Jeremy Harris

The 12V 5630 white LED strip I have uses over 2.5 A per metre, but the lower powered RGB strips usually drawa fair bit less than this. The specs vary depending on the LED used and the spacing. Most strips use 60 LEDs per metre, in groups of three. The 5050 LEDs are the most common size used in RGB strips, as they are a package that contains three (sometimes four) 3528 chips. Having three different colour chips in a single package makes the light spread more even. These strips will usually have 60 chips per metre. Depending on what you want the strips for, I suspect that 5050s will be OK for decorative RGB strips, and they will generally draw around 0.8 to 1.2 A per metre with all the LEDs on, less when only a single colour is on.

Sometimes we do seem to tie ourselves in knots when it comes to certification, in so many areas. Building standards is an area where a great deal of certification is being shown to be deeply flawed - look at Grenfell Tower and the can of worms that is uncovering about allowable certification procedures as a recent example. One major problem seems to be that we have diluted the focus from certifying equipment, materials and procedures into certifying people, and we have created a significant problem in doing so, not just because someone holding a certificate may not actually be competent (and we've all seen examples of that on this forum), but because we have taken common sense out of the equation. Something that is ludicrous may well be perfectly allowable under the rules, because it complies with the letter of a particular bit of certification. We do also have a major problem with the way we educate and train people, with the focus being on gaining a certificate of some sort, rather than on being competent to do what they have been trained to do. I fear that the whole certification "industry" that has grown up in recent years is being increasingly threatened with being brought into disrepute, because of so many examples of poor workmanship, plus the gradual drifting apart between what is allowable in different parts of the UK. Take the example of treatment plant discharge and the difference between the rules that the EA apply in England and Wales and the rules that SEPA apply in Scotland. Both have a common objective; to minimise the risk of environmental pollution, but both apply completely different sets of rules. All this does is make both organisations seem a bit incompetent, if they cannot even agree on something as straightforward as this.

As Nick says, usually four cores, unless the strip has integral controllers (some do). Worth looking at the current required carefully, as long lengths of strip may need connections both ends. The super bright LEDs can draw a fair bit of current, often enough for the LEDs at the end of a long (say 4 to 5m length) to look slightly dimmer, due to the voltage drop down the thin tracks on the flexible PCB they are fitted to. I found that connecting to both ends of a long length of white 5630 LED strip evened out the light from both ends, and reduced the size of the connecting cable needed - in effect you're creating a ring circuit, that shares the current a bit better than just connecting the strip as a radial.

Thanks, when digging around for info I had already seen his experiments. Being someone who rarely throws anything away, when an old vacuum cleaner self-destructed a few years ago (the casing broke beyond repair) I stripped out the motor and centrifugal fan unit (it's an integral unit). By pure chance, the cyclone unit I've bought has a 50mm bore stub pipe at the top, and the suction connection in the centre of the old vacuum cleaner unit is a tight fit on to a bit of 50mm OD waste pipe that is a tight push fit into the top of the cyclone unit. There were no mounts on the vacuum cleaner unit, as it was just held in place inside the moulding that broke, but luckily the centrifugal fan casing seems to be made of some sort of glass filled thermosetting plastic, which when roughed up bonds very well with epoxy. So, I've cut a hole in a bit of MDF and glued the fan unit, with a short stub of 50mm waste pipe to it. This will then be a tight push fit into the suction connection on the cyclone unit, which looks like this: The lower end of this will be screwed to a bit of ply that acts as reinforcement to a plastic bucket lid. The suction pipe (on the right in the above photo) will connect to a length of 50mm bore suction hose fed that will connect to glued in bit of 50mm waste pipe at the side of the saw box. The Erbauer saw has an extract connection that's a bit smaller, around 30mm diameter, so there will be another length of flexible hose from there, via an adapter, to another glued in length of 50mm waste poking out the side of the box. The idea is that I'll make up a push-fit U shaped connector to allow the extract to be connected to the table saw, and another flexible hose with appropriate adapters that can push fit on to connect to the mitre saw extract connection, plus a long length of 50mm flexible hose to use as a workshop vacuum. By having standard plumbing 50mm push-fit waste connectors it should be easy to connect the unit up to anything else, and I think it's just as easy to plug and unplug push-fit pipes than faff around making proper blast gates to do the switching. I'm looking to make it a bit lower in height than my bench, and fitting lockable casters to the base of the box, so that I can wheel it under the bench when it's not in use as a saw. With luck that will give me an incentive to keep the bench clean, by having a vacuum right under it all the time! Another bit of kit that the box will have is a flat cone "floor sucker", that again can be connected to the vacuum cyclone. The idea is that this will work as a fixed extract when sweeping up the workshop floor - I should be able to just sweep stuff towards the slot down near the floor and have it get sucked up. As soon as the epoxy has cured I'll take a photo of the vacuum motor unit fitted to the cyclone top.

