Eco housing stuff - terribly boring really

[El Pibe]

Ok, seeing as this place is full of know it alls, I was wondering if people knew everything about modern architectural practices and more specifically keeping carbon footprint low and energy costs down.

I'm building a house very soon, I have planning and am in the tendering process, meaning we're having to think very seriously about details now.

Most importantly is heat and energy sources.

I like the sound of geothermal energy, but am a little sceptical about some of the claims the vendors are making and am wondering if anyone knows what the real energy [electricity] costs are compared to say traditional gas or oil powered water heating and what the long term costs are in maintenance and replacement of pumps and so forth.

The place will have 10cm high density cavity insulation in walls, floors and ceiling with 30cm around joists, so we should be good at retaining heat. We'll have high quality insulation with the windows too.

Do people have any experience with solar thermal transfer and whether this might be viable on its own or in conjunction with another source. (there is about 18 metres of south facing wall we can harness and about 300 m2 of roof space.

THere are also 3 wood burning stoves and an open fire.

We're also looking at solar panels for electricity generation.

Any other alternative ideas we should be looking at? I'm completely open to suggestion as this is all pretty new to me.

I'd like to cook with gas out of habit, but first and foremost we want to have little or no dependence on fossil fuels for any of it (especially oil!!) and we do have an old aga we can plumb into whatever we do end up using.

Wow, I bored myself with that one!!

Bear in mind also this is far to the west of here in a place not known for being either a)warm or b)sunny.

*edited mostly for paragraphs and things*

[Huguenot]

There's NOTHING boring about that! :))

What a terrific scheme!

[steveo]

I feel guilty every time I have a bath these days. I try not to get too grubby, so often that water looks fairly clean when it goes down the plughole, and it's still warm.

Is it beyond the wit of man to re circulate some of the heat or the water... cheaply, without it going off the premises?

[El Pibe]

I think there are enclosed heat capture/retention systems, I'm sure this has been mentioned to me. I'd love to know what it entails and if I can implement it.

[Huguenot]

This seemed a reasonable third party review. The figures are high enough to be plausible...

"A geothermal heat pump system costs roughly $2,500 per ton of capacity, according to the California Energy Commission, so an average-size home using a 3-ton unit would end up paying $7,500 or so. Of course, you'll also have to include the cost of drilling to your tab; how much exactly depends on how your system will be positioned, whether it'll be wedged vertically deep underground or horizontally a shorter distance below ground. Drilling costs can fall anywhere between $10,000 and $30,000.

While a geothermal system costs more than a conventional oil- or natural-gas-dependent system, the cost of running heat pumps is actually 30 to 40 percent less than a conventional system that runs fossil fuel, meaning you'll be able to save enough on reduced heating and cooling bills to break even in two to 10 years.

Durable and almost maintenance-free because their components are sheltered underground away from the elements, geothermal heat pumps are guaranteed to last 25 to 50 years."

[Marmora Man]

Interesting stuff - we're planning to move from Marmora Mansions to the West Country and are debating at present whether to buy "ready made" or take on a project that can incorporate much of what you're suggesting. Don't know the answers to your questions as we're just at the beginning of our thinking - but I've always been a fan of geothermal having been party to installing it it in the NHS a few years back - massive savings over 50 years, tho' very high set up costs.

[Jeremy]

steveo - greywater (i.e. non-sewage waste) filtration/recycling systems are already available, as are waste water heat recovery systems. As for the cost - it looks like it will take you around 5 years to get your money back, which doesn't sound too bad.

[????]

There was a Grand Design recently where a bloke created a 'solar thermal' system I think, it was in Kent. He also had panels etc. Worth googling as I think he 'was' and enthusiast and pioneer and happy sharing experience and data on performance etc.

Ireland and sun though :-S

[El Pibe]

Cool, all good thoughts, thanks chaps.

'30-40% less' sounds more plausible than the '20% of' which was quoted to me (by a salesman obviously).

Of sloar energy, our architect says she runs her place entirely off the panels from march to october which is really encouraging (even in Ireland!!!).

[Undisputedtruth]

You will need to have a look at coefficient of performance for geothermal energy. There was a Telegraph article questioning whether it was cost effective to have airsource/groundsource pumps based on coefficient of performance compared to gas central heating.

There is a housing complex in Mitcham where they used ground source heat pumps for the past ten years. Worth a Google.

You may want to consider micro-chp as it's one of the most exciting heating technologies around. Basically it's a gas boiler which can generate electricity as well. The UK government predicts that 20% of homes will have them in the next ten years( ?) .

There is a new build on Camberwell Grove where the owner installed airsource heat pump, solar panels and strategically placed windows for solar gain. He sourced his heat pump from China for about ?2000. Saving himself ?6000 from not using British suppliers.

