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ebuild is sad to announce its closure - it has become too time and resource intensive to develop, manage and maintain.

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Zero Carbon Homes Officially Dead


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#21 ferdinand

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Posted 12 July 2015 - 06:34 PM

Having had my miniscule rant :P lets be helpful.

Required:

- Overall energy standard.
- A focus on the house and living in it for 50 years, rather than on umpteen other short-term things shoehorned in because they are fashionable or can be seen while it is being built.
- Enforcement.

Think I'm inclined to drive it from Building Regs, and it suggests a focus on boring things that work:

- High quality fabric.
- Lots more solar panels.

Less provision for cars (said the utility cyclist), but for for 'ZEV's?

Two gimmicks I would like the aim of is:

- if the developer was liable for a significant minority of energy bills for the first decade
- stamp duty rated to energy efficiency.

The first of these could actually be a marketing thing, like free insurance for cars.

Can we outlaw Greenpeace?

What would the benefit be if we actually started replacing our aged housing stock?

Ferdinand

Edited by ferdinand, 12 July 2015 - 06:40 PM.


#22 Triassic

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Posted 12 July 2015 - 06:51 PM

official figures showed new house building fell by 5.8% in May, the sharpest decline in nearly four years.

The Government fiddles as Rome burns!

#23 ferdinand

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Posted 12 July 2015 - 07:17 PM

View PostTriassic, on 12 July 2015 - 09:14 AM, said:

So where do our building standards sit against the rest of Europe?

That work is always being done, but from lots of different angles - the main two that I have seen being:

1 - Energy required for a dwelling, given building standards in different countries.
2 - Estimate characteristics required in a dwelling in different countries.

Let me see...

Excellent context: Comparisons of existing housing stock:
http://www.arct.cam....t_download/file

Ferdinand

#24 jsharris

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Posted 12 July 2015 - 07:18 PM

All we really need is to do what a lot of people have been saying for years; build houses with a "fabric first" approach and very rigidly enforce fabric standards.

Forget about carbon, offsetting, wizardry like heat pumps and solar panels, and enforce high standards of insulation and airtightness.

People can then do as they choose with heat pumps, solar panels, and all the rest, as all that stuff will be dead within a generation and need replacing. If the basic fabric of the house has low heat loss (and gain in summer) then all future generations have to worry about are the technology add-ons, not the fundamental structure of the building.

Well over 90% of our stock of dwellings suffer from very expensive to fix failings in their basic structure. We are bodging our old housing stock with loft insulation, cavity wall insulation, improved glazing, but even then we're still left with pretty crap housing, because some things just cannot be fixed economically, and it's cheaper to knock the house down and start again, which is crazy.

Our current house is pretty typical. It was built in 1982 and is typical of houses of that time. It has solid concrete floors, with no insulation under them, so the floors are always cold. It is built of block and brick, and has the positive feature of being wet plastered on all the walls, so airtightness is better than most newly built homes (and tested to prove that). Is has 300mm of loft insulation (originally 100mm between the ceiling joists, I added an extra 200 mm crossways across the joists). It has 50mm of EPS bonded bead cavity wall insulation, the best I could do. The original 12mm (4-4-4) double glazing was replaced 8 years ago with 28mm 4-20-4 double glazing, with a low E coating on the inner face of the outer pane. Airtightness was improved by the double glazing and new doors having far better seals than the old timber doors and windows, that had no seals at all. I spent hours sealing up the wall to ceiling joints, following a blower test we found LOTS of air leaks on every wall to ceiling junction (it's a bungalow). I sealed up and insulated the loft hatch, replaced the old toilets with their external overflow pipes (and cut off the old overflow pipes and filled them with squirty foam).

Some may argue that this was a lot of work to do to a 20 year old house (which it was when I started doing this), but I only reduced the heating requirement by around 30% by doing all this. The biggest gain was when I decided to replace the old wall mounted gas boiler with a condensing combi boiler and got rid of the hot water tank. At the time I thought most of this saving came from the boiler, but now I think a large part was probably removing the hot water tank.

Even now I have a 98m3 house that costs around £1200 a year in energy costs to run. Compare that to our 130m3 new build that needs no energy to run, in fact generates a lot more energy than it uses over a year. What's more relevant is the fabric will remain zero energy for the life of the building, hopefully several generations. The sexy bits of technology will wear out, break and need replacing, but that doesn't matter, as they can always be replaced as newer stuff come along. The main thing is that the fabric of the house won't need improving, it's good enough to last for generations.

#25 ferdinand

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Posted 12 July 2015 - 07:21 PM

But very little ever changes :-), and it all makes minimal difference in terms of energy.

Not sure how to interpret this. Perhaps people are warmer and have more space for the same energy, that is it has gone into more comfort not less consumption. Where have we heard that before?

