Jeremy Harris

The convention is gross internal floor area, of all habitable floors. The footprint will usually be larger than the ground floor area, by the thickness of the external walls. For example, our 130m², 1 1/2 storey house has a footprint of about 85m². a ground floor area of about 75m² and a first floor area of about 55m². If our house was a bungalow on the same footprint then the floor area would be 75m². Although a bungalow would have a lot smaller habitable area, the foundations and roof cost would be the same as for the house, the only saving would be a small reduction in the external wall cost and the cost of the internal stud walls and flooring on the first floor. Not much of a saving, really.

Been trying to pin down prices for the electric radiators, and it seems that the above guess may be an underestimate. It looks like a 1.9 kW unit is around £1,400, or was a few years ago. The same capacity night storage heater, with modern controls (as required to meet building regs now, I believe) would cost about £600. The night storage heater would run on E7, or an equivalent cheap rate off-peak tariff, the Fischer radiator would run on peak rate electricity, so for the same heat output the Fischer would cost around 50% to 60% more to run. A bit of a double whammy really, with the capital cost well over double that of a decent storage heater and a running cost at least 50% higher. .

Just had a quick look on eBay and there are a few Fischer radiators for sale. Asking price seems to be around £500 to £800 for second hand ones. At a guess I'd suggest that new they must be over £1000 each. That's pretty expensive for an electric heater.

I suspect you're spot on, as the quote from Sunamp makes it clear that shifting a large number of units seems to have been their priority. I can't help feeling they will live to regret this, though, if they end up with a reputation as bad as that of Fischer/Premier.

I can't believe that Sunamp weren't aware of Fischer's long history of misleading advertising. They've been pretty well known for this for years, and continue to play the same game year after year, seemingly without anyone doing anything to stop them. 2014: 9 issues raised with the Advertising Standards Agency, 8 upheld 2015: 5 issues raised with the Advertising Standards Agency, 5 upheld 2016: 3 issues raised with the Advertising Standards Agency, 2 upheld 2018: 3 issues raised with the Advertising Standards Agency, 3 upheld Reading through the ASA complaints, they are all much of a muchness, relating to misleading claims/content.

I can't believe that Sunamp weren't aware of the way this company behaves; I thought it was common knowledge, as they've been using the same sales model for years now. The basic premise is to sell stuff that's "reassuringly expensive" to people who believe that paying more gets a better product. In the case of the Sunamp, to some extent that's true, but we don't know how much of a markup is being applied, as, just like double glazing companies, they never publish prices and tell every customer they are getting a "special deal". The customer comments on that link above should be compulsory reading:

Fischer's niche marketing is to target those who fall for their pitch about comfort, the environment etc, and who don't question things too closely. They advertise in publications aimed at senior citizens in the main (hence the reason I got targeted!). They never give away the price of anything, but insist that potential customers must have a "free survey". Inevitably this "free survey" is really double glazing type sales stuff. It works, and lots of people have bought their electric heaters filled with magic clay etc.

In your case, maybe, but not for most systems, where there will just be a single thickness of pipe, most probably copper, between the toxic antifreeze and the hot water storage.

I agree, it seems to be a poor choice to market this product using a sales company that is pretty well-known for using double glazing sales tactics. The product is pretty good now, and they do seem to have ironed out the bugs in the control system as far as I've been able to tell (winter testing should prove if this is the case beyond much doubt). Apart from the inevitable price hike that will come from the markup that Fischer/Premier/Any-other-name-they-trade-as will apply, my major concern would be whether this sales company are able to provide technical support. My experience, and that of others here, has been that Sunamp have seemed to struggle a bit with technical support at times, and they know pretty much all there is to know about the way their product works. Is it likely that a high-pressure sales outfit will be able to acquire the knowledge and skills needed to be able to ensure installations are reliable and work as intended? Frankly I doubt it, unless they invest a lot of resource into training their technical and installation teams. I foresee problems akin to those that beset the heat pump sales people a few years ago, when thousands of heat pumps were sold that were a poor match for the customer requirement and consequently failed to perform as promised. We're still seeing the repercussions of that fiasco now, with people being wary of installing a heat pump, based on some of the tales of woe that have been fairly well publicised.