In practical terms, people vary a great deal in what they find comfortable, or intolerable. I hate traffic noise, for example, others happily live next to main roads and never notice the constant noise. Any standard that seeks to apply very rigid and very expensive to demonstrate absolute compliance voluntary standards, seems to be as if it would be better placed as to have them as an objective to aim for, rather than a rigid set of restrictive rules. Personally, I think that all the many super-duper house performance standards should be just scrapped, and our building regulations made fit for purpose. If Part L1a was improved to require near-PH levels of insulation and airtightness, and Part F was changed to mandate heat recovery ventilation, then we would be 99% of the way towards having houses with as low a practical energy use, and high comfort levels, as we can get, bearing in mind that the biggest variable by far is the way people choose to live in a house. PH certification is completely pointless if someone buys the house and then insists on leaving all the windows open for fresh air, for example, or insists of hanging up soaking wet washing indoors, so increasing the internal humidity and making the house less comfortable. By the same token, we don't have the luxury of being able to build new houses only in quiet areas, to the noise level from ventilation system really is a very minor consideration, if heavy traffic rolling past outside 24/7 drowns out any ventilation system noise. We've had over 30 years for the world to adopt PH as a standard, and it has failed, dismally. Only a very, very tiny proportion of new houses built over the years since it came about have been built to that standard. The same goes for the valiant efforts of the AECB, with their Gold, Silver etc standards, except they've had far less success in getting anyone to take notice of them. Ireland is going in the right direction. They are mandating better building standards in their regulations, but far more importantly, they are trying very much harder to enforce those regulations. It took a housing disaster, during the boom years of the "Celtic Tiger" to ram the need for this home, with "ghost estates" of sub-standard new homes that will probably end up having to be demolished, but nevertheless the Rialtas na hÉireann have had the testicular fortitude to tighten both regulations and their enforcement whilst coming out of a deep recession. New homes in the UK are dire by comparison with the performance of those now being built in the RoI, especially in those areas where PH-type standards are being applied in the form of local building regulations.

My plan is to make the table bigger than the timber box it sits on, with that timber box housing the home made dust extractor (which I'll use as a general purpose workshop vacuum as well). I've decided to add hinges to the table, so that I can lift it to adjust the saw depth and angle easily, and have some storage space in the box for spare blades, the fence when it's not being used etc. The fence will be a length of 2" x 3" x 1/4" aluminium angle I happen to have, faced with a bit of 12mm thick acetal sheet that I also happen to have. To support both the fence and be able to bolt down the mitre saw, when the circular saw isn't being used, I'm going to rout out two parallel grooves in the table, perpendicular to the blade, either side of it and 360mm apart. Into these grooves I'll screw some T slot extrusion, so I can secure either the fence or the mitre saw (which has fixing holes 360mm apart) to the rails, using T nuts and hand wheel screws. I'll add a T bar to the end of the fence that runs along the front edge ot the table, so that it stays square. I reckon that having the fence tightened down right behind the blade should help keep it rigid. Photos will follow once I have it all together. I tested the old vacuum cleaner with the dust cyclone just now, and it's extremely impressive, more impressive than our old Dyson DC-01, which was forever clogging up and was an evil thing to clean out properly. I think the secret seems to be that these Chinese cyclone units are longer than the Dyson efforts, and have a properly shaped intake, the promotes a higher velocity swirl. I'm very impressed for what was a pretty cheap bit of kit.

