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The not very affordable low energy house

Britain’s first low cost ‘energy positive’ house, which can generate more electricity than its occupants will use, opens on Thursday despite George Osborne axing plans to make housebuilders meet tough low carbon housing targets from next year.

The modest three-bedroom house built in just 16 weeks on an industrial estate outside Bridgend in Wales cost just £125,000 to build and, said its Cardiff University designers, will let occupants use the sun to pay the rent.

Problem 1: that price doesn’t include the land. Which is, of course, the major cost of building anything anywhere anyone actually wants to live.

According to Jones, the building costs of the 100 squar e metre energy positive house could drop below £100,000 if several were built at the same time. “We save money and space by making the photovoltaic panels the roof itself and by dispensing with radiators and making the air collector part of the wall,” he said.

Solar panels degrade over 20 years. so the entire roof has to be replaced every 20 years then?

Very cheap that, very cheap.

48 thoughts on “The not very affordable low energy house”

  1. Hmmm. Build cost doesn’t sound _too_ bad. Enviro regs are such here that build costs are closer to €3000 per square metre, and that’s for flocks of bats. Which the government is fighting back against with rent caps.

    And the roof? A flat you’re going to be resurfacing at least on that kind of timescale – albeit with cheaper materials, that albeit don’t actually generate cashback once installed. But we are agreed that these solar thingies are going to be a price-competitive energy source at some not too distant point? So it’s no surprise that there are some experimental things going on and some fanatical early adopters?

  2. I take it the house conforms to all the other lovely new building regs that the Welsh Government has decided on, including fire sprinklers in domestic houses?

  3. “by dispensing with radiators”

    Fortunately radiators are unnecessary in a climate like Southern California. Oh what? It’s in South Wales?

    The house would make even more money on an Economy 7 tariff!

  4. Also, do the power calculations take in to account the electrical appliances the average 3-bed house dwelling family use? An oven, dishwasher/washing machine (especially now models are all cold-fill), kettle and the odd pair of hair straighteners might affect payback rates considerably

  5. If you don’t need a roof, why build one?

    Tis a PR stunt, however – the costs are not particularly special.

  6. Rhyds

    The sainted intended occupants of this house would never, in a million years, have a dishwasher or, shudder, a hair straightener.

  7. “especially now models are all cold-fill”

    Why is that…?

    We get gigalitres of free hot water from our solar panels yet both the dishwasher and washing machine are cold-fill…

  8. From what I gather it’s down to manufactures (or probably EU regulators) deciding its “more efficient” to heat up a small quantity of water electrically in the machine than it is to use the tank of hot water you have sitting there heated up anyway. That’s perfect for the new fashion for 30 degree washes, but not for anyone wanting a high temperature wash. My cold fill only machine is noticeably slower at 40 degrees than at 30.

  9. Surreptitious Evil

    And we note that it is only power-positive in the summer. When we don’t need lots of houses demanding to be paid for producing minuscule amounts of energy.

  10. Cold wash is the direct result of eco-wibble tyranny. They don’t work as well as hot water.

    Altho’ a seeming minor matter they are a manifestation of the eco-evil that says humankind must now adapt to nature rather than adapt nature to ourselves.

  11. Bloke in Costa Rica

    100 m²? That’s 90% of the size of my (not very large) apartment. I daresay you could shoehorn a family in there, but it’d be a squeeze.

  12. Hmmmnnn…

    But dishwashers still require something in the order of 50°C to get the dried-up shyte off the plates…

    I had a customer here that tried to run ‘off grid’ – not for any eco-loonery but because they’d had a house built at the top of a hill overlooking Limassol without a grid connection.

    They had a vast solar panel array and a whole garage full of batteries yet it still couldn’t support their chosen 21st Century lifestyle – swimming pool, electric cooking, kids computers, satellite TV, TV games, etc.

    So I can’t imagine it working in Wales…

  13. Serious question here.

    I don’t have, and never have had, a dishwasher beyond a bowl, a sponge and elbow grease. I’ve never been convinced that they save much time given the rinsing you need to do before the dishes go in, the careful placement in the racking, and then the remedial manual clean up of the bits that the dishwasher can’t deal with etc etc?

