Save Serious Money With Modern LED Lighting
Posted by Louisa Kennicot on July 4th, 2009
If you were anticipating a typical “how to” piece, you know the type, long on bland verbiage and short on factual information that scarcely manages to argue the case suggested by the title, then you’re in for a let down (or an unexpected surprise, depending on your viewpoint). I really can’t be bothered and quite honestly I hardly need to write anything at all – the numbers say it all, so let’s get stuck in.
A regular mains voltage halogen light of the type ubiquitously installed in ceilings requires 50W input power, costs about 2 to buy, will last maybe 2,000 hours and over that same period will use 12 worth of electricity; this is calculated by assuming very modest annual usage of 1,000 hours (about 3 hours each day) and the currently accepted average electricity price of 0.12 per kWh.
An LED replacement for the halogen lamp (a high quality, near identical performance product similar to the Sharp Zenigata for example) will today cost 24 but uses only 4W and lasts for over 40,000 hours, and over the same 2,000 hours runs up an electricity bill of 0.96.
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.
Secondly, if we run our comparison using the life span of the LED instead of the woefully short-lived halogen we see that where the LED uses just 19.20 worth of electricity, the halogen burns its way through 240.
As a final step, let’s now add together the running costs over 40,000 hours with the “real” purchase prices, and immediately it’s clear that the total bill for the LED will be 43.20 as compared to 280 for the halogen lamp (and its many replacements). If you thought this would be an exercise in scraping out 10% or even 50% savings, think again – the numbers do not deceive, halogen lamps cost 1000% more than LED equivalents.
Even with the initial investment figures added back in, halogen lighting is easily 700% more expensive. Interestingly also, in this example the LED actually costs less to run than to buy. The halogen lamp is superficially cheap to buy (but as we saw ends up costing nearly twice as much as the LED due to constant replacement costs) yet hugely expensive to run. It’s a totally different ball game.
Of course, this is a very scaled down example applied to one little-used light bulb. I have just walked from my North facing kitchen where 10 down lights are almost permanently on from 7:00 A.M. to midnight, thru a hall with little natural light and 4 more halogen lamps, into my office where a further 6 glow maybe 6 hours a day.
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.
If we look at real life examples such as shops, offices, hospitals, hotels, airports and so on, where it is commonplace to use artificial light almost all the time then things get really interesting. Economics is little more than mathematics with currency symbols, and if we extrapolate our simple calculations above the numbers start to resemble seriously big bucks.
We have already established that the purchase cost difference between the two gets cancelled out about halfway through the lifespan of the LEDs and that over time it’s actually much cheaper to buy 1 LED rather than replace a halogen lamp 20 times. We also now know that halogen lamps cost 12 times as much to run as equivalent LEDs. So why then would anyone choose NOT to switch to LED?