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Get rid of those power-hu From this . . Fit these 10W & 13W LED Got lots of 12V halogen down-lights? Is your electricity bill killing you? Maybe you should think about replacing those power hungry down-lights with efficient LED down-lights. By LEO SIMPSON W e know that home decorators love ’em but 12V halogen down-lights are a scourge. Because they are low voltage, consumers think that they are “low power”. Big mistake. Typical 12V halogens are rated at 50W but that is just for the lamp. Add in the power used by the step-down transformer, and you can easily be talking about 60 to 65 watts per lamp. And how many of those do you have in a typical room? Eight? Ten? Even more? That means that when you have the lights on those rooms you can easily be pulling 500 to 650 watts. Run those lamps for five or six hours a day and you can easily be paying more $300 a year, just for the lamps in one room. We know of one home-owner living on Sydney’s northern beaches (where the year-round climate is very pleasant) who complains about her quarterly electricity bill being over $1300 and she has to pay for gas for cooking and hot water as well! 12  Silicon Chip The energy costs are so high that she is thinking seriously of down-sizing. But guess what? Almost every room in this large 3-level house is lit by 12V 50W halogen down-lights. In total, there are some 50+ halogens – if they were all on simultaneously, the total lamp load would be over 3 kilowatts. Worse still, in summer that lamp load adds to the amount of cooling required from the air-conditioner. Working out how much extra load is placed on the airconditioner is not straightforward. You need to allow for the aircon efficiency in cooling mode but if you have 2kW of lamps on, and the aircon is on as well, you are probably talking about a 3kW load; at least. Run that for five or six hours a day and it is likely to cost about $2000 per annum, at Sydney’s present electricity tariffs. Thankfully, this home-owner does not have a “smart meter” otherwise she would be really being punished. Once you add in the cost of running items like a swimming pool pump, the air-conditioner itself and other appliances, siliconchip.com.au ungry halogen down-lights . . to this! D down-lights instead! it is easy to see how a large household could have a power bill of $1300 a quarter or over $5000 per annum. So as far as we are concerned, those 12V halogens have got to go. We have a slightly different problem in the SILICON CHIP offices. While the offices themselves are lit by efficient fluorescent troffers (see “Slash your factory/office lighting bills”, SILICON CHIP, May 2010), we have an entry corridor which is lit by four 12V 50W halogens. In fact, while I say “lit”, it is actually rather dim and gloomy (there are no windows) and while I am tempted to keep these lights off during the day because they are so power-hungry, turning them off means that we have a dark and forbidding tunnel. Well, it is not quite that bad but it is not all that attractive for an office entry. Not only that, but since these lights are on for around ten or more hours a day, and considering that our present tariff is $0.341/kWh + GST, the annual cost for those lights alone is relatively expensive at around $240 per annum and that is without allowing for the additional air-conditioner loading during the summer. So while our problem is minor compared to our frazzled northern beaches home-owner referred to above, it is still one that I would like to fix. Sure, we know that you can save some power by substitutsiliconchip.com.au ing 35W halogens for 50W units or better still, using LED replacements but the 35W approach is merely nibbling at the problem and the MR16 LED halogen replacements are still relatively expensive. And even then, you would still be running those inefficient 12V step-down transformers. Recently though, a press release crossed my desk and I pounced on it. It was for 10W and 13W down-lights, from Tenrod. These are intended as direct replacements for incandescent and CFL down-lights which are somewhat larger The two multi-LED down-lights we obtained from Tenrod LED Lighting: the 10W model on the left, 13W on the right. February 2013  13 First step was to disconnect the existing halogen downlight – invariably, these days, they simply plug in. While you are up there, make sure there are no power cables etc in the way. We elected to remove the ceiling tile to cut the hole, mainly because there was an existing downlight hole. But you could easily cut it “in situ” – in fact, installers would normally do this. than 12V halogen down-lights but why not use them anyway? We duly arranged for some sample units for this report. Two units are available, rated at 13W or 10W and they are available in warm white or daylight white. You can see their specs in the accompanying table. My immediate reaction on receiving the sample down-lights was that they are much more attractive than typical down-lights fitted with CFLs (compact fluorescents) and would would probably give a more even light distribution. And so it has proved to be. Our first step in doing this report was to take some photos of the corridor when the halogen down-lights were on. As you can see, the corridor is really quite dim, pools of light puncturing the gloom. Why home decorators regard these lights as attractive is beyond me! Our second step was to pull down one of the panels with its halogen lamp and transformer and measure the Altronics Hole Cutter: “a magic bit of kit” This is the hole cutter which has the Editor so enthusiastic. It’s the “Model Power X-625 Multi Functional Hole Cutter” and it’s available from Altronic Distributors (www.altronics.com.au) for $175.00 (Cat T2314) and includes the large carry case. It can be set to cut holes from 40-270mm diameter in plasterboard, plywood, acrylic sheet, etc. No, it’s not cheap, but if you’re involved in installing any type of audio, lighting, fans – anything needing a hole in the ceiling, this is the one you want! 14  Silicon Chip A couple of seconds later and the hole is cut. We clamped a sheet of particle board underneath the panel to give us some guide as to where to cut the hole – again, we wanted it in the same place as the existing halogen lamp hole. If this were being done “in situ”, ie, cutting the hole upwards, all the dust and bits would have been safely caught in the large clear plastic cowl, without any mess on the floor below. We wouldn’t mind betting that commercial installers, by now, are salivating at the thought! power consumption. It was around 62 watts. Just for the exercise, we substituted a 35W halogen and the total power consumption