Dead easy. It is well-instrumented and demonstrably uses less primary energy than the PH criterion. QED I agree that some consultants make a living out of making it all seem impossibly difficult, and so complicated that only someone who charges a small fortune for their services can possibly ensure that a house meets the PH standard, but not only is that BS, it's also contrary to the general principles that were expounded by Bo Adamson and Wolfgang Feist when they came up with the idea.

Sounds familiar. Their support ticket system is dire, as they just ignore every message you send them, it seems. I did get reasonable support via the phone, and asked if they could review their dysfunctional support ticket system. It remains to be seen if they do anything.

This is a timely reminder, as I'm going through similar shenanigans with British Gas, having switched to Iresa a few weeks ago. Currently BG owe us around £130, and are insisting that our direct debit will be taken each month, at a revised figure that seems to have been plucked from thin air. Needless to say the DD has been cancelled, and I now anticipate a long and drawn out struggle to get BG to pay us what they owe. It remains to be seen if Iresa customer service is any better - I've not been impressed so far.

That I like, as it does away with the need for the riving knife, which although of some use, apart from providing an attachment for a guard, would need to be fixed to the pivot somehow, to allow cuts to be made at an angle. Although I agree with @TerryE, it doesn't makes much sense from a financial viewpoint, I hate waste, and I have this pretty much unused, 2 kW, 235mm circular saw just sat doing nothing. I'm also part way through building a cyclone dust extractor box for the new workshop, so the current plan is to make a box with a flat top that will do three things. It will be the dust collector for the workshop (using an old 1800W vacuum cleaner motor that I've been saving for a useful job, with one of these cyclone separators: http://www.ebay.co.uk/itm/Plastic-Cyclone-Powder-Dust-Separation-Collector-Filter-For-Vacuums-Cleaners-/272836140016?hash=item3f864d1bf0:g:DSgAAOSw32lYx4uM and an old plastic bucket with a lid), it will be a small saw table, with two bits of alloy T track set into the top to act as guides for the rip fence, and also as a mount for my mitre saw, which will just bolt down to the same T tracks that are used for the rip fence (with the table saw blade retracted below the table surface).

Some may remember that when I burned out my faithful and very old Black and Decker circular saw (which must have been over 20 years old), when finishing off our bamboo flooring, I made a stupid purchasing decision and went down to Screwfix and bought a large Erbauer as a replacement. My reason for buying the Erbauer (apart from the price) was that it took the same big blades as my mitre saw, and as I had a fair few mitre saw blades I thought there was some logic in having the same size. The Erbauer in question is this one: http://www.screwfix.com/p/erbauer-erb596cws-2000w-235mm-circular-saw-240v/71604 The problem is that it's far to big and heavy to use most of the time, so I went and bought a Makita cordless saw, which is a great bit of kit. As a consequence, the big Erbauer has just sat in it's box for a couple of years, doing nothing except being moved about from one storage location to another. One really nice feature about this saw is that the base plate is a bit of 3mm alloy plate, screwed to all the rest of the stuff. This means that it will be dead easy to just make a new plate that could be set into a saw table, retaining all the angle and depth settings of the original (albeit with the need to bend under the table to get at the handles to move things). Having looked around the web, there are lots of ideas around for making table saws, BUT, there is also what looks to be a safety "war" between US and UK builders of these things. Most UK sites condemn the US practice of having no riving knife with attached safety guard; most US sites tend to suggest the safety guard and riving knife is a pain and limits flexibility and ease of use. I can't see an easy way to fit either a riving knife or safety guard when I fit this thing under a table. I can't use the existing guard, as that would mean leaving a very wide blade slot, and that's more dangerous than not having a guard, as stuff can get thrown up around the blade or jam it. So, I'm proposing to go down the US route, and have just the blade coming out of a narrow slot. I can't see that it's any more dangerous than running a slit saw or flycutter in a milling machine, TBH, and think it just needs to be treated with respect. I will fit a no-volt switch and big E stop button. So, what's the collective view on how mad an idea this is, and has anyone here done something similar?

