Parents are looking at building an eco house!

[Thurston Garden]

My folks have an acre of garden just asking to be built on. They had their architect round this week as they have been mumbling eco house for a while now.

The architect is very enthusiastic but was talking about pv/turbine/ground source heat pump but to be honest I am not so sure.... my folks are in their 60's and are unlikely to see the financial return on the outlay.

I am trying to steer them to a smallish straw bale structure, cleverly designed to make optimum use of the sun (it's a south facing site anyway), minimise wasted hot water in pipe runs, recycle rain water and built from local materials.

Could be interesting!

[ina]

One couple on NEEPS have just moved into their passive house... They have neither a wind turbine nor a ground source heat pump, but still rarely need to heat (they have a woodburner for top up - also for water, which mostly runs of solar heating). If you want to check out what they've done, you can find some of their experiences on neeps.co.uk (James and Jessica).

[Thurston Garden]

Thanks Ina -quick reply! I think my folks will enjoy a bit of inspiration - they are in the very early stages.

If it was for me, I would have a 12v leccy system, be off grid and have a wood burner. I am not so sure about a wood burner for pensioners though.

[ina]

That's a consideration - but they could have an immersion heater for the water, and some other form - maybe gas? - for extra heat in the living room or so. J&J's house is usually about 17 degree C - without any heating, in winter!

[Thurston Garden]

I have emailed Mum J&J's blog link. I am sure they will enjoy looking at it.

There are so many things in the paper/mags/tv that have got them thinking that they need to be going all out to have the best/most env friendly building, but I think they should just insulate to the max, minimise their pipe work esp on the hot side, re use roof water for flushing/WM, install A+++ (or what every they are now!) appliances and use local/sustainable materials where possible.

Anything has to be better than the two of them in a 4 bed 70's bungalow!

[witch way?]

Having experienced being off grid and totally self sufficient for power and heat and now thinking of my 'old age', my thinking is coming round to using 'green' methods wherever posible but having conventional back-up systems. I suppose in particular I'm thinking of heating. When it all works its a great feeling, but when the weather's been bad for a few weeks and the solar powers down and then you find the wood's all got damp too or the flue's caked up and needs clearing it can be pretty miserable. When you're young, fit and healthy, not too much problem but if your parents are getting on then frailty has to be considered and of course one may have to live there for a time on their own. Oh dear this post sounds really negative and Im tempted to scrap it but its a huge comitment and it would be such a shame if it turned out to be uncomfortable for your parents. That's not to say dont do it but just to bear this aspect in mind. However you all decide to do it, have fun and enjoy. W.

[Thurston Garden]

WW - yes, I totally agree. If they were in their youth, then they probably could go all guns blazing at it, but they intend that the house shall be their last, so very careful planning is going to be required to ensure that it meets their needs now and their needs and abilities for the next 20/30 years.

I do see them being hooked to the grid, and more than likely having mains gas, but as long as the building is designed properly, then the consumption of both should be at an absolute minimum.

[Martin]

I think I'm closer to your ideas than the architect's!
I'd go for a "passiv haus" design, whereby by careful design and building, the property needs very little in the way of heating.
Unless you're generating a lot of your own electricity, I'm not a fan of heat pumps - to run them off the grid is prohibitively expensive (the salesmen gleefully go on about the 3 or 4 "free" heat units, but neglect to mention that the unit you have to put in is electricity - the most expensive form of energy!)
I'd add a relatively simple solar hot water system for domestic hot water in summer, and probably suggest some pv panels (the electricity generating jobs) - they're pricey, but "fit and forget", and if you design to use very little electricity, you don't need a vast array.
Possibly a small wood pellet boiler for winter (auto feed job)
As to them "not getting the benefit", if they've made it to their 60's, they could be around for another 30 years.......and I think that any sensible outlay on renewables will always add to the intrinsic value of the property
(and increasingly so, as fuel prices skyrocket)
IF the site is suitable for windpower, it MAY be worth looking at the heatpump option, but it will cost a shedload more (I wouldn't go for the heatpump unless generating the electricity for it - it'd cost-effective with a well-sited turbine, but not using pvs, the cost would be prohibitive)
If possible, always try to avoid immersion heaters (except as emergency back-up), they use horrendous amounts of the most expensive form of energy - and it certainly won't get any cheaper!
ps, if they've got mains gas, for the time being it's the cheapest form of energy - have a small efficient gas boiler instead of the wood pellet job!

[Thurston Garden]

Thanks Martin - pleased to hear I am not wildly off the mark. They won't want to spend a shed load of cash on a development, but what is spent will be spent wisely.