Just found some more stuff out. It seems that Sunamp have done a deal with Fischer: http://www.puretemp.com/pcmatters I've also discovered that Fischer seem to trade as another company based in Leicester, too: https://www.premiersmartheat.co.uk/services/aquafficient/ This doesn't surprise me, as they are pretty well known for having the "double glazing salesman" approach to sales and marketing. It's all about bamboozling people into buying stuff, by never telling them the price until they've got a foot in the door and have been given the chance to do the hard sell.

That thought had crossed my mind! I'm betting that their mark up will be somewhere around 100%, based on the way they market their storage heaters, portable heaters and conservatory heaters.

Just had some junk mail from that well-known rip-off merchant, Fischer Future Heat (the people selling very expensive electric heaters on the basis of efficiency). Interestingly, it shows an image of a product they call the "Aquafficient", which looks identical to a Sunamp, but with a different name on the front. It's advertised with the tag line "You can make a difference today and STOP using carbon fuels for a better world", which is frankly stretching credulity a bit. The best we can manage, with a 6.25 kWp PV array and a Sunamp is to reduce our reliance on grid supplied electricity for hot water to about 30% or so. Looking around the Fischer Future Heat website https://www.fischerfutureheat.com/electric-heaters/aquafficient/ there is very little detail, but searching a bit further I found this brief mention of the Aquafficient that seems to show that it is indeed a Sunamp with a different label on the front: https://heatingguy.co.uk/aquafficient/ . The photo on that website is the one on the junk mail I received. I'm not sure what to make of this. Maybe Sunamp have decided to rebrand their product, but if that's the case why on earth have they chosen to team up with a well-known bunch of shysters like Fischer? Fischer have a pretty well known reputation for advertising that sails damned close to the wind, and they tend to use the "baffle with pseudo science" marketing technique in order to deceive people into thinking that their over-priced stuff is somehow "special".

First off, 15 kW seems high, is that allowing for diversity? Normally a domestic cooker would be rated at 10 A + 30% of the full load current for the appliance from the MIs. If there is a socket outlet on the cooker switch then add another 5 A. Secondly, unless there are some specific circumstances that require a high level of mechanical protection, then you wouldn't use SWA indoors for something like this, but twin and earth. Allowance needs to be made for the installation method and insulation, but the cable size required is best obtained from the tables in BS7671, rather than the TLC calculator, as the latter tends to under-estimate the cable size required a fair bit of the time (it doesn't take proper account of derating or the installation method, AFAICS). If the cooker is rated at 15 kW at 230 VAC, then the full load current would be 65 A and the load for calculating cable size, accounting for diversity, and assuming no additional outlet at the cooker point, would be 10 A + 19.6 A = 30 A for calculation purposes. Using reference method 100 (T&E cable running across a ceiling with insulation above) gives a cable size of 6mm² (34 A max) and a voltage drop of 7.3mV/A/m which is ~3.1V for 14m (1.35%) which is within the maximum allowable. Increasing the cable size to 10mm² gives a capacity of 45 A and a voltage drop of about 0.8%. My inclination would be to use 10mm² T&E to give a bit of additional headroom, but 6mm T&E would be OK.

By the same token, the antifreeze used in any heat pump installation also has to be the more expensive stuff. The consequences of the risk of contamination from using something like car antifreeze doesn't bear thinking about, and it would be foolhardy in the extreme to use it in a domestic water heating system.

No it won't, as the problem is not one of the controls, but of getting the physical system to respond within the defined limits. Variable speed pumps have a non-linear relationship between speed, flow rate and head, hence the need for the flow sensor, and the flow sensor is adversely affected by things like dissolved gas content (this caused problems with the Sunamp PV). Add in the wide range of heat output from the ST system and the things gets to be more trouble than its worth for a domestic system. It's a heck of a lot easier to just use PV, as electricity is a lot simpler to control. It really comes down to simplicity being a very significant advantage for any domestic system that has to operate, with a minimal degree of servicing, for a couple of decades.