I can understand that bit, the systems can be a bit challenging, but around 90% of getting a house to PH levels of performance is basic stuff, insulation and airtightness primarily. As for understanding stuff, I'm constantly amazed by the technical knowledge that people like bricklayers have. In their heads they are constantly solving geometric problems in 3D, and using hard-won skills and experience to keep walls true and plumb, whilst thinking ahead several courses to make sure what they are doing now is going to make what they need to do later easier. I'd argue that that skill is every bit as technically demanding, perhaps more so, than the knowledge needed to work out the heat losses from a house, for example.

That is absolutely spot on. People go into science because they are curious and interested in stuff, and, perhaps more importantly, they aren't too focussed on earning loads of money (a look at the adverts for scientists in the back of your weekly "comic" soon shows what the pay is like!). Teaching science is challenging, but no more so than teaching maths, I think. I remember hating maths, and not being able to understand what on earth integration (and differentiation) was about, until I was fiddling around with a project at home and needed to find the area under a curve. All of a sudden the concept of integration became clear. One bad side effect was that I went back to school and spoke to the maths master about it, saying how I'd suddenly grasped what calculus was about by looking at something practical. Sadly, he was from a pure maths background and dismissed my suggestion of having some practical examples to illustrate maths and put me at the back of the class for having the temerity to suggest something..........

@jack, Point taken, but I never rose to the dizzy heights of the Chief Scientist (in reality CSA, the Chief Scientific Advisor), I was just a senior principal scientist before being kicked into management. Arguably, the main issue is the divide between architecture and engineering. I doubt that your build would have had those thermal bridges where the steels go through if the design, from an architectural standpoint, had considered the engineering challenges involved. In the recent past (as in over the past 50 to 100 years) we have allowed architecture and engineering design to diverge, at least for dwelling design, and they have become almost entirely separate disciplines. The classic case is where the architect designs something, with little or no thought as to how the desired thermal performance is going to be achieved, and then metaphorically chucks it over a wall for an engineer to sort out how to actually build it and make it perform. In our case, I knew nothing about architecture, so started from the desired performance, and then made compromises in order to get the house to look a bit nicer. This is, I believe, the complete opposite of the process that most houses go through at the design stage. The main benefit was that I started with a baseline performance (basically just a sealed, well-insulated box), and then worked back from that to get something that looked reasonable and could be built without compromising the performance too much. My target was to meet or exceed the PH performance criteria, right from the start, only because it seemed to be the only proven methodology around. If we were to adopt a similar process for all new builds, by merging the architectural design, technical design and cost engineering, with the emphasis on the latter two, then we'd undoubtedly have better performing new houses. If self-builders adopted this approach then I'd argue that it would be pretty easy to achieve PH performance, at little or no additional cost.

The problem is that every man and his dog will change the scaffold the moment your back is turned. Everyone on our site, with no exceptions, changed the scaffold around at least once, sometimes a few times. There's no way a scaffold company can constantly monitor what contractors do after they've erected a properly certified scaffold. I did notice that our scaffolding guys always took a few photos with their phone after they had left from either the main erection or the couple of times I called them back to change the position of lifts. I would guess that was them covering their backside in the event of the scaffold being altered.

That could be down to their web site update policy. IIRC, our external-facing web site at work only got updated about once a month, with the exception of automatically linked (and pre-vetted) news releases. One company, that I'm still in vehement disagreement with over their breach of copyright and false information about our build, and who I would heartily recommend that everyone avoid like the plague, told me that they struggled to get their web site updated more than a few times a year. Certainly they have not removed the copyright breach material, nor corrected the false information, in well over a year now, hence the reason for me having to spend time and money taking legal action.

My guess is that the sum of money is just too small to warrant any form of further action, and I'd also guess that Durisol have learned a great deal from the incident, and will modify their advice accordingly. I suspect Durisol will look at it as a useful learning exercise, of net benefit to them in the longer term.

