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Green Building Bible, Fourth Edition
Green Building Bible, fourth edition (both books)
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    • CommentAuthorRex
    • CommentTimeMay 11th 2020 edited
     
    What ho all self isolators,

    I'm confused about the benefits of LED, particularity GU10. The first batch in the kitchen, all SMD, OK but not so bright and then, way before their anticipated 30,000 hour life span, they started to fail.

    Buying replacements would probably be pretty obvious different to the non-blown one, so went with some brighter, COB lamps, probably pre-virus from China.

    They are rubbish!!!! What a surprise. Had them installed less than five months and to date, had to replace two. Tonight, another two have gone.

    They may be energy saving but are definitely more expensive with all the failures.

    Is there a good brand at a reasonable price? What is it? Do any shops retailers some kind of guarantee and if so, is it worth buying from them? Given taht they probably all come from China, can one trust any of the brands, no matter how well known the name?

    Thanks and toodle pip

    Rex
    •  
      CommentAuthordjh
    • CommentTimeMay 11th 2020
     
    I bought a variety of different brands before then buying a batch of 50 for our house. They're all Crompton and none have failed so far after five years. Oh, one of some different brand in an IP65 sealed enclosure outside has failed twice - it's on about 8 hours a night. Next time I'll try to find a Crompton.
    • CommentAuthorSilky
    • CommentTimeMay 11th 2020
     
    had similar experience with replacing regular size bulbs, although screw in ( on the continent ), eventually worked out the weak point is the bulb holder, if these are old and/or trap moisture bulbs fail. I'm sorting of testing as I go along so I replaced one ceiling lamp with the cheapest Phillips fixed LED lamp (i.e. no bulb to screw in), this has worked flawlessly for a couple of years on the same circuit where bulbs failed often, another has also stop failing since I just left off the cover, another I fixed by replacing the pendant. Was so annoyed after having numerous expensive bulbs die after a few months and I tried Osram, Phillips, Ikea etc.. so my conclusion is to go for 'native' LED lights rather than 'LED in a bulb' lights.
    •  
      CommentAuthordjh
    • CommentTimeMay 11th 2020
     
    I intend to never buy a luminaire where it's not possible to replace the lamp. Indeed I'd outlaw them if I could.
    • CommentAuthorSilky
    • CommentTimeMay 11th 2020
     
    just to clarify, you can actually replace the LED elements in some lights ( I looked into it briefly but no expert.. ) and if they work correctly then that should only be after 15 - 25 years, I'm just trying to say that the metal bayonet or screw-in connection is the weak point in the design, especially outdoors or in kitchens or bathrooms, so if you can eliminate that you will hopefully get the reliability, otherwise, make sure light fittings are absolutely top quality and the bulb connection is in a humidity proof enclosure
    • CommentAuthorRex
    • CommentTimeMay 11th 2020
     
    The SMD bulbs seemed OK and the only reason I did not get more, is that a few new ones would look different to the existing, Kelvin and or lumens.

    I just don't now where the alleged 30,000+ hours sort of figure comes from. May be in China they run them at around 50V and they last forever?
  1.  
    We've had 4 Philips led bulbs on for the last 30,660 hours and still running strong. Probably been turned off for a day tops in that time
  2.  
    IME the LED bit does last forever, but the tiny power supply electronics board overheats and cooks, especially when squished into the top of a GU10 package.
    If you can run low voltage bulbs with a remotely mounted power supply then they last much longer.
    • CommentAuthorwookey
    • CommentTimeMay 12th 2020 edited
     
    Mains-power LED bulbs are a shitty idea. Having a (really cheap) LED driver/mains converter in every bulb is idiotic and unreliable.

    Get one driver unit to power each independently-switchable set of lighting in a room - could be one large luninaire, or several smaller ones. They can be current or voltage driven (voltage is much more widely available, current is more efficient).

    Then what you are putting on the ceiling is just bare LEDs, which makes them cheap and incredibly reliable, and there is one driver unit somewhere. Not expensive, but maybe don't buy the cheapest possible one you can find. £10 rather than £2 sort of thing.

