Eco house - school project facts required.

[teslacoils]

Half term. School have set a "design an eco house" project. Teacher is all ground source heat pumps, wood and turf rooves.

Is that right? Sounds dear and a pile of future problems. Surely over it's lifetime, concrete is perfectly good. What else do we need? Surely community heat and power better than a £30k ground source heat - could buy a house in Greece for that and live their in winter.

Eco house? Trendy fad is it - will the future be wicker wigwams, or underground concrete megacities?

 

[D14]

Half term. School have set a "design an eco house" project. Teacher is all ground source heat pumps, wood and turf rooves.

Is that right? Sounds dear and a pile of future problems. Surely over it's lifetime, concrete is perfectly good. What else do we need? Surely community heat and power better than a £30k ground source heat - could buy a house in Greece for that and live their in winter.

Eco house? Trendy fad is it - will the future be wicker wigwams, or underground concrete megacities?

Eco houses in Germany that are now pushing 20 years old are in very poor states of repair. I've been looking into it for a proposed development here where we can only get planning for eco houses due to the location of the site. The main issue is that on any new development you need to get the NHBC warranty for the structure and extended warranty on the heat, waste systems etc. So we can either do that in our own name or if we use a developer they do. Either way you're potentially looking at far more claims than a standard house. We've built a few small developments over the last 30 years so have an idea of ongoing claims etc. I'm actually thinking its not worth the hassle to be honest.
Also from a buyers point of view when it actually comes down to signing on the bottom line a high percentage blackout because they know deep down a traditional house is a safer bet.
What we should be doing as a country is like you say putting community heat and power systems into villages.

 

[teslacoils]

Thinking - we all need Eco houses
Reality - eco houses are really daddy gimmicks requiring big rhi handouts, really for the rich to use to crow about how ace they are.

However, for my child to get any credit for pointing this out it needs to be properly researched rather than my instinct.

 

[DrWazzock]

I'm inclined to agree. I don't think burning anything is the way forward if I'm honest. If we all ran log or biomass burners the smog would be bad and there is still the NOx and unburnt nasties. Its got to be nuclear at the core, maybe solar and wind but really they are huge users and creators of plastics and crap that will never breakdown for a pretty unreliable low density source with a fairly short design life. Landfill will be heaving with bust solar panels within 20 years.

If only high rise living could have been made to work from the social point of view then it would have afforded big savings in heat loss and land usage. High density accommodation is inherently better for reducing heat loss with less surface area to volume per inhabitant and also reduces traffic for waste disposal and other services. Put the offices or factory or entertainment or shops in the basement and nobody needs a car that much either. High rise living. They were nearly getting there with that in France. It wasn't that bad actually.

Underground housing at least affords stable temperatures. Weld up a stainless steel tank, insulate it well and you probably wouldnt need heating or air con at all. Body heat would be sufficient. Recover heat from expelled stale air to heat incoming air although this process can never be 100% efficient. And you leave the ground space for a solar panel to top up your system with the little energy it does need. Maybe low rise is the answer? Dig in far enough and you benefit from geothermal heat.

There is a huge amount that could be done if planning rules and social conventions were a bit more flexible.

I'm inclined to agree that "eco" houses are just a scraping the surface really. It needs a radical rethink. In the medium term there is a lot to be said for make do and and mend, repair and improve until such time as properly engineered radical solutions can be rolled out. You are up against human behaviour and tradition though.

Put in a planning application for a high rise development with a nuclear reactor in the basement. Design life 200 years minimum.

Lets go forwards, not backwards. It has to be a solution that takes account of the masses, not just rich rural good lifers with income from elsewhere. It has to fit a lot of people into a small space.

 

[Ffermer Bach]

I think there is a awful lot of embedded energy in concrete, if I had a blank slate to design an eco house, I would look towards cob or straw as a building material, finished with a lime render internally and externally. I would tend towards a timber frame with straw infill, rather than structural straw walling.

I personally dislike turf or sedam roofs (as I think they don't look good), and I am guessing an eco house should have few windows (I know big picture windows are popular now), windows that are there should face south and the sunlight should fall on a large thermal mass to store the heat. Maybe a tin roof, with rainwater saved for washing etc.

I am not sure about either ground or air source heat pumps, I dislike anything with too much technology to control it (more wires, more chance of it going wrong), but I guess of the two I would go ground source, but with good insulation (sheep wool in the roof? And I keep Easycare/Exlana!) not much heat is needed, so maybe a wood burner (if the government does not ban wood burning).

Limecrete floor with good insulation, maybe using foam glass insulation too.

Composting toilet too I guess.

 

[Exfarmer]

I used to live in a mud brick house called clay lump round here. Not sure of the insulation value but the blocks themselves have low environmental cost just straw and locally sourced clay. This I think combined with a lime mortar gives a very long lasting structure. A lot of mine was 200 years+It must be kept painted though every few years. The next bit is possibly not so good as they used to use straw in the walls for insulation which is both. a fire risk and rodent heaven. However like all good insulation companies you can gloss over that bit.
Clay lump is structural so it would be a good start

 

[Highland Mule]

Insulate, seal, add mechanical heat recovery. Done properly you need no heating and can get all the input energy you need from the inhabitants, the telly and a bit from cooking the Sunday roast. A modern Eco house has no need for any heating. For hot water, solar thermal panels on the roof, suplemented by a simple immersion heater for cloudy days and high demands. The upfront energy that would go into making a heat pump would go a long way to the first few years of heating, before you even consider running costs.