Sadly that option isn't at all easy to do. It could be done with some careful controls to ensure that the charging hot water circuit is always over 58°C and below boiling point, but it would need something like the control system that was used in the old Sunamp PV, with a flow sensor, temperature sensors and a variable speed pump. I've looked at doing it (during the long debate about Sunamp charging methods) but it's not exactly easy to do.

I'm not sure about Brave, I've not tried it. I'm running Firefox 67.0.1 at the moment, and have Pale Moon 28.5.2 installed just to play around with.

I've just checked and Firefox seems to be using about 1Gb of memory on a Core i7-8550U machine that has 16Gb of DDR4-2400. Seems to still be a bit of a memory hog to me. I've not tried Brave, but Pale Moon definitely seems lighter on resources than Firefox, and doesn't need fiddling with CSS tweaks to get things arranged sensibly (i.e. tabs below the bookmarks and menu bar). Despite having used Firefox for years, it is gradually beginning to annoy me more and more with each "upgrade". So far the CSS tweaks have been broken by updates twice, so now I have updates turned off by default and wait to see what stuff's been broken by them before I decide whether or not to implement them.

They take a solid core wire one side and a stranded core the other side. The solid core pushes in and locks, and the stranded core is fitted by squeezing the lever down, inserting the wire and then letting go so it grips. They are ideal for wiring lights, where you have a bit of 1mm² or 1.5mm² solid wire that needs to connect to a stranded wire that is connected to the light fitting.

One thing that might make a difference is your choice of hot water storage device. We have a Sunamp that is electrically heated, takes up a fraction of the space that a hot water cylinder or thermal store would and has much lower losses. After a bit of a glitch, when Sunamp radically changed the heating and control system when they redesigned their units, Sunamp seem to have now resolved the control problems with the electrically heated UniQ range and we're finding that it works very well.

The golden rule, never to be broken, is to turn off the power and then always check to make sure that the circuits you intend to work on are really dead. It's not that unusual to find that things are wrongly wired, or mislabelled, so you can think the power is off when in reality it isn't, hence the need to always check (with a meter, rather than one of those supposedly voltage indicating things). When measuring voltages on circuits that are disconnected it's not unusual to find that a meter shows a low voltage on the wires. This is usually just an induced voltage from adjacent cables, and is really just a artefact from using a high impedance voltage measuring device. Ideally, lock off the isolating switch whilst you're working, in case anyone comes along and turns the power back on, not realising you're working on it. I have a small lock that fits over an isolator switch to prevent this.

FWIW the ones I keep boxes of are 773s and 224s. 773s will pretty much cover most rigid wire connection requirements in everyday stuff and 224s are useful for connecting rigid wire to flex.

That's my primary concern, too. I believe that our neighbours problems may well stem from one or more of the relatively frequent power cuts we get around here, as the system relies on being powered up in order for the boiling prevention controls to work. I don't like the idea of this at all, and would want a system that's fail safe when the power goes off and the sun is shining.

A crude, but reasonably simple test is to isolate the power and just measure the resistance between the exposed metal case and the earth* conductor. All the imported LEDs I tested had an open circuit when checked. When I opened them up I found the earth wire just floating loose inside, having never been connected. *I'm going to stick to using the term "earth" for both the conductor and connection from now on, rather than CPC or PE (Circuit Protective Conductor or Protective Earth)

My pet hate too. I bought a lot of LED outdoor lights (that turned out to have a floating earth wire internally, another story) and ended up rearranging them internally so there was room for a terminal block. The daft thing is that these lights had a nice sealing gland for the cable and room inside for a bit of choc block so it would have been cheaper and easier to make them without the short (and useless) lead. If anyone buys any metal cased LED outside lights then I strongly recommend testing them to make sure the metal case is really earthed. It was only my suspicious nature that led to me discovering the lack of any earthing. On a related topic, I'm not that comfortable with the use of PVC flex on these things, either. The lights outside the garage of our old house had been wired with white PVC covered flex and it cracked quite badly, presumably as a result of sunlight degrading it. All the flexible cable on the lights here is H07RN-F, as it's rated for outdoor use.