Yes it is, it's a doddle. I've run our as-built house configuration through PHPP, and despite being an all-electric house it still comes in within the PHI standard. I used an off-the-shelf passive house foundation and frame supplier, and that dealt with all the building-related technical and quality issues, so my main input was in design and modelling, plus systems specification. It wasn't in any way technically difficult or demanding work. The hardest part for me was the artistic element of the architectural design - the technical stuff is easy, the art and design doesn't come naturally to me. FWIW, our chosen frame and foundation system supplier offered a thermal-bridge free construction method and guaranteed PH airtightness level as a part of the package. We came in at around 2/3rds of the max allowable PH permeability at the very first air test, no remedial work or additional air testing was needed.

That's good news, Ian. Around £1,000 for a bit of research and letter writing seems a good return on your investment to me!

Sitting on my desk right now (but not spinning) is a Crookes Radiometer. It spins around quite merrily when the sun is shining on it, and has done for the past 30 years or so. For a year or so I pondered on what drove the thing, as, being in a vacuum (or so I thought) it appeared to defy the theories of relativity. The answer is that it's in an imperfect vacuum, and so there are a few air molecules inside the sphere, enough to be moved and provide motive force to what is a pretty simple heat engine. It is true that photons have zero rest mass, but not that they may always have zero mass. Things get messily complicated when you get to the behaviour of wave/particle systems at, or possibly in excess of, the speed of light. Getting your head around a zero rest massless entity (that is never at rest) and that possesses energy and momentum as intrinsic characteristics, is something that took my small brain some time to grasp, and is well off-topic for this forum.

The simple and straightforward answer is that it is not at all difficult, challenging or expensive to build a house that meets or exceed the now pretty old Passivhaus standard, and there is little merit (other than bragging rights) in going through the very expensive certification process, in my view. As an example, I knew sod all about building, architecture, energy efficient construction etc, before embarking on our self build. I did some home work, learned a fair bit in the process, used no consultants or experts, and ended up with a house that exceeds the Passivhaus energy performance standard. It wasn't hard to do, didn't cost the earth, and frankly there was nothing technically difficult about it at all. The major issues were making sure that everyone working on the house paid attention to the detailing, nd overcoming a load of prejudices and plain old disbelief. There's nothing magical or mystical about building a low energy house, that's comfortable to live in, although there seem to be a host of "experts" intent on convincing the unwary that the only way to achieve this objective is to pay others lots of money...................

Welcome Ivon. I strongly suspect that the problems are as you say, poor installation and clueless setting up by Kingspan. The default settings on these units are hopeless for the UK climate, but the units themselves are very good indeed, when properly installed and set up. I have an identical unit, badged Glowworm, and it took a fair bit of work to get it set up properly. Both Kingspan and Glowworm had near-zero technical understanding of the Carrier ASHPs they were buying in, and consequently both pulled out of the market after a number of problems they incurred. The major failing is that, by default, these units are set with a barking mad weather compensation curve, and a hot water capability that simply doesn't work well in the UK climate. The default settings mean that the ASHP will go into defrost mode two or three times an hour, with the compressor and 4 way valve working overtime to try and keep the thing running. If set up correctly, and if set to not produce very hot water, they are fine, very quiet, efficient and reliable. If set to try and deliver hot water at 55 deg C (the default DHW setting) the efficiency will be dire, and the unit will run flat out for long periods to try and get that hot. In general, most single stage monoblock ASHPs like this don't work very well when trying to deliver hot water, they work far better when only delivering lower flow tempratures.