    Back in 2010 I used to make my own LED units as it was hard to buy bare LED luinaires (http://wookware.org/DIY/LEDlighting.html), but it's easier now. I've mostly been using Ledkia's flush-mount devices (£3-6 each) square or round, and none of mine have failed after a few years. They look a bit nicer than my DIY ones too. Can be current or voltage-driven (but designed to be used with a 12V supply). They are strip-based internally so not quite as efficient as a totally bare LED, but still pretty good. I don't use the cheap and nasty drivers they come with and get one decent one for the room (usually from leds.de but they are widely available now - screwfix have them) . It would be great to find a source of these lamps that wasn't sending a useless driver unit with each fixture.

    https://www.ledkia.com/uk/11-buy-downlight-led
    • CommentAuthorLF
    • CommentTimeMay 12th 2020
     
    Thank you wookey this looks really good.

    Still feel angry about the fact the very hot halogen downlighters were on sale despite the fact they cut a hole in your fire rated plasterboard and let noise through to different rooms. Then came fire hoods etc. I would not fit them in a new installation which is not what Rex is asking but I needed a moan.

    Mine were small MR11 which were hard to find as LED and I had many experimental ones over the years.
    I use a separate LED driver for them and they must have been in 5 years, there were some dodgy cheapo ones and definitely not something to skimp on. Care that it is LED driver (DC) not AC.

    Our CWatters always posts good stuff on lighting and is worth checking out.

    I suffered a premature failure on a luminair with built in driver and agree with djh they are a pain.
    I think it was the driver that failed on this £20 simple plastic domed unit from Screwfix.
    •  
      CommentAuthordjh
    • CommentTimeMay 12th 2020
     
    I should probably add that all my GU10s are in exposed surface mounts, not recessed into the ceiling, apart from wetrooms where they're in IP44 cans, but still surface mount. So they should run reasonably cool.
    • CommentAuthorMike1
    • CommentTimeMay 12th 2020 edited
     
    I've also used Crompton for regular BC lamp replacements, plus LED strips and fluorescent tube replacements without problem.

    However the 12v MR16s and 240v GU10s don't tend to last more than a couple of years. LEDs may be more efficient than traditional builds, however they do still put out a lot of heat, and it's difficult to disperse that in an MR16 / GU10 package - there just isn't much space for a decent heat sink. The electronics that drive them are also often of poor quality (sometimes dangerously so - for example https://www.youtube.com/watch?v=keaE7QTKTYE), so best to stick to a well recognised brand.
    • CommentAuthorlineweight
    • CommentTimeMay 12th 2020
     
    I think it's a bit of a problem with LEDs - in that the light they produce can be quite different between manufacturers even if they have the same colour temp rating and so on. And this difference is often visible if you have to replace one out of a bunch of matching ones. Not really somthing that used to be such a problem with old skool lamps.

    Of the LED lights I have, some are striplights running off 12v drivers, some are GU10 type things in regular mains voltage holders. In retrospect maybe it would have been better to have them run on 12v too.

    I've had problems with 12v transformers though, although that may be my fault for buying some of them secondhand or cheap. The main issue is that they can start to produce a very irritating high pitch whine. I think this is sometimes called "coil whine". I assume that buying better brands has a better chance of avoiding this. They can be quite expensive though, if you are after something more than about 120W.
  3.  
    Posted By: djhI intend to never buy a luminaire where it's not possible to replace the lamp. Indeed I'd outlaw them if I could.


    I've had a stack of of GU10 bulbs fail in the 5 years that I've been in the new house but have yet to have any luminaire with a non-replaceable bulb fail.

    LED bulbs have to pack the LEDs and the driver into a tiny space of a fixed dimension in a shape that does't promote heat loss. they get hot and fail. a proper driver separated from an LED with decent heatsink has a much better chance of actually delivering design life.
    • CommentAuthorXT600
    • CommentTimeMay 12th 2020
     
    Do Crompton do a dimmable wide beam gu10? I suspect not. I've experimented with lots of gu10 s but have only found one brand which do the 110 degree beam angle on a dimmable. They perform really well, but only for a month or two!
    • CommentAuthorRex
    • CommentTimeMay 12th 2020
     
    Thanks for all the interesting comments.

    I do have a number of E27 LED bulbs and they really don't have the same problem the the GU10 bulbs do.

    But I will also admit that at the time of build, I was recommended to install halogen and later, when LED came down in price, fit the GU10 replacements. So my bulbs have the electronics in the bulb.

