LED v CFL bulbs

soft tone lamp iirc. icba to go look right now.

NT

That's because such commercial lighting is installed by lighting specialist contractors who can access sources of industrial and commercial lighting kit usually only directly available from the lighting manufacturers. The ceiling heights in downtown department stores are much higher than the 9 foot height ceilings typical of domestic housing which allows High Bay lighting practices to be applied which takes advantage of the narrower beam angles typical of LED based lighting.

The fluorescent tube wins out in a domestic kitchen by virtue of its 360 degree radiation pattern. In a high bay lighting situation in a factory or a large retail shed, fluorescent light fittings relied upon a trough reflector to obtain the beamed output now readily available with LED based lighting without resorting to the expense of such reflectors.

Harking back to my own kitchen light fitting, I'm pleased to report that the Helvar electronic ballast I'd ordered from Amazon arrived in the post this Monday morning. :-)

I've gotten as far as replacing the faulty ballast and testing the fitting with the two T8 tubes which *both* proved to be duds as far as the modern intelligent Helvar ballast was concerned. Oddly, it was the original tube that showed more lighting activity whilst the recently failed replacement only flashed briefly at switch on with the fitting only drawing less than a watt afterwards.

At that point, I was pretty certain, despite my previous thoughts on the matter, that I was now possessed of two failed tubes so nipped out to my very local Toolstation for yet another 36W 4ft T8 tube which confirmed the truth of the matter when I connected it up to the mains via my trusty analogue wattmeter. As expected, the first time run of the brand new tube started a bit on the slow side and took ten or twenty minutes to warm up and disperse the mercury vapour with an initial power draw of 28 watts eventually ramping up to and settling at 36.5 watts, about the same as what the basic "Dumb" Chinese unit[1] had drawn when I'd originally commissioned the fitting some two years ago.

I had to pull the PCB out of the rectangular plastic trunking of the cheap Chinese unit so as to cut the wires close to where they had been soldered onto the board in order to avoid having to patch them back to the length required to reconnect to the replacement ballast.

The tube connections were all at one end of the PCB and the wires for one of the tube ends had been routed internal to this plastic tube housing via the end cap hole adjacent to the mains input wiring hole. As a consequence of this inexplicable 'internal routing' a short section of insulation had been charred where it had been touching one of the pair of high voltage TO-220 plastic power transistors which problem I fixed using a short length of silicone rubber sleeving.

The Helvar unit uses push in connectors so I also had to strip and twist the stranded wire and tin the ends before I could reconnect the wires. By the time I'd finished bench testing, it was already too dark to be pulling the ground floor lighting fuse in the CU so I plan on finishing the job tomorrow in daylight hours.

I'm guessing the problem was simply down to a complete lack of any "Smarts" to protect itself from tube faults and vice versa. The only concession to safety being a small and still intact 2A 250v glass fuse soldered to the board. There was no sign of anything smarter than a transistor; it was all discrete components through and through (and lots of them!). I wouldn't have classed it as being 'cheap', just a little too primitively retro for its own good and for the sake of tube service life.

When CFLs first became available, the savings in running costs compared to tungsten filament lighting was the main selling point, especially true in locations such as hallways and landings where, for safety as much as convenience, it would be preferable to leave those lights switched on between dusk and bedtime.

Now that most domestic lighting is largely CFL based, if not already upgraded to LED, the savings aspect is rather more marginal leaving the "Instant On" characteristic of LED lamps as the main driver towards retiring existing fleets of CFLs in favour of relamping with marginally more efficient LEDs which use "wattage equivalency ratings" based on the higher efficiency American tungsten filament lamp standards rather than on the less efficient UK and European lamp standards.

The point I was making was that the 806 Lm reference would otherwise require a 72W rated 240v 1000 hour tungsten filament lamp. It actually works in our favour that the "60W tungsten filament" benchmark is based on the American 120v 750 hour lamp rather than our own feeble 240v 1000 hour rated lamps.

====snip====

The gas filled (rather than vacuum) tungsten filament lamps suffer very little drop off in Lumen output over their relatively short 750 and 1000 hour lifetimes, unlike fluorescent lamps with their 10000 to 16000 hour lifetimes to the 20% below design Lumen output where such lamps start off with a Lumen output from new of some 20% above "Design Lumens" which swiftly drops to "Design Lumens output" after just a few hundred hours.

I tried a 30W CFL in our hall pendant fitting a couple or three years ago. It was claimed to be equivalent to a 130W incandescent lamp AFAICR but my impression was that it seemed no brighter than a 100W incandescent lamp which makes me suspect that the wattage equivilency for CFLs is still based on the UK and European 240 and 220 volt 1000 hour lamps rather than the much brighter American 120v 750 hour lamps which is the benchmark for LED lamps.