    Are they really that useful as well as being massively power hungry compared to bowls of hot water for handwashing?

  14. “cost just £125,000 to build”

    Add in another £50,000 for the builder’s margin to get selling price.

    Unless people build houses as a hobby, and not a business.

  15. In the longer run, solar panels will be made as roof tiles, to the standard UK clay tile size, with flying leads to plug into a bus cable below.

    If implemented this way, any tiler can replace one tile at a time across the roof, and installation doesn’t need special skills, nor full scaffolding and roof cover.

    That makes this every-20-year replacement more feasible.

  16. We get gigalitres of free hot water from our solar panels yet both the dishwasher and washing machine are cold-fill…

    Do the dishwasher and washing machine have sensors that cut out if the input water temperature is higher than ‘tepid’? If not, why not just plumb them into the ‘hot’ supply and give the machine’s heating a head start?

  17. BraveFart:

    Ditto. Just me and my wife in the house, so not a huge amount of washing up to be done, and it gets done immediately after we eat so not much chance for stuff to get dried on. Perhaps they are worthwhile for larger households?

    Also, my clothes never really get properly dirty (work in an office, don’t play football/rugby, no kids) so I find a cold wash does the job most of the time.

    (Not making a judgement on those with dishwashers or those who use hot washes, just stating my own situation)

  18. BraveFart, they might – as GlenDorran says – be more use for a larger family, but otherwise, they are just a useful gadget, a ‘nice to have’. Mine brings glassware up a treat!

  19. The big benefit of dishwashers is that they’re “fill and forget”. You can leave them running to sort the dishes out while you spend quality time with your significant other/kiddies/the cat.

  20. Or you could save on storage space and the effort of putting stuff away by having two dishwashers. At any point you’ll have one packed with clean stuff and another of dirty stuff waiting to be washed.

  21. BraveFart:

    I couldn’t do without the dishwasher!

    I’m not one that does all the rinsing before it goes in – just bung it in, shut the door and get dry, sparkly clean stuff out later.

    My Sister-in-Law cleans everything before she puts it in which I agree seems completely pointless…

    Another great thing about them is you can use them to clean car parts and stuff. When I restored my Mini everything that could fit into the washer (engine parts, wheels, carb, etc.) went through the boil wash and came out clean and grease free… Mind you, Mrs. Barman was in the UK at the time…


    I’m not sure…

    The washing machine has a hose that just connects to an outlet so the elctronickery is all built inside… I’m not sure what the temp is from the solar panels but it is probably ‘too hot’ at this time of year…

    The dishwasher has a clever electronically controlled valve thing at the outlet end – not sure what is in it apart from the solenoid.

    I guess I could really check the manual and see what the temperature limits are…

  22. Does crap/grime affect how much energy they can absorb? If so, how often would they need to be cleaned? That would be an expensive, expert job.

  23. @Martin Audley,

    A long time ago I worked (as a contractor) for the first company to get a patent on modular solar-panels-as-roofing-material stuff. It was pretty interesting, but I recall the electrical connections were actually quite problematic.

  24. Bloke in Costa Rica,

    100m² is on the large side for a three-bedroom terraced house in the UK these days. The average new-build is just 86m² (925sqft).

  25. Rob:

    We normally do the dishes on an ‘Auto’ setting which (presumably) adjusts the heat/time based on how filthy it determines the dishes to be.

    Mini parts, and other things go on a fixed 70 degree cycle.

    It has a couple of filter arrangements at the bottom which I take out when I remember and remove peas, etc.

  26. I read somewhere recently that you are supposed to notify the Fire Brigade of the existence of a solar panel array on your roof as they cannot (typically) be easily stopped from producing electricity in the event of a fire…

  27. Bloke in Germany

    They’re much better now, providing the contractor actually connects to the hot water system. Bloody cowboys everywhere.

    The two bed houses only have one radiator. The u value is lower by quite away than the uk regs.