    What is the solution. Can I refit the GU10 bits with something that will allow the LED to not blow?
    •  
      CommentAuthordjh
    • CommentTimeMay 13th 2020
     
    Posted By: lineweightI think it's a bit of a problem with LEDs - in that the light they produce can be quite different between manufacturers even if they have the same colour temp rating and so on. And this difference is often visible if you have to replace one out of a bunch of matching ones.

    Yes, when I bought my initial one-of-every-type batch I was quite surprised at how different the light from each was and in particular how many had alternate blue and yellow fringes in the light cone. That was one reason I went for a well-established brand.

    Posted By: XT600Do Crompton do a dimmable wide beam gu10?

    Dunno, sorry. I don't believe in dimmables and didn't care about beam width very much.

    It sounds to me that the metal shell of the lamps rather than plastic, as well as exposed fittings might be quite important in longevity. I see that Crompton give theirs a four-year guarantee.
    • CommentAuthortony
    • CommentTimeMay 13th 2020
     
    Off beam ball coming

    When energy savings are considered it is still done incorrectly

    LED bulbs save electricity yes but the room or building still has the same energy demand as it did when the precious luminary was adding it full wattage as heat into the room so savings are not as good as claimed as the watts or kWh saved will have to be made up by the heating system so although money will be saved no energy is saved During the heating season which will be a few days longer each end too.

    I like them and use them though
  4.  
    Surey your excellent insulation means your house's heating season, is much shorter than its lighting season, Tony?

    The issue with the GU10s is they are designed for shop displays, so the light is reflected downwards but the heat is sent upward, where it is no use.

    If the GU10 is recessed in the ceiling then the heat goes straight into the loft, along with a big draught of warmed air.
    • CommentAuthortony
    • CommentTimeMay 13th 2020
     
    LOL, that is a function of recessed down lighters, not of LED’s

    I don’t have a heating season but have started shading my windows to mitigate potential overheating
    • CommentAuthorRex
    • CommentTimeMay 13th 2020
     
    Seems to me it is a minefield ( just like car insurance!)

    When I built my house around 15 years ago, LED downlight modules where very expensive, so I fitted halogen and the sparkie told me that I could change to LED bulbs at any time. As the halogens blew, so I changed them all to SMD LED. With the exception of the kitchen 8, they are still the original LED bulbs and seem to have no problems.

    But the kitchen ones get the most use. I understand that the internal bulb electronics don't like the heat, but what can I do? I may be prepared to change the whole fitting, but I have no idea what I am looking for. A google search and both halogen and LED gu10 fittings look pretty much the same to me. If the LED drivers (or whatever is needed) are in the fitting rather than the bulb, and hence the bulb does not get so hot, does that imply that any LED bulb (rated up to 240v) will fit into a specific LED fitting?

    And what is this business of LED drivers?

    Thanks
    • CommentAuthorMike1
    • CommentTimeMay 13th 2020 edited
     
    Posted By: RexWhat is the solution.

    I'd replace them them with mini LED panels such as those suggested by wookey.

    Those that I've seen are lit by high-density LED strip around the perimeter - so they're less subject to overheating and the strip should be fairly easily replaceable should it stop working - with an external driver. I guess that the ultra-slim ones will use a high-density untra-slim LED tape, so maybe that's not quite so easily obtained for replacement - maybe someone knows?

    Subject to the driver, they can be dimmed, and some have multi-colour LED strip so that, with the right controller, the colour can be changed.

    Posted By: Rexwhat is this business of LED drivers?

    They're the electronics that provides the correct DC voltage and keeps the supply stable to feed and protect the LEDS (and sometimes to enable dimming / colour change).

    Separate drivers are readily replaceable if they pack up, provided they're in an accessible location, as they should be. Their quality can vary significantly though, so buying cheap can be a mistake.

    Posted By: tonythe room or building still has the same energy demand as it did when the precious luminary was adding its full wattage as heat into the room

    However in summer traditional bulbs will be contributing more to overheating, or at least heating the air unnecessarily.
    • CommentAuthorRex
    • CommentTimeMay 13th 2020 edited
     
    Just been looking at

    https://www.ledkia.com/uk/buy-placas-downlight-led/63087-round-6w-slim-led-panel.html. Would have to enlarge the current plasterboard holes but that would not be a problem.

