kitchen under cabinet lighting

[JohnW2]

To fit an LED costs the price of the LED and control gear so in the example I fitted which was 5 foot then cost £17 for the tube and should I have been buying the fitting then to get same light it would require a double fitting so total was around £36 compare with a single fluorescent with a HF ballast at around £18 it cost about double for original fitting to fit LED with the same lumen output i.e. compare like for like. ... At replacement time LED will cost £34 to replace and the fluorescent £3.4 actually likely fluorescent will cost less than that. Simply as with fluorescent your not replacing control gear and with LED you are.

OK, I now understand what you were saying. Thanks.

As I recently wrote, the one missing bit of that price comparison is the relative lifespans of fluorescent and LED tubes. In theory, LED tubes are meant to have a lifespan of around 40,000 hours, whereas fluorescent tubes usually claim lifetimes around a quarter to a third of that - so, in theory, one would have to replace fluorescent tubes three to four times more often than LED ones, thereby decreasing the (very) long-term price difference.

Mind you, this is all a bit hypothetical. At, say, a couple of hours use per day, 40,000 hours amounts to about 55 years, so I doubt that (m)any of us would be around to worry about replacement cost if it really lasted that long! ... and, of course, available technologies for lighting will almost certainly have changed dramatically long before 55 years has passed!

Kind Regards, John

 

[ericmark]

I looked at this tube rated at 30,000 hours then looked this tube rated at 20,000 hours then at this site on electronic ballasts the latter claims tube life is doubled so it would seem tube life with an electronic ballast is at least as good as with a LED.

The 58W tube says 5200 lumen the information I have found to date says the output increases by using an electronic ballast however it varies so how much better is it seems open for debate but even without accounting for the extra light we have 89.7 lumen v 100 lumen so a 24 watt fluorescent tube is equal to a 27 watt fluorescent tube not 36 watt as stated in the advert.

In other words there is very little in the performance of a fluorescent tube with an electronic ballast to a LED tube. The big difference is the LED tube gives out a lot less light. To me this is a con, you see a LED tube rated 24W which replaces a fluorescent rated 58W and one says what a saving, however if one was to say I need two LED tubes at 24W each so I need to change to a double fitting to get the same light output then the advantage quickly fades away.

The 24W rating is when measured at the tube, the tube will work with a reduced voltage so one can leave the ballast in place (magnetic type) and just change the starter, however if you tried to change back without renewing the starter it would blow the heaters, and also you are losing energy heating up the ballast, remove the ballast and then put a fluorescent back in it's anyone's guess as to what will happen with no current limiter, but that is what is required to get full 100 lumen per watt. I wired mine with power just to one end, that is also a problem as fit the tube wrong way around and you have a direct short.

In my case I could not get good access to the fitting and the whole reason for fitting LED was the 65W tubes are no longer made and it was either remove the fitting and change the ballast or fit a LED and rewire fitting in place which I could do without moving all my wife's craft rubbish (hope she never reads this) piled up under the light. So it was worth the £17 not to have all the work, and I had not realised about the reduction in lumen output until after fitting. As luck has it 2400 lumen is enough, I would have been rather upset had that not been the case.

It was the fitting of this lamp which caused me to look at fluorescent v LED and I came to conclusion only with the folded fluorescent used to emulate tungsten bulbs was fitting an LED instead of a fluorescent worth while. Where the original was a fluorescent tube then better to keep a fluorescent tube, may be fit an electronic ballast, but stay with fluorescent.

 

[JohnW2]

In other words there is very little in the performance of a fluorescent tube with an electronic ballast to a LED tube. The big difference is the LED tube gives out a lot less light. To me this is a con, you see a LED tube rated 24W which replaces a fluorescent rated 58W and one says what a saving, however if one was to say I need two LED tubes at 24W each so I need to change to a double fitting to get the same light output then the advantage quickly fades away.

It does seem a little odd. I would imagine that they could have produced an LED tube with similar light output to a fluorescent of the same length, so I wonder why they didn't (which is what they have attempted to do with most other LEDs). Did they perhaps feel that many people were using fluorescents which were 'unnecessarily bright', and that the lower output LED ones would usually be adequate for them? Any other ideas?

Kind Regards, John

 

[ericmark]

Cost it seems you can get LED tubes which give out more light but the cost is much higher. My son it seems was also sucked in a his work, he also swapped an area from fluorescent to LED thinking he was saving money only to have to revert back as output was not good enough. It is however very off putting as the colour temperature is often higher than the fluorescent so one thinks they are brighter, only when you try reading do you realise the light level is lower and you need a reading lamp.

I noticed it with my camera with 8W CFL I could take photos in the room without flash, using 3W LED the rooms seems brighter but I now need flash to take photos, plus need reading lamps. It is a big con, the LED is no where near as good as we first think, specially when you look at lumen per watt, although LED lamps can give 100 lumen per watt some are down to 40 lumen per watt, one has to be careful, most of my bulbs are around the 75 lumen per watt mark, only the tube actually hits the 100 lumen per watt.

Most of the specials for caravans rated DC 10 ~ 36 volt also give the full 100 lumen per watt so it's nothing to do with shape or physical size it all down to the built in driver those for caravans have better quality drivers built in.

 

[JohnW2]

Most of the specials for caravans rated DC 10 ~ 36 volt also give the full 100 lumen per watt so it's nothing to do with shape or physical size it all down to the built in driver those for caravans have better quality drivers built in.

As you imply, LEDs themselves are very efficient (at producing light), and it's theoretically possible to make pretty efficient drivers for them.