[*Bob*]

The above-generation of *Bobs* all have solar panels. It's terribly exciting, watching them scurry into action to 'put everything on' as the clouds part. Installation was timed with military precision to make use of generous subsidy grants and sell-your-leccy-back-at-guaranteed-prices though - the same deals are no longer available, I don't think.

I get a regular electricity production report from my Mother over the phone - which I obviously look forward to enormously.

A geo-heat-thing is also being investigated but I suspect they've worked-out they'll have pegged-it before it recoups the outlay.

[Ruairi]

Hi

Try googling Passivhaus. Its a German low energy standard that is gaining popularity in the UK and Ireland eco movement. The basic principle in a nut shell is to invest in insulation (more than what you suggest for your project) and airtight construction in conjunction with a heat recovery ventilation system. Then you?re left with a tiny space heating demand which does not require a conventional heating system, though you can have one if you want. Solar thermal is probably a good idea too, my parents in Ireland get most of their hot water from March-October from theirs. You can still have your bolt on renewables if you like, but not necessary, better off investing insulation. If your interested in Passivhaus ask your Architect (not to be confused with passive solar) he should have heard of it atleast. There is a whole certification process for QA, but it?s unlikely you will achieve this if the building has not been designed to meet the standard from the outset. You can still apply the principles though.

Ruairi

(Architect specialising in Low energy Design)

[El Pibe]

Our original London architect was very keen on passivehaus, for one reason or another we didn't go with him and went with a local one who frankly didn't know their arse from their elbow.

It'll be a very big property, about 450 m2 altogether with an odd configuration (double heights, single heights, height and a half bits) as well as sort of three wings based around a central glazed hallway. This is done to unite but stay true to the original buildings though we'll be levelling and efectively starting from scratch.

I'm wondering if passivehaus standard may be unafordable, or can we not afford not to...so to speak?

Not to take up too much of your professional time, and thanks for the feedback, but not really knowing anything is our insulation a decent standard, now would be the time to gt those changes in?

[nashoi]

Try googling 3 acorns camberwell, another local eco house and consultancy.

[Undisputedtruth]

I found the Telegraph article now.

[El Pibe]

Thanks UDT.

We do rather fit the bill for:

"Heat-pump systems ... might be worthwhile installing in new-build projects, as an alternative to oil or LPG (Calor gas) in country areas."

[Ruairi]

No problem, always happy to give some advice if I can. Depending how far along you are with the production of tender/construction drawings I would consider changing your Architect if your not happy with them. It will be difficult to achieve what you want otherwise, as the devil really is in the detail with these things.

Regarding insulation, a U-value is the measure of how fast heat flows through a component and the lower the number the better insulated that component is, (measured in watts/meter squared Kelvin). I am not sure what u-values you are achieving with your project, but as a rough guide for PH you would be looking at

Walls and floors 0.15 W/m2K

Roofs 0.10 WW/m2K

Triple glazed windows and doors 0.8 W/m2K

I would be aiming for this on most projects to start with.

Regarding the other items it is hard to give you much advise as things like the selection of a heating systems and renewable is very project specific and there is no one size fits all.

Hope this is some help

Ruairi

[Undisputedtruth]

El Pibe Wrote:

-------------------------------------------------------

> Thanks UDT.

>

> We do rather fit the bill for:

> "Heat-pump systems ... might be worthwhile

> installing in new-build projects, as an

> alternative to oil or LPG (Calor gas) in country

> areas."

Indeed, but it ends with a payback of 50 years and a net loss.

ETA: Can I take it that natural gas isn't available as well?

ETA: Curious to know if solar panels can supply enough electricity for ground source pumps during the winter period?

[El Pibe]

Thanks a million; so invest in the insulation first and foremost, sounds very sensible, I'll look into it.

[*Bob*]

Will you be keeping chickens?

[Ruairi]

No problem, also keep an eye out for thermal bridges (elements that bridge the insulation layer and conduct heat faster). These can have quite a big effect on the performance of your building. They should ideally be designed out so the construction is thermal bridge free, but this is quite difficult to achieve in practise.

[El Pibe]

Right, will do Ruari, I'm not convinced the architect will have even heard of them, thanks again!

With the state of the economy over there, quite possibly *Bob*, quite possibly!!

[Undisputedtruth]

Is Biomass an option? A few schools in Southwark uses them for their energy needs.

[Annette Curtain]

El P

Take a look at this magazine.

DWELL

(not to be confused with that shonky sh!te sold online)

NETTE(tu)

[LuLu Too]

My ex is a PassivHaus architect and has written quite a bit on the subject.

I can PM you if you want to google and read some online articles - lots of geeky technical details...

Also have you checked out www.phai.ie? The Passive House Association of Ireland - might have some useful info/contacts for your Architect.

Good Luck.

It will be worth it.