Are energy-saving light bulbs now a thing of the past already?

[ChrisK]

23w is still available in the usual stores/supermarkets. I think the problem is that that is the largest size that can be sold without power factor correction which puts the cost up to more specialist levels.

IME there were a number of early failures of CFLs, typical bathtub curve, but since then they have proved reliable. I've been retiring them because they do get gradually dimmer without dying but have now gone over to LEDs for the open fittings. Instant on and much better colour rendering. I find the CFLs too red at the compulsory 2700K.

Like many, I've still got a large box of the freebie linear ones which never seemed to fit any light fittings unlike the later more compact spiral types.

ChrisK

[cl]

Because the difference isn't worth bothering about when compared with one's energy costs overall maybe?

So I spend £100 on energy saving bulbs and save say, half that much, over their lifetime. Wow, I've saved £20/year or maybe a bit more.

Life's too short.

[Tim Streater]

That is a problem, and is a problem also with those shitty daytime running lights that seem to be mandated now. We didn't put LEDs in the bathroom for just this reason, but stuck with a fitting with one of those 28W D-shaped fluorescents.

What you prolly need is a disperser filter in front of the lamp. We have LED frosted candle blubs in the dinnning room and they work fine - no arc eye from them.

[Tim Streater]

I'd rather not, thanks.

[Huge]

Virtually every room light in my house has a dimmer.

[harryagain]

Total drivel.

[Johny B Good]

Interesting to note that what they thought of as "High Efficiency" (a mere 71L/W) back in 2012. Oh how swiftly the LED technology of yesteryear dates[1]. :-)

We can reasonably expect to see LEDs with 3 times greater efficiencies in another 12 months or so ( 81L/W or better 'Bulbs' are already on the shop shelves).

[1] The manufacturers, notably Cree, have already tested lab examples of 303L/W lamps just over a year ago. Both they and Philips have been quoted as claiming a Lab to shelf lead time of 18 to 24 months.

The theoretical limit, afaicr, is just over the 400L/W mark and that Cree lab example is pretty close to that limit so, once the 200 to 300 L/W lamps get to market, there won't be any repeating of the 3 fold improvement over the past two or three years since those "High Efficiency" PLs were first advertised. In fact any further efficiency improvements are unlikely to better another 25% _ever_

[Martin Brown]

One arc is, but if the plasma from that arc bridges the feed wires to the filament then you get a huge pulse of current. It is most often a problem with spotlights where the rising hot plasma from the initial small arc almost invariably does short out the mains for a moment.

Filament spotlamps are generally fused for this reason but a mains circuit breaker is often quicker and takes the lighting circuit out. LED spotlamps are much better in this regard.

The starter uses the ballast to create the initial ionisation but once it is conducting a gas discharge tube has a negative effective dynamic resistance with current rising with decreasing voltage and it would self destruct if there wasn't a ballast to keep the current within safe working limits.

[MM]

What did the 4W LEDs cost each? So's I get some kind of ballpark here.

Currently the kitchen, landing, bathroom, hall and downstairs loo have GU10s with associated transformers. There are 28 of 'em.

- How much (rough estimate) to replace all with LEDs?

- Do I retain the transformers, or does LED use a different technology?

- Will the GU10 sockets take LEDs?

- What would be the cost saving in terms of electricity over a year?

MM

[MM]

But CFL bulbs don't last anything like as long as people said they would back when the promotions were on. I reckon that was about 6, maybe 7, years ago and I've used ALL the dozen bulbs I bought back then at 50p each. So most didn't last 6 years, and this is in bedrooms that hardly get used.

MM

[MM]

Yeah, I tend to agree. Bit like weighing a portion of spaghetti before cooking so as to save 6 calories. Like, I go and put an "old-fashioned" 60W filament bulb in my bedroom ceiling pendant and lo! I can read my bedtime book again!

MM

[MM]

Why on earth?

I've NEVER had a dimmer. What am I missing?

MM

[Martin Brown]

Depends a lot on the light shade, the model of LED lamp and the room.

I put my first one ever in my parents bathroom because I didn't like the

*very* long time the aging and dim "60W" CFL took to come up to an acceptable brightness. I didn't like the idea of them stumbling about in the semi-dark.

I got a 60W LED warm white lamp and the light in the small space was absolutely dazzling reflected off the tiled walls not direct. I got a nominally 35W equivalent and it was perfect with instant on light.

LED lamps are more directional with most light going in the lower half sphere away from the socket and comparatively little sideways. This can make the walls and ceiling look dark in some rooms depending on the nature of the lamp shade. Just underneath the fixture is over lit.

LED spotlamps are if anything slightly too directional now.

[Tim Streater]

Actually 3.3W, it turns out, in Dec 2012. Cost £8.50 each. Plug in replacements for existing GU10 halogens.

[Huge]

Because that's what we prefer.

[Dave Plowman (News)]

Really? Not got that much experience of LEDs yet. Waiting for them to produce a decent colour spectrum (close to halogen which I like) which they might well one day.

However, I did use an very expensive LED in one fitting where it was suitable, and it blew up in the most spectacular way after a shorter time than a tungsten would have lasted. And tripped the MCB.

[Dave Plowman (News)]

I have found they give their rated life when used outdoors where they are kept cool.

Why use them in a little used area? That generally means they are only on for a short time where the light output can be low. And any savings in energy used proportionately less.

The obvious first place to first fit them is where lights are most used.

[Dave Plowman (News)]

A dimmer allows you to set the 'mood' of the room. Full brightness for working - hoovering etc - and reduced for relaxing.

[Dave Plowman (News)]

Why change from tungsten in the first place, then?

[Martin Brown]

Indeed it only makes sense to swap them in as and when the existing ones fail which tends to be in the most often used positions.

Also worth doing for really awkward to reach landing lights that are a PITA to reach to change the light bulb.