  28. Bloke in North Dorset

    “The modest three-bedroom house built in just 16 weeks on an industrial estate outside Bridgend in Wales cost just £125,000 to build and, said its Cardiff University designers, will let occupants use the sun to pay the rent.”

    Plus the enforced largesse, courtesy Ed Milband, of other energy bill payers who have been forced to pay for the excessive feed in tariff.

  29. BraveFart.
    I’m with you, I could never see the point of dishwashers. I was taught to wash as I go when cooking so don’t end up with a small cairn of utensils and pans in the sink. Plates and cutlery are a doddle on their own after a dinner party.

  30. According no the Jewson building cost calculator, £125K is about right for an “excellent build quality” 100 sq m 2-storey house in Wales. A “standard build quality” house would be about £93K. So not cheap, just not stratospherically expensive.

    The economics of things like photovoltaic roofs remain to be seen, of course. Personally I’m very sceptical about the 20-year life quoted for the solar cells. Is that 20 years to 90% efficiency? 50% efficiency? 30% efficiency?… and then there’s all the inverter crap to hook them up to the mains.

  31. @Arnald,

    “electrical connections” implies PV, not hot-water panels (which have been around for decades, if not millennia).

  32. I wonder how much cheaper it would have been without the solar panels, just having a loft conservatory helping to warm the house.

    The Guardian article has been edited but I can’t see any acknowledgement of this. It originally said: “Using batteries to store the electricity which it generates from the solar panels that function as the roof and more panels in the garden, and having massive amounts of insulation to reduce energy use in winter months, it should be able to export electricity to the national grid for eight months of the year.”

    The author appears to have assumed the massive solar array in the background was included in the price.

  33. I assume those eight months of the year are late spring/summer/early autumn. Isn’t this the time of least demand? So presumably prices are fixed to ensure that when they sell at a time of peak supply/weak demand they aren’t getting peanuts for it.

  34. BraveFart: “rinse before they go in”? “Clean up remaining shite after they come out”?

    What kind of crappy machine are you using?

    Get yourself one that works and forget all that nonsense.

  35. @GlenDorran

    ‘Or you could save on storage space and the effort of putting stuff away by having two dishwashers. At any point you’ll have one packed with clean stuff and another of dirty stuff waiting to be washed.’

    I thought of this ages ago. My wife says it’s a stupid idea, but she’s wrong.

  36. Bloke not in Cymru

    Having grown up in that part of the world I’d be surprised they can pay their way for 8 months of the year.
    It makes the Pacific Northwest area seem a positively balmy and dry climate in comparison

  37. Modern dishwashers work better if the plates aren’t rinsed first.

    And do you really think that filling a dishwasher is complicated ?

  38. Mind you, what happen in 20 years and the company that makes this material is no longer in business?

  39. @BraveFart: “rinse before they go in”

    One used to do that for 70’s/80’s dishwashers. As stated above modern ones (i.e. effective ones) don’t require this. I still do occasionally anyway, to get “the worst” off.

  40. Or you could save on storage space and the effort of putting stuff away by having two dishwashers. At any point you’ll have one packed with clean stuff and another of dirty stuff waiting to be washed.

    There speaks a wise man.

  41. Don’t PV solar panels need to be cleaned regularly to keep them working properly?

    And safety regs will now require full scaffolding to do that.

    The cost of that?

    (and I love the 2-dishwasher idea)

  42. @ Richard

    A friend of mine is a ‘Property Developer’ which mostly means here that he has inherited his father’s goat farm and built some houses on it.

    You can’t give away houses here at the moment so he is left with five finished properties and a load of empty land.

    Generous government (EU?) subsidies encouraged him to cover some of the land with PV panels. I told him he would have to spend lots of time cleaning them but he wouldn’t believe me.

    Now he keeps a ladder and bucket in the enclosure with the panels for the regular washing they require.

    I would have thought they could produce some form of ‘nano’ coating that would keep the panels clean in Wales where it rains all the time but here (when there is no rain between May and November) washing is the only solution…

    I often wonder how much output is lost from the arrays that are springing up all over the island due to the dust that covers them.

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