Attached File  residential-energy-consumption-europe-comparison.gif   55.23K   15 downloads

Source:
http://www.tyndall.a...iles/twp155.pdf

Ferdinand

Edited by ferdinand, 12 July 2015 - 07:23 PM.


#26 tonyshouse

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Posted 12 July 2015 - 07:30 PM

Looks like it is latitude dependant

#27 SteamyTea

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Posted 12 July 2015 - 10:39 PM

I do seem to remember reading that our houses are warmer than they used to be.
We also have lower energy TV's, PC's, Fridges, Freezers these days (though there is still legacy stuff).

#28 ferdinand

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Posted 13 July 2015 - 09:14 AM

There are quite a few reductions of 10% or so between say 2000 and 2010.

To me the main messages are a) The inertia of old housing stock and b) How little difference years of flobulating from politicians and think tanks makes.

Things can be done, but it would take a generation for real change - say a fall of 50% in domestic energy use.

Ferdinand



"b)" reinstated from emoticon. If the b) is used then make sure you're using Full Editor with the emoticons un-checked.

Edited by joiner, 13 July 2015 - 09:18 AM.


#29 ferdinand

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Posted 13 July 2015 - 09:17 AM

View Postjsharris, on 12 July 2015 - 07:18 PM, said:

Even now I have a 98m3 house that costs around £1200 a year in energy costs to run. Compare that to our 130m3 new build that needs no energy to run, in fact generates a lot more energy than it uses over a year. What's more relevant is the fabric will remain zero energy for the life of the building, hopefully several generations. The sexy bits of technology will wear out, break and need replacing, but that doesn't matter, as they can always be replaced as newer stuff come along. The main thing is that the fabric of the house won't need improving, it's good enough to last for generations.

Interesting number.

Ours is 175sqm which costs £1500 a year or so, and is a refurb/doubling of a 30s bungalow down to 3 walls and the floor up done in 2008 to quite high standards. 2 of us live here, and a cat.

Ferdinand

#30 SteamyTea

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Posted 13 July 2015 - 09:26 AM

Jeremy
If you had to import all your energy, do you know what your new place would use? I know it is a bit hard as you are not actually in there yet.

#31 jsharris

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Posted 13 July 2015 - 09:28 AM

View Postferdinand, on 13 July 2015 - 09:17 AM, said:

Interesting number.

Ours is 175sqm which costs £1500 a year or so, and is a refurb/doubling of a 30s bungalow down to 3 walls and the floor up done in 2008 to quite high standards. 2 of us live here, and a cat.

Ferdinand

Our problem is that I couldn't fit EWI (in a conservation area) and didn't want the hassle of digging up the floors and replacing them with added insulation, as we knew we weren't going to live here for long. Just fitting EWI and insulating the floors would get rid of most of our heat loss (and doing the walls would massively reduce our summer heat gain, which is actually a bigger comfort problem for us).

Fitting internal wall insulation would have made already small rooms too small (it's a three bedroom bungalow with a poor internal layout, with odd-shaped rooms and small bedrooms). I suspect there are a lot of similar properties still being built that are going to be equally hard to improve thermally, with the possible exception that they may have a bit of floor insulation.

#32 jsharris

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Posted 13 July 2015 - 09:29 AM

View PostSteamyTea, on 13 July 2015 - 09:26 AM, said:

Jeremy
If you had to import all your energy, do you know what your new place would use? I know it is a bit hard as you are not actually in there yet.

Probably around £300 to £400 at a guess. It is very much a guess, though, as the meter doesn't record at all most of each day for a large part of the year, and around 20 to 25% of the energy cost is the standing charge, rather than energy usage.

#33 gravelld

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Posted 13 July 2015 - 09:44 AM

View Postjsharris, on 12 July 2015 - 07:18 PM, said:

Even now I have a 98m3 house that costs around £1200 a year in energy costs to run.
That sounds an awful lot.... and I must say that what you say about your efforts not meeting much reward is rather demotivating! :(

Got any measurements on that, and what you did? I'm also sealing a lot of wall/ceiling junctions albeit on a two storey house. I'm not expecting massive gains but it's such a pain in the arse in the eaves, fudging a nozzle for the foam etc etc you kind of hope something will come out of.

#34 jsharris

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Posted 13 July 2015 - 10:05 AM

View Postgravelld, on 13 July 2015 - 09:44 AM, said:

That sounds an awful lot.... and I must say that what you say about your efforts not meeting much reward is rather demotivating! :(

Got any measurements on that, and what you did? I'm also sealing a lot of wall/ceiling junctions albeit on a two storey house. I'm not expecting massive gains but it's such a pain in the arse in the eaves, fudging a nozzle for the foam etc etc you kind of hope something will come out of.

