Halogen vs LED GU10s

How does an expensive LED “spotlight” compare to a cheaper halogen one when their running costs are taken into account?

Just about everywhere you look these days, your eyes get seared by cheap-and-cheerful halogen spotlights – shops, restaurants, pubs, hotels – perhaps even in your own home. But how many of us realize just what carbon-greedy wallet-draining little critters they are?

This is the typical halogen spotlight – a GU10 base with a 50 Watt rating giving off about 250 lumens of light for about 1500 hours before it fails. But as it’s cheap, (and 1500 hours is a whole year at around 4 hours a day) it doesn’t really matter does it? Well, let’s start to crunch numbers. 50 Watts over 1500 hours is 75kWh of electricity, which if you pay the same sort of price as me (about 14p / kWh) is £10.50. So, over the 1500 hr life of the spotlight, it’s going to cost you about £11.85 all up, including initial purchase. And now you need to buy another, and start all over again.

Here’s the modern dimmable LED alternative – 10x the cost on the face of it, but notice the power rating – 3W rather than 50W. OK, it’s a slightly lower light output – 170 lumens (for 50,000 hours!), but I have used a “dimmable” comparison as this gives the LED version the highest initial cost to illustrate the point. So over the same 1500 hours to the halogen spot failing, it will use 4.5 kWh of electricity, which costs about £0.63, so the total for the first 1500 hours is £13.13.

But the LED bulb is still good for another 48,500 hours (roughly!), and while the next 1500 hours with your replacement halogen bulb will cost you another £11.85, the LED will continue doing its job for further 1500 hours using all of 63p in electricity. And the same will happen for the next 1500 hours after that, and the one after that. So, unless you’re planning to use the bulb for less than 1500 hours, the LED version is quickly cheaper overall even though it costs 10x as much as the halogen bulb to buy.

(And I’ve not factored in the hassle or cost of getting to the fittings to change the bulbs when they fail, or ordering / maintaining replacement stock, etc – someone has to do it, and it all has a cost. Or running an air-conditioning system to keep the places where you use halogen bulbs cool as they convert a lot of that 50W into heat …)

That’s my “wallet-draining” comment sorted, so what about the “carbon-greedy” bit? UK grid electricity gives off about 500g of CO2e for every kWh of electricity in the grid, so over its lifetime, a single halogen bulb is responsible for about 37.5 kg of CO2e emissions from its power use alone (equivalent to driving about 170 miles in an average car), while the LED alternative is responsible for a mere 2.25kg (10 miles) – a 94% reduction.

It’s a bit of a no-brainer really, isn’t it? So bite the bullet – next time you need to replace a halogen spot, pop in an LED one instead and not only save yourself money (and buffer yourself against future electricity price hikes …), but reduce your carbon emissions too.

I often provide cost/carbon comparisons like this on selected existing fittings and my alternatives as part of my services when reviewing the energy consumption of premises.

(Prices quoted & lamp images are taken from http://tinyurl.com/3vv63pa on date of posting and include VAT but exclude delivery)

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5 Responses to Halogen vs LED GU10s

  1. John Merison says:

    I agree with your comments Barry having supplied and fitted the Led lighting in all sorts of area’s both private and public sectors all over the midlands and beyond we have software the gives the payback and costs and can now provide an energy saving loan from siemans and the carbon trust.

  2. Stephen says:

    I’m interested in your comment that a halogen gives off 250lumen of light. A new MR16 can produce up to 900lumen and a GU10 600-700lumen. I do not believe that anything less than a 500lumen LED truly gives a comparable light output to halogen downlighters.
    Having said that, in my kitchen my 280lumen LED downlights give plenty of light for my domestic requirements as the lamps have a narrow beam angle and are directed to where the light is needed.

  3. Barry Smith says:

    Stephen – If you have costs, power use and life for a 500 lumen dimmable GU10 LED, I will quite happily add an addendum to the article.

    John – That’s a very good piece of info to know! Thank you.

    • Alan Farmer says:

      Hi Barry,

      by the end of the week our LED Lighting catalogue will be online where you will be able to see the specs for GU10’s MR16’s and a host of others. A 6watt LED GU10 will give you between 360 and 440 lm and a 9 watt between 580 and 620 lm

  4. Colin Tattersall says:

    I suspect you’ve probably read it, but I think you would enjoy reading the book “How bad are bananas” by Mike Berners-Lee. All about carbon consumption and easy to read / relevant to every day living.
    Also, there’s link in a Verulam comment in The Structural Engineer 7 June 2011 to a very interesting discussion of the environmental / climate issues we’re all currently facing. For a science article it pretty easy reading. Not sure if I’ve got the quote exactly correct but…
    “If everybody does a little bit, well all we’ll achieve is very little”

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