60W lightbulb alternatives

The promise of a new LED equivalent to the now-phased-out 60W tungsten filament bulb prompted me to do a quick energy & cost comparison of the original tungsten lamps and the available alternatives. Here’s what I found.

60W tungsten filament lamps lasted approximately 1000 hours, over which time they used 60 kWh of electricity, for which I pay roughly 14p/kWh, or £8.40 over the life of the bulb.

The current alternative, a 13W CFL bulb, varies hugely in cost depending upon where you buy it, but you should be able to get a decent quality one for around £5.00. Over the same 1000 hours as a tungsten lamp, it will use 13 kWh of electricity at a cost of £1.82 – a total cost of £6.82 for the first 1000 hours.

CONCLUSION 1 – Even if you have a stock of unused tungsten filaments bulbs, don’t bother “using them up” – throw them away now and replace them with 13W CFL bulbs – you will save money very quickly.

As a decent CFL can be expected to last around 10 000 hours, the savings get even better, and over its life the total cost of a CFL would be around £23.20, This is equivalent to ten 60W filament bulbs used one after the other (if you had them) which would cost you £84.00 in electricity alone.

Not everyone likes CFLs though, so it’s good to see that the UK Technology Strategy Board held a competition for proposals to develop a low energy equivalent to the “standard” 60W bulb that would fit into the same “envelope”. The contract was won by Zeta LED Technology, and they have recently announced that the lamp should be available in 2012. As might be expected, the lamp is LED-based, has an 8W energy use, gives off 650 lumens at a “warm white” colour temperature of 2800 – almost identical to tungsten lamps – and has a life expectancy of 36 500 hours. The manufacturers anticipate an initial cost of £20/unit, dropping to £10/unit once into volume production.

So, over the 10 000 hour life of the CFL lamp, the new LED lamp will use 80 kWh of electricity at a cost of £11.20 – £31.20 in total at £20 / unit – but only £21.20 in total once the new lamp is in volume production, less than the lifetime cost of the equivalent CFL (£23.20).

CONCLUSION 2 – Unless you feel very strongly against CFL’s, on the basis of cost alone you should stick with them for a few years until volume production brings down the price of LED lamps. 

In the same way as CFLs last far longer than filament lamps, LEDs are expected to last far longer than CFLs. Over its 36 500 hours life, the LED lamp will use £40.88 in electricity, whereas 3.65 CFLs will have used £66.43 in electricity. You will also have had to buy four CFL lamps rather than just one LED lamp, so there are long term economies there too. (Note that 36 500 hours is 25 years at 4 hours per day!)

CONCLUSION 3 – In the long run, LED lamps offer the best value, especially once the unit price has dropped, or even straight away if you run them a long time every day.

(CONCLUSION 4 – If you buy the new LED lamps for your own home, take them with you when you move!)

More information on the new LED lamps can be found here:

(Note that the cost comparison ignores any increase in the cost of electricity over the period being considered. Increases in energy cost will always favour lower energy alternatives.)

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2 Responses to 60W lightbulb alternatives

  1. Andrew Kinsey says:

    Barry, at a certain large scale resi project in the east end of london which is being delivered for a large sports project next year that I worked on, they have installed 1000s of 7w Philips LEDs similar to those you describe above. Net result will save over 5,000t CO2 every year. Costs are dropping rapidly and technology is improving rapidly.

    Along similar lines you can also now get an LED tube to replace fluorescent tubes for temporary site lighting. Last year – cost £180 (vs about £45 for fluro tube). This year it is down to £60! Payback less than 1 year.

    You have to watch out – some of the cheaper ones have variable light output due to the uneven phosphor coating needed to turn blue LED light white.

    Regards

    Andrew

    • Barry Smith says:

      Hi Andrew,

      Thanks for your comments – its good to see LEDs getting greater acceptance. I’ve previously written about a GU10 LED / Tungsten comparison as well that showed clear savings, but as you say, quality can be a big issue. I’ve written this one because the LED equivalent of 60W “standard” lightbulb is a very new development that offers an alternative to the CFLs which are the commonly accepted alternative at the moment, so an interesting topic for a note. I’m assuming that the testing that the TSB will require for the contract will ensure the “quality” of this specific product!

      Regards, Barry.

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