Our main problem is heat loss through the walls - 50mm of EPS bonded beads isn't great when it's your only wall insulation, and heat loss through the solid concrete floor. This floor heat loss is exacerbated by the central heating piping running in a ring around the whole outer edge of the floor slab, with all the rads except one being against an outside wall. The plumber obviously thought that setting a pair of copper pipes in a big circuit right in the outer edge of the concrete slab was a good idea, as it made for a neat installation, but it does waste a heck of a lot of heating energy. It also causes problems whenever I need to replace a radiator, as newer rads are always a different width and the two I've needed to replace so far have caused much angst as there is no way to easily shift where the pipes come up through the floor.

I got my air leakage down to around 18m³/m² @ 50Pa, with a lot of effort in sealing things up, mainly getting the plasterboard ceilings to seal to the walls. My main airleaks now are the patio sliding doors (they have reasonable seals, but not great) the letter box and around the sealed loft hatch (which despite my efforts howls like a banshee when my home made pressure test fan is running). The sealant around the wall to ceiling joints is failing (I used acrylic, as I needed to paint over it) as I can see black lines where loft dirt is being drawn in through these very tiny gaps again.

#35 gravelld

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Posted 13 July 2015 - 10:32 AM

Thanks. I find acrylic sealant rarely works except in the best case situations. Any movement at all and it cracks. Polymer is my favourite these days.

Were the junctions not covered in coving - couldn't you flexifoam it from the loft? Might depend on the roof angle.

Would hate to think what we would score.

That floor situation sounds like a worst case scenario really!

#36 jsharris

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Posted 13 July 2015 - 10:54 AM

The problem was air leaks from every single wall to ceiling joint. The internal walls are plastered block and they tend to leak to the loft space the worst, presumably because the whole ceiling flexes upwards slightly, as it just rests on the internal walls, as far as I can see. The loft space is very well ventilated, because after I fitted the extra lost insulation we had a big condensation problem up there, with the sarking felt dripping wet in winter and forming puddles on the plastic lining of the "anti-itch" insulation I'd laid. Some of these puddles ran off and stained the ceilings beneath it was that bad. I fixed the condensation problem by adding a lot of soffit ventilators, but that then made the ceiling to wall leaks worse.

I think that if we were staying here then I'd have put a good bead of polymer sealant around and covered it with coving, as that would probably permanently fix all the leaks, but it hardly seems worth it when we;re about to sell up.

You're right about the floor being a worse case. As far as I was able to track things, the plumber ran two circuits of 15mm (could even be 22mm) right around the house periphery, one for the flow the other for the return, and connected these to tees at each radiator, with the 15mm pipes for each rad poking up through the concrete floor. In the kitchen there are two 22mm pipes coming out of the floor in the corner for the flow and return to the boiler, that I think are tee'd to these two "ring mains". These used to run right up the wall into the loft, where the old header tank, pump, three way valve and wiring centre was for the old boiler. The old boiler had the flow and return running up through the ceiling to connect to the pump and three way valve, with additional long lengths of 22mm pipe running as the flow and return to the hot water cylinder fitted in a cupboard at the other end of the house. The new combi connects to the wall-mounted 22mm flow and return pipes, via a magnaclean filter on the wall. You can feel where the radiator pipes run around the edge, as the floor gets warm over them, as that's how I worked out that there was a sort of "ring main" set up down there.

Edited by jsharris, 13 July 2015 - 10:56 AM.


#37 gravelld

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Posted 13 July 2015 - 12:11 PM

Did/do you have coving? Wondering how tight that is, assuming no gaps can be observed obviously.

#38 daiking

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Posted 13 July 2015 - 12:27 PM

Not particularly bothered by zero carbon homes but this thread has been enligthening. Thanks.

#39 jsharris

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Posted 13 July 2015 - 03:27 PM

View Postgravelld, on 13 July 2015 - 12:11 PM, said:

Did/do you have coving? Wondering how tight that is, assuming no gaps can be observed obviously.

No coving, except in the bathroom, where I added some slim coving to allow a thick bead of polymer sealant to go all around the wall/ceiling joint, primarily to help the loft condensation problem, by keeping moist air out of the cold loft space.

Had we been staying here then I'd have done all the rooms, but compared to the heat loss from the daft central heating pipe runs the effect would be small.

Those pipe runs have an interesting effect when it snows. The first heavy snowfall after I'd fitted all the extra loft insulation, I went outside to compare the snow on our roof with that of our neighbours. Our roof had a thick layer of snow showing that the insulation was working well, but the 18 inches or so of ground all around the house was snow-free. The heat leaking out from the central heating pipes all around the outer edge of the slab was doing a great job of melting the snow. We also have some bluebells and snowdrops that grow against a wall. The come into flower weeks earlier than those in open ground, thanks to our soil heating system!

#40 Volcane

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Posted 26 October 2015 - 10:32 AM

Irish slant on passive construction, Dun Laoghaire council being challenged by central government http://www.irishtime...ouses-1.2405693