New style LED Light Bulb

[Mark]

All bar one of my expensive LED GU10s failed within two years. I've gone back to using halogens.

[Dave Plowman (News)]

That's been my experience with a variety of LEDs. Although I've not bought one recently.

I only really want low energy types where the lighting is on for long periods. Not much worried about a toilet or hallway etc where it isn't. But I'm not going to pay out for expensive lamps with a short life. Totally stupid.

[Mark]

+1, but these were for the kitchen/diner which are on for a long periods.

If they lasted as long as they claimed then I would have saved money overall. However they actually proved to be an expensive mistake.

[DerbyBorn]

Mark wrote in news: [e-mail]:

I have just had some LED Downlights fitted as part of an extension. Fantastic lighting - 7 year warranty. Halers H2 Pro. 8.5 watts.

[Huge]

If you do, can you share it with us?

[Dave Plowman (News)]

Good luck claiming for a failed one within that 7 years. Unless they're very under driven.

[DerbyBorn]

"Dave Plowman (News)" wrote in news: [e-mail]:

The driver is a separate module and the heat sinks are huge. Look them up on the website.

[Dave Plowman (News)]

So presumably a huge cost too.

[fred]

Still sounds like a pig in a dress to me, value wise.

Going back to your app, they are way dimmer than your existing lamps which you could still drop to 4 or 7W CFLs if lower light was acceptable and save a few quid.

[DerbyBorn]

"Dave Plowman (News)" wrote in news: [e-mail]:

[Dave Plowman (News)]

Plenty of hype there - they quote the light output as being 'comparable' to a 50watt GU10

A typical 50 watt GU10 gives 950 lumens. This warm white LED manages 467

[PeterC]

I've just bought 3 of Aldi's 3.5W golfball LED lamps and so far I'm impressed. The Anglepoise had a CFL (11W) in it of nominally 660 lumens; the LED is 220 lumens (so about the same on lumens/watt) but seems brighter and the Danglepoise now balances! The LED is 3000K and the CFL is a couple of years old and warm white, so not a fair comparison.

[Martin Brown]

250Lm is not bad for a 4W LED bulb 25W equivalent and I can vouch for Phillips "warm white" being indistinguishable from incandescents. I had a visitor fail to spot our kitchen uses mostly LEDs last weekend.

Not tried that one - it's only just announced. Not tried this one either but it is roughly the same spec 250Lm.

It is close to what you said you wanted. But a 9W CFL is usually more like 500Lm. I think you probably need something more like:

or

Illumination is strongest downwards and much weaker upwards (IOW the ceiling will appear much darker than with CFL or incandescent bulb).

How about adding a motion detector to them?

[Martin Brown]

Not sure omni directional is all that much use half a sphere will do me fine. I don't need the ceiling to be brilliantly lit. YMMV

The capacitors in the control electronics dry out and or slowly cook themselves. CFL and LED lamps in conventional enclosures tend to get too hot for the capacitors to have a long and healthy life. Also to get the best headline lumens they are run a bit close to the edge.

Purpose designed LED fixtures with proper heatsinks will last a long time but retrofit LED/CFL bulbs are always a design compromise.

The ones with the chunkiest heatsinks in fittings with nice airflow will last a good long time. Stick one inside a small glass ball diffuser with no airflow and it will die a quick horrible death.

[Dave Plowman (News)]

That proves nothing. Except about the visitor. ;-)

[whisky-dave]

DMPW/ref=pd_sim_light_8

"this equates to about 25 years if used for a few hours per day."

So in the real world pretty useless I'd say, for me anyway.

[Martin Brown]

How do you arrive at that conclusion?

The corresponding numbers for each technology and a nominal 60W bulb operated 24/7 based on manufacturers claimed MTBF are as follows:

Type Bulb Electricity/year Lifetime LED 10W £10 £11 50,000 hrs ? (unproven) CFL 12W £4 £13 8,000 hrs Halogen 42W £3 £46 2,000 hrs Basic 60W £0.5 £69 1,000 hrs (pessimistic)

Working on 0.12p/kW hr and ~9000hrs/year a 10W continuous load costs about £11 to run. One reason why reducing your home base load is good...

The corresponding costs to operate for 100,000 hours are therefore (number of lamps used) - ignores any installation costs

LED (2) £20 + £121 = £141 CFL (11) £44 + £141 = £185 Hal (50) £150 + £506 = £656 Bas (100) £50 + £759 = £809

In actual fact traditional filament bulbs will probably last a fair bit longer when left on continuously than makers normal use MTBF and solid state electronics may expire sooner. But the message is clear: If you can afford the up front costs of new high efficiency bulbs then you will win from the second year onwards even replacing CFLs with LED.

On worst case assumptions that solid state LED designs are only twice as reliable as the old CFLs rather than 6x longer lasting the LED lamp still wins out (just). The traditional bulbs might be dirt cheap but they are inefficient and waste a lot of their input power as heat.

If you have mains spikes then filament bulbs tend to blow and our old kitchen spotlamps tended to take the main lighting circuit down too.

I view all manufacturers MTBF claims with a big pinch of salt because I know first hand what slimy marketeers can do to real engineering data.

[Mike Barnes]

Martin Brown :

Blimey, that's cheap.

[Dave Liquorice]

Ball park. We have 15.06, 11.143, & 16.08/6.02 (+ 5% VAT). The 15.06 only has a 10p/day standing charge and is currently low (3 kWhr/day) use. The others are 22 and 18p/day but considerably higher use.

[Frank Erskine]

Still an awful lot dearer than 0.12p per kWh.