 

[How much]

An eco house would surely be made as much as possible from wood , which is basically insulating and renewable add to it insulation in some form ideally a one that is less polluting but effective . Wool for example would be ideal but costly and not suitable for upright surfaces ,expanded foam very good insulation but not as environmentally friendly so probably a mix of both
keep the whole thing tight fitting and well built with minimum air loss , no gaps or drafts
then orientate the structure so it does not get either to hot in the summer or to cold in the winter , and add some solar panels , a rain water recovery system and heat recovery ventilation system .
And you have am eco house.
If you goggle passive house that is maybe even a step further but a basic starting point would be a wood frame I think

 

[Highland Mule]

a rain water recovery system

That would be a waste of plastic pipe up here! Just shows how priorities can differ across the country.

 

[Exfarmer]

Dont forget seperation of grey and sewage water. Recycle the grey as much as possible

 

[SilliamWhale]

Straw bale?

 

[GeorgeK]

If you want to get the top marks in education you have to tell the assessor what they want to hear. No point in going against the grain even if you're right, the teacher is human and as such is vain and petty like the rest of us, they need to be praised and told how right they are not the opposite. To get the A* it's licky licky brown nose time, discuss the topic with the teacher under the guise of an 'informal chat' then regurgitate the information back to them.

 

[holwellcourtfarm]

Insulation, insulation, insulation. The biggest eco cost of a house after the embedded energy creating it is heating it. Get the insulation right and you've cut 90% of future energy use.

Have a look at Passivhaus for commercial ideas and, for the truly "outside the box" ideas search Earthships.

Do look at water use too though. Many of England's water companies are now recognising that they face a problem maintaining supply as we waste so much. Here in the South East it's led to rivers drying up. Add in rainwater harvesting and greywater recycling to flush toilets and water gardens.

 

[Exfarmer]

Insulation, insulation, insulation. The biggest eco cost of a house after the embedded energy creating it is heating it. Get the insulation right and you've cut 90% of future energy use.

Have a look at Passivhaus for commercial ideas and, for the truly "outside the box" ideas search Earthships.

Do look at water use too though. Many of England's water companies are now recognising that they face a problem maintaining supply as we waste so much. Here in the South East it's led to rivers drying up. Add in rainwater harvesting and greywater recycling to flush toilets and water gardens.

The problem is that water companies will never encourage rainwater harvesting. The big cost of the water system is the sewage and thr cost of that is based on the water the house buys in.
However it is absolutely crazy sending fresh pure water into the sewage works

 

[Exfarmer]

If you want to get the top marks in education you have to tell the assessor what they want to hear. No point in going against the grain even if you're right, the teacher is human and as such is vain and petty like the rest of us, they need to be praised and told how right they are not the opposite. To get the A* it's licky licky brown nose time, discuss the topic with the teacher under the guise of an 'informal chat' then regurgitate the information back to them.

While you have a good point, teachers do like to see children have done research and challenging conventions by quoting facts, even if they dont match the prevailing thought, is a sign of a bright child.
Not sure how many kudos , they will get cutting and pasting from this forum though

 

[holwellcourtfarm]

The problem is that water companies will never encourage rainwater harvesting. The big cost of the water system is the sewage and thr cost of that is based on the water the house buys in.
However it is absolutely crazy sending fresh pure water into the sewage works

Have you seen how much WRSE predict spending to secure future raw water supplies? They admit they'll be around 140mld short by 2030 in their best case scenario.

 

[Gareth J]

Was an interesting grand designs a couple weeks ago, a couple built a house within a massive mound of earth, open faced to the south with lots of glass there. Then, insulated and plastic covered on top of the mound, with another layer of earth/turf on the very top. Insulation extended beyond extents of house well into the garden.

The principal was inter-seasonal heat storage. A couple years in and the whole ground and building would sit at a comfortable temperature.

That was a typical GD project though so couldn't really be hailed much as "eco" just because of the scale. But inter seasonal heat storage is interesting and to design/build a building with not only barely any heat input but also minimal mechanical wizardry that is both expensive to buy and maintain and is relatively short lived was impressive.

 

[teslacoils]

We've shortlisted to:

Essentially a hobbit hole, in the ground, straw and mud, with light tubes for lighting the mostly windowless rooms. Compost toilet, rain harvest etc. The idea being the lifespan in short but the whole place bar a few bits and bobs can essentially be composted. This is interesting because my "pioneer" relatives who moved to the states in the 1800s lived in houses dug out of the soil and built with turf blocks.

Urban planned concrete / aircrete / hempcrete mini cities with communal kitchens, waste and grey water recycling on site. Expensive structure but long life, minimal repairs, no need to leave. An urban version of the Bruderhof.

 

[DrWazzock]

It’s an aside but how do folk get on with rodents in straw built houses? We get a few and sometimes a squirrel without encouraging them. Every so often you will be lying in bed at night and you hear something scuttling over the ceiling. Time for step ladder and the rat bait.

 

[teslacoils]

Not sure if the Eco mud hut requires eco lifestyles too. Or do you just do it to claim the rhi sub and when it gets nippy fly off to Barbados....