly, let’s also account for that “real” difference in purchase price; so over 40,000 hours a single halogen (plus its 19 replacements) will run up a bill of 280 but swapping it for an LED will instead incur a total of 43.20. Forget looking for 10% savings here or 25% there, we’re staring at the reality that halogen lamps are over 1000% (yes, one thousand percent) more expensive to own and run than equivalent LEDs.
Even when the purchases prices are accounted for, halogen lighting is still over 700% more costly. Halogen lamps appear cheap because each costs relatively little to buy, but the truth is they actually end up costing twice as much as an LED because of the frequent replacements, and they are massively more costly to run. LED’s are a completely different ball game and interestingly sometimes cost more to buy than to operate (as this example illustrates).
Needless to say, this illustration is somewhat low-scale and examines just one very lightly used light bulb. However, I noticed en-route from my North facing (hence gloomy) kitchen that 10 down lights stay on in there from early till late, then passing through the hall I spotted 4 more and here in my office 6 more are switched on for a good 6 hours daily.
Just this little lot therefore clock up between them slightly over 100,000 hours annually ((6 * 6 * 365) + (10 * 17 * 365) + ((4 * 17 * 365)) which would present a bill of 600 (50w * 100000 hours * (0.12/1000)) using halogen lamps, but instead comes in at a much more agreeable 48 with LED lights. And that’s just for these 3 rooms.
Take a few more practical examples – offices, shops, hotels, hospitals, airports, the list goes on – where artificial lighting is on almost constantly; throw in some currency symbols and suddenly mathematics mutates into economics and we’re looking at eye-watering sums of money.
We have demonstrated that, despite initial appearances, the purchase price of an LED is about half that of an equivalent halogen lamp when you account for the repeat-purchases as it wears out. We have also calculated that overall electric lighting using halogen lamps is 12 times more costly than replacing them with LEDs. So the one question remaining then is this: why would anyone stick with halogen lamps?