You can programme the slope of the flow temperature versus ambient temperature with a bit of faffing about via the command unit, but I've found that just setting it for a flat 40 deg C seems to work OK. The relays I used were 12V ones, that plug in to DIN rail mount sockets, and have additional LED modules to show which relay is on. The DIN rail socket fits into a small consumer unit type box (I bought a cheap one with a clear cover so I could see the LEDs). I powered the relays via a 12V Meanwell DIN rail mount power supply. The relays I used were standard 12V DIN rail mount sockets type ones, with the LED indicator modules, like these: http://www.ebay.co.uk/itm/RELAY-MODULE-2CO-12VDC-/172741730264?hash=item2838359fd8:g:r4cAAOSwgv5ZSlRh The diodes were cheap 1N4001's soldered together with leads to wire up to the relay modules. To allow easy connection of the external thermostat wiring I used DIN rail terminal blocks, like these: http://www.ebay.co.uk/itm/2-5MM-12-PIECE-DIN-TERM-PACK-/172750888899?hash=item2838c15fc3:g:s5IAAOSw8GtZUmeF these fitted behind areas of the consumer unit box where I hadn't punched out the front covers, to hide the terminals. The Meanwell 12V power supply I used was one of these:http://www.ebay.co.uk/itm/Mean-Well-DR-15-12-12V-15W-Step-Shape-Din-Rail-PSU-/132076460496?hash=item1ec05ed9d0:g:anMAAOSwnHZYifqK (it needs to be the step shaped one to fit a consumer unit type housing, I think, and keep the terminals protected) IIRC, I used a 9 module DIN housing, just a bare consumer unit type unit with no switches etc fitted, like this one: http://www.ebay.co.uk/itm/Consumer-Unit-enclosure-MCB-Fuses-box-coffret-electrique-5-9-13-18-26-module-way-/251353151094?var=&hash=item0 I can check tomorrow to be sure whether it's a 9 or 13 module box.

The temperature drop across the PHE depends on the relative flow rates and the plate area, but I worked out that the 44kW rated one I used was OK for well over 10 kW at the lower temperature that we're running at, and our ASHP is only rated at 7 kW. The 44kW rating seems to be for a higher temperature differential and higher operating temperature, typically the sort of internal temperatures that combi boilers operate at (so maybe 70 deg C on the sealed primary, 55 deg C of the DHW secondary. In your case, given the modest price difference, I would go for the 66 kW version: http://www.wiltec.de/house-garden-pump-plate-heat-exchanger/plate-heat-exchangers-stainless-steel-cupper-brazed/hrale-stainless-steel-heat-excahnger-30-plates-plate-heat-exchanger-max-66-kw.html. In practice I've found that the temperature drop across the PHE rarely exceeds 2 deg C, so I'm sure my derating is a bit pessimistic. Given that the 66 kW PHE is less than €10 more than the 44 kW one: http://www.wiltec.de/house-garden-pump-plate-heat-exchanger/plate-heat-exchangers-stainless-steel-cupper-brazed/hrale-stainless-steel-heat-exchanger-20-plates-plate-heat-exchanger-max-44-kw.html , there doesn't seem much point in going for one that might just about be OK. I found that the maximum flow temperature for our location and installation seems to be around 40 deg C. Any higher then this and the unit starts to defrost in cool (around 3 to 4 deg C) weather when it happens to be fairly damp. The worst case for frosting seems to be still, cool, misty days, the sort of weather where your car will have condensation over it in the morning. Cold dry weather is fine, the risk of defrosting almost goes away as soon as the air temperature drops below freezing point. As an extra bit of info, the 44 kW PHE we have had a pressure drop when running a shower at 10 litres/minute of slightly under 0.03 bar, which is so low as to be negligible (our incoming supply is at 3.5 bar, so this is less than 1% pressure drop). The 66 kW PHE has a lower pressure drop; for a shower at 10 litres/minute the drop would be just under 0.02 bar. We connected the smaller connections to the mains pressure DHW feed and the larger tappings to the circulating pump and buffer tank.

My experience (which may not be typical) is that market value is, at least at the moment, negatively impacted by over-emphasising the low energy usage of a house. When we had our house valued a couple of years ago, the valuer knocked 5% of the value because, in his words, it was an eco house and that made it of limited marketability. Given this, and the relatively high cost of Passivhaus certification (at least £2k, probably more when you add in the premium that every supplier is going to chuck on for providing the additional information) then I don't think it makes sense, unless you really want to proudly display the plastic plaque you get from the PHI. Far better, in my view, to design the house to meet the same sort of performance level, and then keep the energy bills. That way, when you come to sell (if you ever do) you can just make copies of the bills to show any prospective buyer the running cost. I'm inclined to think that the low energy classification systems, be they AECB, SAP or Passivhaus, just aren't on the radar for most buyers, and some may well be put off by what they see as odd or complex features, like well-sealed windows, MVHR, minimal heating system provision etc. Far better, I think, to just have a note on the sales particulars that says "this house costs £XX to run every year, and the vendor can provide bills as evidence".