    Wookey said "I've mostly been using Ledkia's flush-mount devices (£3-6 each) square or round, and none of mine have failed after a few years. They look a bit nicer than my DIY ones too. Can be current or voltage-driven (but designed to be used with a 12V supply). They are strip-based internally so not quite as efficient as a totally bare LED, but still pretty good. I don't use the cheap and nasty drivers they come with and get one decent one for the room (usually from leds.de but they are widely available now - screwfix have them) . It would be great to find a source of these lamps that wasn't sending a useless driver unit with each fixture."

    What is current or voltage driven mean? The data sheet on the above link says 220 240 v so what is the 12V Wookey mentions? Strip based internally? Drivers from Screwfix? Does that imply I have to fit another component and if so, is it for each light?

    I know there will be the comment that if I don't understand, I should not be doing it. I am quite able to install, but my LED experience is at the moment, only exchanging halogens or CFL for LED, just screwing them in.
    • CommentAuthorEd Davies
    • CommentTimeMay 14th 2020
     
    Posted By: RexWhat is current or voltage driven mean?


    LEDs are intrinsically current-driven devices. That is, (approximately) for a given amount of output light you want to feed them a specific current. Different devices and the same device at different temperatures will have slightly different forward voltages for that particular current. For small red LEDs the forward voltage will typically be somewhere around 2.something volts but for white LEDs it'll be more like 3.6 V.

    If you feed a bare LED a fixed voltage then, as the temperature changes, the current through it will vary markedly. A particular voltage could result in a small current (and so relatively dim output) at one temperature. As the device warms up its forward voltage will drop. With a fixed-voltage source the current will therefore increase resulting in more warming so a higher current so more warming until, if the voltage source can provide sufficient current, the LED goes pop.

    Therefore all LEDs need some mechanism to keep the current relatively constant. It can be a constant-current power supply in which case things can be quite efficient. At the other extreme it can be a simple resistor in series with the LED so that, as the current increases, the voltage drop across the resistor also increases moderating the current increase. Of course the voltage drop across the resistor will result in power being wasted in it making the overall system less efficient.

    Current-driven LEDs are just bare devices which expect an external box to feed them the right current. By contrast, voltage-driven ones have internal resistors (or slightly cleverer circuits) to control their forward currents sufficiently.

    Either will probably have chains of multiple LEDs in series so the input voltage will be higher than the forward voltage of a single LED.

    They might also have multiple chains in parallel. For current-driven devices these will need resistors, or something, to keep the currents in the chains balanced but these will be relatively small.
    • CommentAuthorRex
    • CommentTimeMay 14th 2020
     
    Thanks for the explanation; not sure I understand but that is because I have never been able to get my head around voltage / current / amp / watts and their respective interaction.

    I am after a simple replacement for LED that don't last the specified 30k hours. Seems that halogen replacement LEDs are not the way to go, so guess it is to replace all the ceiling fittings with something that includes a ceiling driver?

    Or just buy good quality replacements (Phillips) and hope that they are manufactured in a 'better' Chinese factory.
    • CommentAuthorphiledge
    • CommentTimeMay 14th 2020
     
    To understand volts, current etc think of it as water in a hose pipe-
    Volts is the pressure making the water move along the pipe
    Current is the water flow rate
    Amps(amperes) is the units of current equivalent to litres per second/minute in water terms
    Watts is the energy contained in the flowing water so a firemans hose that will knock you over has more energy than a typical garden hose

    Hope that helps
  5.  
    I may as well add in my 2 penn'orth.
    I've been putting in LEDs almost since they started - I did the sums and it is a no brainer.
    In my kitchen, I replaced 12 x 35W GU10s with 12 x 3W LED GU10s and as its a kithcen, centre of the house and all that, the lights are on a lot. Each bulb pays back in less than a year. And on average last a lot longer
    But, they sure as heck dont last 20,000 hours! I've found that you get the classic bathtub curve of reliability. Quite a few fail early, and then they last. TP24 were very good.
    As others have pointed out, the really frustrating thing is the difference between manufacturer. My kithcen has 2 x 6 lamp fittings, and I do like to have them match. And it is a nightmare.