Interestingly, this lamp, as far as I could estimate, died a sudden death at 6022 hours, suspiciously close to the guaranteed 6000 hour life rating, leading me to suspect it was based on a "Smart Ballast" which counted the run time hours in order to blow its safety fuse at the 6000 hour life rated point to prevent uneconomic running at below the 80% of design lumens limit. Not a bad thing IMHO but it would have been nice if they'd declared the existence of this energy saving feature up front.

Amen to that! We have a couple of 5 lamp chandeliers which we originally kitted out with 40W and 60W SES candle lamps which were replaced with 7 and 8 watt CFL "candle" lamps nearly a decade ago.

Just recently, within the past 12 months or so, I spotted the 330Lm 5W LED SES candle lamps in Poundland and took the opportunity to upgrade first one, then the other chandelier, both 'On The Cheap' and I've not had any regrets. Only one of the lamps suffered a premature failure which seemed to be a simple matter of a manufacturing defect which Poundland obligingly put right when I returned the faulty lamp on my next shopping trip into town.

The main benefit of improved LED lamp efficiency is less to do with reducing the running costs and more to do with reducing operating temperatures to fully realise the full lifetime rating in fittings that had been designed to handle the much higher temperatures of incandescent lamps rather than provide efficient cooling of temperature fragile LED lamps.

Example

Never really understood why makers need to lie about light output. Does it sell more to the gullible? It certainly annoys those who expect such claims to be true.

If they claimed the light output was say equivalent to the 60w (or whatever) GLS most would know, and it turned out to be better, who would complain?

Save that there are adults today who have never used ordinary, domestic incandescent lamp and wouldn't find that a useful benchmark.

In which case no real point in making the claim. Simply state the light output in a standard way.

I would guess it goes back to earlier days where there was no equal to the mid to higher wattage GLS lamps, and yet they felt the need to be able to offer an alternative.

If there is any element of "lying" in manufacturers' published specifications, it's normally the usual matter of "Lying by Ommission" as per the advertising industry's standard practice. In this case, the omission related to the specifics of filament voltage and design hours life rating used in America where the thicker shorter filaments can be run a little hotter (improving efficacy) and trading a bit of life (by running the filaments a touch hotter again to improve efficacy even further) against energy cost to optimise the overall running costs for domestic customers.

True enough, so my guess is they chose the most difficult to satisfy tungsten filament lamp benchmark, the American one, in order to keep the blurb about the 'advantages' printed on their product packaging regionless and nice and simple and to a minimum.

I was just pointing out to anyone who hadn't yet read the wikipedia articles on lamps and lighting technologies, the good news that this

I enjoy providing "Good News" so it's been by pleasure to point out the above 'factoid' about LED lamps. However, to summarise and keep it all in context, my next statement, comprising three items of "news", is more of a s*it sandwich.

The good news, as above, is that "You never had it so good." (in regard of light output). The "Bad News" is that heat kills LEDs, but the final "Good News" item is that the efficiency improvements of the latest LED lamps means you can now use an LED of equivalent light output of a 60 (or

They already do, using a Lumens output figure (typically 806 or 810 Lumens for the classic A bulb American 60W GLS lamp). Mentioning the tungsten filament lamp equivalent is their way of complying with discrimination laws in regard of "Ageism". :-)

I often get asked to replace one or more blown lamps when I visit my parents (they have 5 + 3 fittings in lounge and dining room) I noticed that the boxes for the 60W incandescent lamps this time *were* marked clearly in lumens.

Preferable to who? What safety?

What's wrong with a light switch in a convenient position to turn them on and off when needed?

You might trip over trying to find the lightswitch, especially if elderly or infirm.

Or more likely not bother turning the light on because it "seems" light enough even though it isn't quite.

SteveW

JOOI, can you recall the lumens figure on those 60W lamps (assuming that you're in the UK)? I'd expect a much lower figure than the 806/810 lumens figure typical of a "60W" LED lamp for 240v 1000 hour rated GLS lamps.

According to wikipedia (sorry about the line wrap) the lumens output figures for 120 and 230 volt 60W lamps are 850 and 730 respectively. However, I notice anomalous figures being shown for the 25W lamps (transposed column data?) so I wouldn't assume any accuracy, just 'Ball Park' figures.

Bear in mind that for a LED lamp to lay claim to being equivalent to a

It was the only way they could sell CFLs originally - by pretending that the feeble 40W ghastly greenish equivalent light output of a nominally

For some strange reason trading standards was never interested in it because it was problematic (ie expensive) to measure reliably.

It caught me out in the reverse direction when alarmed by the slow start time of a CFL in my parents bathroom I replaced it with an LED 60W lamp. The LED units produce the same light as a *real* 60W incandescent and are instant on which was far too bright. I had to fit a 40W instead!

The clue's in the email address :-P

They were not [marked as] rough service lamps just normal "old hat light bulbs" this is the type they'd bought, so 500 lm.

Different wattages from other photos from the same eBay seller

strangely the 40W clear golfball are 350 lm ...

because the claims made were true. CFL output was not compared with a standard filament lamp in the box claims.

NT