I am not sure whether a turbine will be possible - the site is on the edge of a conservation village and has a number of trees in it - it does get the wind mind! Noted on the gshp though - a good argument for when the architect proposes it. Mind you, the location he is suggesting has about half an acre of nice flat lawn in front of it, and backs into a (man made) hillside about 25ft tall. Next time I am there I should take a photo.

They have two options for site - the one mentioned above which screams out earthship and a plot above this with grand views which could take any style of house in the normal manner.

I am slowly drip feeding them with links to useful websites, so if anyone has any to contribute, I would be delighted to see them!

[Martin]

If you'd like to pm me the post code of the site, I can look it up on the NOABL database to give you a rough idea of viability for a turbine
(mind you, two words tend to suggest you're onto a loser - "trees" and "conservation")

[Martin]

from the postcode, it's suggesting an estimated 5.3 m/s at 10 metres above ground level (typical small domestic turbine tower height) - which means it's certainly a viable proposition IF that is born out in practice........
- however, this assumes that we're talking 10m up, in the middle of a field, with a "clear fetch" in the direction of the prevailing wind of several hundred yards (no buildings, fences or trees)..........
You mention being sheltered from the prevailing wind by mature trees........I'd say it's almost definitely a "forget it" job.........anywhere within a few hundred yards any obstruction induces such turbulence as to render the installation a "no go". I'll try to explain...........
To work properly a turbine needs to be able to stick it's head into the wind and rotate without interruption for long periods - any obstruction puts "lumps" into the air which means that the poor old turbine is starting and stopping, and "hunting" for the wind (swivelling round on the tower).......
Under the G83 standard for grid-tie, there has to be a synchronising rhumba between your turbine, and the grid before it can connect to export electricity - this is 3 minutes - in turbulent conditions, it seldom happens!
(By the time a minute or so has gone by, the wind drops momentarily, and it has to "start all over again")
Should they opt for a battery bank (unlikely), there are similar problems with intermittency!
It's very frustrating, because often there are really strong "gusts" on a site like this which gives the impression that there is lots of wind - there is, but it's not useable wind! (too many "lumps")
Hope that makes sense!

[Thurston Garden]

These two have some very valid points!

[Martin]

They talk a great deal of sense - particularly "insulate till it comes out of your ears, then insulate some more"....
It really is common sense - the less energy you have to use to supply your home, the less you have to buy or generate...
Which is why I'd recommend some pv panels - they are blessed expensive, but if you design to use very little electricity they make a lot of sense...(fit and forget, and very easy to accurately predict their output). With a new build you have the luxury of a clean sheet of paper, and you can insist on low-consumption everything, from tvs and computers through to fridges and washing machines.
As for grants, I've ranted enough about them in other threads - they're a farce, badly targetted, hopelessly wasteful of resources (£600 to "administer a £400 grant).........etc, etc

[Thurston Garden]

Does PV = 240v, or do they need battery bank and an inverter?

I have had a scheme in my head for sometime where the house (mine in the future that than parents one) would be 12v but have a mains supply to an adjacent garage/workshop where heavy items such as a washing machine would be connected to the grid. This would allow for exporting in times of peak, and using the grid when I could not generate or the store had been used up.

[Martin]

Pvs can be used for either (or both) - single panels usually come as 6, 12 or 24volts - they can then be wired in series or parallel or a combination to give virtually any voltage you want, and it often makes a lot more sense to have something like a 48v battery bank, especially for a largeish one, when it's going to be used to provide "mains power" through an inverter......(its the old volts times amps thing) - in simple terms, if you have a thundering great battery bank connected up as 12v, and you want to take a hefty load from it (an inverter supplying a couple of kilowatts for instance), at 12 volts, that's something like 160 amps - you'd need cabling thicker than your thumb (thicker than car battery cable) at 48 volts, it's a more manageable 40 amps, and still large, but a lot thinner and cheaper cabling . The current produced by pvs is DC, all domestic appliances need 240v AC, so you will need an inverter
You've got 3 choices -
Grid-tie alone - you have an "export meter" as well as your normal tariff meter - in summer, when you're producing more than you're using, it's exported to the grid, and you're paid for it - in winter, when you're using more than you're producing, you pay for it normally - size it right, they cancel each other out (you're effectively using the grid as your battery)
Battery bank alone - a more expensive option to set up - a large battery bank is expensive, and has eventually to be replaced, but it does give you independence from the grid. Generally pvs are supplemented by wind, as when you need most electricity (winter), pvs are producing least, and winds tend to be at their highest in winter.
A combination system of a battery bank to give an emergency "reservoir", which is also grid-tied..........(quite an expensive option, but a nice "fail safe" one)