However, if the cost of producing a "very efficient driver" is high, then it may make sense to forget about 'efficiency' and get an LED unit which produces the required amount of light, no matter what that means in terms of (overall) 'lumens per watt'. In other words, it would not necessarily be worthwhile to pay a fortune just to get a gratifyingly high 'lumens per watt' figures!

Don't forget that we are talking about lamps which may well only cost a pound or three per year to run (with 'normal usage'), so there is a definite limit to how much it's worth paying in initial capital cost in order to reduce that figure!

Kind Regards, John

 

[ih]

thank you very much 333rocky333 & ericmark all very valuable advise.fluorescent relamp is the way and 865colour code . also thanking all others for input.

 

[JohnW2]

....fluorescent relamp is the way and 865colour code . also thanking all others for input.

You presumably realise that 865 (6500°) is a very different colour from your current 535 (3500°)?

Kind Regards, John

 

[ericmark]

Most of the specials for caravans rated DC 10 ~ 36 volt also give the full 100 lumen per watt so it's nothing to do with shape or physical size it all down to the built in driver those for caravans have better quality drivers built in.

As you imply, LEDs themselves are very efficient (at producing light), and it's theoretically possible to make pretty efficient drivers for them.

However, if the cost of producing a "very efficient driver" is high, then it may make sense to forget about 'efficiency' and get an LED unit which produces the required amount of light, no matter what that means in terms of (overall) 'lumens per watt'. In other words, it would not necessarily be worthwhile to pay a fortune just to get a gratifyingly high 'lumens per watt' figures!

Don't forget that we are talking about lamps which may well only cost a pound or three per year to run (with 'normal usage'), so there is a definite limit to how much it's worth paying in initial capital cost in order to reduce that figure!

Kind Regards, John

Yes very true and I would guess that's why a looking at bulbs I have bought the 2W GU10 was 60 lumen per watt, and as the watts increases so the lumen per watt also seems to increase. E27 spot at 10W was 86 lumen per watt, and best was the replacement tube at 100 lumen per watt.

 

[ih]

Hi
John yes she wanted daylight so 865! I will appreciate if you can help to confirm if installed ballast
Are magnetic or electronic fyi they have individual starters.( google says electronic donot use starters)
Thanking in advance.

 

[JohnW2]

Yes very true and I would guess that's why a looking at bulbs I have bought the 2W GU10 was 60 lumen per watt, and as the watts increases so the lumen per watt also seems to increase.

Taking that example, even if the 2W one were "120 lumens per watt", that would probably save you under £1 per year in running costs (with 'normal usage') - so how much extra would (or should!) you be prepared to pay for such a "high-lumen-per-watt" lamp, if one existed?

Kind Regards, John

 

[Iggifer]

I would imagine that they could have produced an LED tube with similar light output to a fluorescent of the same length, so I wonder why they didn't (which is what they have attempted to do with most other LEDs). Did they perhaps feel that many people were using fluorescents which were 'unnecessarily bright', and that the lower output LED ones would usually be adequate for them? Any other ideas?

I suspect it also has something to do with the 360° nature of light output from a fluorescent tube. I have yet to see an LED tube that has more than 180°, and in reality, it's just a flat strip of LEDs inside a tube.

If they made the backside the same as the other side, then perhaps it would be nearly as bright. But fluorescents are already pretty good, if you did that, I think you'd be getting close to a similar wattage anyway

 

[JohnW2]

I suspect it also has something to do with the 360° nature of light output from a fluorescent tube. I have yet to see an LED tube that has more than 180°, and in reality, it's just a flat strip of LEDs inside a tube. ... If they made the backside the same as the other side, then perhaps it would be nearly as bright. But fluorescents are already pretty good, if you did that, I think you'd be getting close to a similar wattage anyway

Maybe, but I think one can probably argue that either way, depending upon how reflective the surface behind the tube is - i.e. if that surface were not a very efficient reflector, you might get more light by having all the light production concentrated on the 'front' side of the tube.

Kind Regards, John

 

[Iggifer]

Perhaps. But gloss white is a fairly good reflector of light anyway. And in under cupboard lights in particular, only about 30% of the tube backs onto the housing. The other 70% is shining out into free air

 

[JohnW2]

Perhaps. But gloss white is a fairly good reflector of light anyway. And in under cupboard lights in particular, only about 30% of the tube backs onto the housing. The other 70% is shining out into free air

I'm not quite sure 'which way' you are aguing In the 'under cupboard' situation, I would have thought that what mattered most was light radiated directly at the work surface, rather than reflected light - in which case might not the LED tube, with all it's light coming from one side, be expected to be more efficient?

Kind Regards, John

 

[Iggifer]

Perhaps. But gloss white is a fairly good reflector of light anyway. And in under cupboard lights in particular, only about 30% of the tube backs onto the housing. The other 70% is shining out into free air

I'm not quite sure 'which way' you are aguing In the 'under cupboard' situation, I would have thought that what mattered most was light radiated directly at the work surface, rather than reflected light - in which case might not the LED tube, with all it's light coming from one side, be expected to be more efficient?

Maybe. But I'm of the opinion that it's the lack of this extra (non-directional) light that causes LED tubes to be less bright. Yes, they direct the light downwards, but you don't get the light reflecting off the underside of the cabinets, walls etc. as you would with a fluorescent.

I generally am a big advocate of LED lighting, but I don't think there's a good enough LED tube yet to replace them. It's not such a big deal with UC lighting. Like I say, a bit of decent LED tape does the job a lot of the time.