    Bathroom is 24V, they last much better, but it is an old school transformer, and it plays havoc with the DAB radio signal - I mean, kills it stone dead. Fortunately, they arent on that much.

    And finally, the heating/energy bills thing is as a bit of a red herring
    1) Most houses are gas heating. Elecccy is 3 - 4 times the price of Gas.
    2) If you really want to heat your rooms with heaters fitted on the ceiling, be my guest.
    3) Heating and lighting demands arent that well matched. Some, yes, in total, not really.
    • CommentAuthortony
    • CommentTimeMay 14th 2020
     
    Still begs the question about them being miscalled energy saving lightbulbs.

    Then the real cost of gas is the cost of making it and putting it back in the ground, not the money you pay for it
    • CommentAuthorwookey
    • CommentTimeMay 15th 2020 edited
     
    Lineweight said, referring to drivers:
    if you are after something more than about 120W


    Given that a room typically needs about 15W of LED to light it, what sort of rooms (or astonishingly inefficient LEDs/luminaires) have you got where you need a 120W driver?

    You can sometimes fix the whine by opening it up and gooping up the inductors better. The inductors sometimes run at audible frequencies and if they can physically move you can hear this. Glue/goop is normally applied to stop this. I'm not sure what the best material to use is. Silicone is probably quite a good bet.


    Mike1 said:
    Those that I've seen are lit by high-density LED strip around the perimeter

    Right - that's how the ledkia ones work. The white light area is edge-lit by a standard LED strip so should be fairly easy to fettle if you can find the right lumens/metre (I guess they are about 6W over 25cm or 3W over 14cm sort of thing). The strip is heat-sunk on the metal frame.

    Rex said:
    The data sheet on the above link says 220 240 v so what is the 12V Wookey mentions? Strip based internally? Drivers from Screwfix? Does that imply I have to fit another component and if so, is it for each light?


    The site says that because every lamp is supplied with a little 3W/6W mains-to-12V LED driver. So you can just put them in like that, attached to the mains supply, one driver per lamp.

    But I wouldn't particularly recommend it. You don't get a high quality driver for ~£2 (Although the efficiency on the ones I measured wasn't too bad actually). The lamp itself expects to be driven by 12V or 350mA (3W lamps), 700mA (6W lamps). Because it's a strip with resistors on it there is no significant efficiency difference in this case. Using the supplied drivers may well work better than GU10s with built-in drivers, because the driver lives 20cm away on a little pigtail it is not overheated. And in that case you use one per light, nothing else to buy except maybe some WAGO blocks for connecting things up.

    I get a decent separate driver with sufficient wattage to run all the lights in the room that I want to use together (e.g 4 x 3W or 2 x 6W), then run them all with that (wired in paralllel for a 12V CV driver, series for a 350mA or 700mA CC driver). If electrics is all a bit foreign to you, stick with the 12V (constant voltage, parallel wiring) - it's simpler.

    Oh and Tony, You've been making this silly point about 'energy saving lightbulbs' for years. It's stupid, they do save energy, lots of it. Dimengineer explained why. Our electricity bill dropped by nearly 1/3rd when we fitted LED in main rooms (switching from CFLs). The lights are on about 20 times longer than the woodburner through the year, and at least 2/3rds of the year the lights are used but the heating isn't. The substitution effect is somewhere between small and negligible.
    • CommentAuthorLF
    • CommentTimeMay 15th 2020
     
    I get Tony's point that wasted energy into lighting is mainly heat and it reduces the heating load.
    Unless you are heating on electric with no heat pump advantage then more electricity is used overall and this will have higher CO2 emissions than running LED bulbs with lower watts.

    Lights on in middle of winter with no/limited wind then lecky will come from gas or even worse coal. So CO2 emissions are more than 2.5 times for the lecky used for the heat from lights at these times, compared to say gas boiler producing the heat.

    If everyone on LEDS then more of the lecky will come from low CO2 sources as less lecky is being used as gas power stations not needed. (needs less other electricity use too but ...)

    I would say much lower fire/electrocution risk on LED bulbs
    a)higher wiring amps/heating in wires - wiring last longer
    b) higher surface temperatures around conventional and CFL bulbs
    c) 12V shocks a lot nicer than a mains bolt
   
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