dropped to 45 watts. And for the sake of completeness, we substituted a LED replacement and the power dropped further to around 11W, with 5W of that being for the transformer alone. In each case though, there was a commensurate drop in brightness. So then we hooked up a 13W down-light from Tenrod and the power consumption measured 13 watts (funny that!), and that includes the electronic driver unit. The 10W downlight measured 10 watts, too. Then I decided to have a look at the light distribution of one of the 13W down-lights when temporarily positioned just below ceiling level in the corridor. The overall impression was that it gives a much wider pool of light and if you refer to the table, this is to be expected since the beam angle is 90°; much wider than the typical halogen lamp beam width of 60°. Based on that test, I decided that we could probably get away with three 13W down-lights for the corridor instead of four 50W halogens. That would mean a power saving of (4 x 62) – (3 x 13) = 209W. Wow, that is a saving of 84%! That would mean a saving on the annual power bill of around $200 (again, not allowing for changes to the airconditioning load). There is yet another very good reason for replacing halogen down-lights with LED models and it’s not that the halogens don’t last all that long. Because of the current drawn (12V/50W = ~4A), all wires and contacts (eg, between globe and holder, and between fitting and transformer) tend to oxidise quite quickly, leading to increased resistance. This means increased heat (with attendant fire risk – and firies will tell you of innumerable examples of that) and also of less-than-reliable operation. One user we know had several particularly troublesome halogen down-lights where bulbs failed regularly and often flickered and dimmed. They were fitted in a difficult-to-getto kitchen fitting which cannot easily get rid of heat. He’s has had to replace the lamp holders and lamp leads siliconchip.com.au It’s then simply a matter of holding the two spring clamps out of the way and placing the new lamp housing in the new hole. This whole process takes but seconds, especially using the Altronics hole cutter. Here’s the view from the opposite side. This also shows the scorch marks on the Gyprock from the old transformer: if it can do this, imagine how much heat you’re throwing away when ever the halogen downlight is on! Bring on the LEDs! several times and when removed, the wires and lamp holder were always oxidised and brittle. LED replacements would mean less current, less heat, less replacement, less aggro . . . 12mm chipboard to the ceiling panel and marking the new centre-point on that. If you are doing the same retro-fit on an existing plaster board ceiling and you want to use the X-265, you might be able to get around the problem by offsetting the new cut-out with respect to the smaller original cut-outs. But in any case, as we subsequently confirmed, the wide beam of these 10W and 13W units from Tenrod means that you too may be able to get away with less down-lights than you currently have. Doing it In our case, we were dealing with a suspended ceiling which has Gyprock panels measuring 1200 x 600mm. Rather than cutting the required holes in situ, we decided to pull each panel down and do the job in our warehouse. Furthermore, rather than messing about with a jigsaw to cut the 155mm holes, we obtained a rather fancy hole-saw from Altronics (Cat T-2314) . Called a “Model Power X-265 multi-functional hole cutter”, this is a magic bit of kit and would be a boon to anyone installing down-lights, flush loudspeakers, ceiling fans or anything with a circular mounting hole. It has a central drill and a cutting bar with two adjustable blades and it will do holes from 40 to 270mm in diameter in material thickness from 5 to 50mm thick. You just mark and punch the centre-point of the required holes, position the central drill on the punched depression and whammo, the hole is done in less than a second. But the beauty of the X265 is that it has a large transparent cowl which traps all the dust and chips so that the mess is contained. More importantly, when drilling “upward” you don’t get an eye-full of debris which can put a dampener on the whole job. This tool is not cheap but it is a great advance on ordinary hole saws (which in the size required – 165mm – are also not cheap!). However there is a problem when you want to cut a larger diameter hole centred on an existing hole for a halogen down-light. We solved that problem by clamping a sheet of TENROD LED DOWN-LIGHTS: brief specifications Model 10W 13W Voltage: 100-240V AC 1000-240V AC Beam angle: 90° 90° Working temperature: -20~40°C -20~40°C LED luminous efficacy: >100lm/W >100lm/W System efficacy: >45lm/W >50lm/W Lifetime: 35,000 hours 35,000 hours No of LEDs: 104 168 Size: 130mm x 102mm 183mm x 100mm Hole size for installation: 114mm 160mm Colours available: Daylight White or Warm White Light output: steady state light – no strobing, no flickering siliconchip.com.au Mini mains terminals If we have one criticism of the Tenrod fittings, it is the uber-tiny size of the terminals you need to connect the mains wiring to. We elected to use the two-wire mains leads fitted to the existing halogen down-lights (why buy new ones – we weren’t going to use the halogen down-lights again?). The Clipsal transformers on the old units had nice large terminal blocks but the Tenrod units have these tiny little blocks with spring-loaded connectors, which make it quite difficult to fit mains wires into – certainly not without tinning them with solder to keep them stiff enough to insert. This is not just a criticism of the Tenrod units – we’ve found in recent time most stuff coming out of Asia has similar connectors – and we get just as frustrated with them! Anyway, the photos tell the story of our installation. Instead of being dingy, the corridor is now brightly lit and welcoming. It is a great result. Final comments If you have dimmable 12V halogen down-lights be aware that these LED down-lights are not dimmable. That is usually not an issue in office, retail or commercial installations but it might be important for domestic installations. We should also comment that these LED down-lights make a great conversions from existing CFL and incandescent down-lights. They are more attractive to look at, give much better light, draw much less power and will last a very long time since rated life is 35,000 hours. At 10 hours a day, five days a week and 50 weeks a year, they should last at least 14 years! SC For further information, contact Tenrod LED Lighting, 1/24 Vore St, Silverwater NSW 2128. Tel (02) 9748 0644; Web: www.tenrod.com.au February 2013  15