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What makes a house an eco-house (in Britain)? November 7, 2011

Filed under: Britain,Politics of building,Project outputs and findings — naturalbuild @ 9:11 pm

I have recently started work on creating a publically accessible database of eco-houses. I want to help publicise the diversity and creativity of eco-building. I have previously defined an eco-house as a building which minimises resource use (in construction and life -cycle) while also providing a comfortable environment in which to live. Yet this is quite vague and avoids having to really determine when a house is ecological enough and when it is not.

It seems like a really simple thing to do and there are numerous standards by which eco-houses are measured (such as Code for Sustainable Homes, AECB and BREAM Eco Homes). However, my concern is that as soon as a checklist is created some really innovative buildings are excluded and others do just enough to reach the standard but miss the bigger picture of what an eco-house is. So I want to find a way of defining an eco-house that includes the sheer diversity of eco-buildings we have in Britain (the database is starting with a focus on Britain and will hopefully expand later).

It needs to include a self-built low impact development using straw bale, just as much as a high-tech developer-built home. I need to find a simple set of criteria which I can use to determine what homes should be included in the database. It needs to be simple in order to be open and accountable to users, and to be as inclusive as possible while also setting a high bar as to what an eco-house should really represent. I have devised a list whereby if a house has any one of the criteria below then I consider it to be an eco-house:

  • Reduce energy use in some form (i.e. ground source heat pump)
  • High level of insulation
  • Use of renewable technology (photovoltaic’s, solar water heating, wind turbine)
  • Solar passive design (or shading)
  • Extensively used reclaimed or recycled materials
  • Reduces waste produced (for example eco-sewage systems or recycling of brown water)
  • Double or tripled gazed windows with a U value of 1.5 Wm2k or lower
  • Low carbon or zero carbon house
  • Rainwater harvesting or water collection systems, low water-use appliances, reductions in run-off
  • Deliberately small or compact design to reduce resource use
  • Green or grass roof for increased insulation
  • Grass roof for wildlife
  • Use of ecological materials like adobe, straw, sheeps wool, hemp, sand bag, reclaimed bricks, or wood (if FSC or reclaimed)
  • Passivhus standard
  • Deliberate avoidance of using environmentally damaging materials (such as concrete, lead, bricks etc)
  • Built using locally available materials
  • Heat recovery systems
  • Level 5 or 6 Code for Sustainable Homes
  • AECB Silver or Gold Standard
  • BREAM Eco Homes Standard level ‘Excellent’
  • Energy Performance Certificate (EPC) Rating A
  • Air tightness of less than 5 m3/m2hr (air movement) at 50 Pa

I would be interested to hear people’s opinions on this list and whether it is acceptable to enable buildings to be considered ecological by doing just one of the above. There are obviously important relationships between these criteria. For example, installing photovoltaic’s on a poorly insulated house is not very efficient, just has having highly insulated walls but low quality windows reduces the effectiveness of the insulation. However, to account for the relationships between these criteria significantly complicates defining an eco-house. There are an infinite set of possibilities available as we redesign our homes, but how do we define in an age of such building diversity when a house is an eco-house?

[7th November, Leicestershire]


13 Responses to “What makes a house an eco-house (in Britain)?”

  1. eNVie Says:

    I think if your goal is to create a large database of ecological houses, it would be perfectly acceptable to use the rule that only one of the listed criteria be used in order to make it ‘ecological’. That way, more varieties of houses could be included in the database, and more knowledge could be spread. However, it would be interesting to also include a rating system of some kind to compare which houses are more ecological than others, to deal with the problems you described (i.e. photovoltaics on a poorly insulated house). I personally wouldn’t call a house ‘ecological’ if it only had one of the criteria on your list, it would have to use several, in both how it is built and the materials it uses (and where they came from). I would instead refer to the database as a collection of houses with ecological aspects.

    • naturalbuild Says:

      Thank you, really useful feedback. We have decided to include a list of eco-features which can be selected for each house – that way a user will be able to search for houses which have, say, 4 or more eco-features. I hope that this will enable people to either look at a broad range of ‘eco’ houses or to search for high performance ‘eco’ houses. As houses improve overall then we could then further refine what we include in the database. Thanks again, Jenny

  2. dave allaire Says:

    Energy efficient windows and good insulation (especially in the roof) are a great place to start. A geothermal heating and cooing system would be a bonus too if the price is right.

  3. By Adopting the above mentioned suggestions we definitely turn an house into an eco – house.

  4. KTB Says:

    Hi Jenny,

    That’s brilliant that you have started the database and your requirement of one criteria for inclusion seems good to me: that one element may be useful or interesting in itself even if the house as a whole may not be considered ecological.

    The issue of criteria and coding is interesting and fraught with problems. I am quite interested in coming in from the other angle and looking at elements which could reduce excess winter deaths, for example, or excess summer deaths or childhood asthma or fuel poverty.

    I would not consider a house to be an “eco-house” because it met one of the criteria on your list but I think it is a fine thing to make the database inclusive by only setting one criteria.

  5. Paul C Says:

    This is an extremely good idea, and keeping the criteria as broad as possible is extremely necessary to avoid a) getting bogged down in endless discussion, or b) developing yet another list. Having said that, there is a danger in single-criterion entry to the database, which is that a project which is clearly not environmentally-friendly in toto might qualify for inclusion on the basis of a single feature (or even a combination of features).

    Given that green building remains a niche, the primary criterion that distinguishes an eco-house from other houses is surely intent (although one can argue whether that intent has been successfully achieved in any given case). Without intent, few of the features listed above would even be considered, since they are either more expensive or less accessible for most developers.

    As green building comes closer to the mainstream, and as planning laws change, the role of intent will obviously become less clear. I do think you should keep the database as wide as possible, but I do think you’ll run into this problem sooner or later…

  6. An interesting list, as mentioned it is very hard to create such a category without endless discussion. It is interesting to see that something such as a house has so many variables in these areas compared to cars, which are primarily judged on their co2 emissions and mileage and which information is brazenly used in advertising.

  7. offgridboy Says:

    Hi Jenny

    Interesting mission (and quite a tricky one)
    It’s you that sets the standards but personally i don’t consider a house to be “eco” if is a high tech one. Maybe it’s very energy efficient, maybe it’s a “passivehaus” but if it’s been built using energy intensive or highly manufactured materials (fancy insulations, blocks, laminated timbers, panels made in Germany and lorried all the way here, and the like) i think it completely defeats the object. If you do, you are supporting the type of industry and the kind of mentality that is made almost everyone believe that building a house with only human power and with simple, non processed materials it’s just a thing for crazy hippies and it doesn’t really work.
    So my suggestion is, less “energy efficiency” and more self built, small scale, simple and honest buildings built with simple and honest materials by simple and honest people.
    Hope this rant hasn’t bored you to death,

    All the best and thanks for your great blog

    • naturalbuild Says:

      Hi, thank you for this. I agree with you in many ways. I feel like I want to advocate very much for the small-scale, self-build using local natural materials – for low impact development basically. I have been trying to illustrate how well these simple approaches work and I agree that developing a database which accepts a more technological focus potentially dilutes all this effort. That said I am keen to make eco-building an inclusive and appealing method. It might be that in including these more corporate approaches I still pigeon-hole the more radical low impact developments. I take your point and I think as the database develops I will have to look at a way of more clearly distinguishing between the approaches. We have populated the database now and the next stage is getting a good front-end designed in order to make it live online. We can then tweek further. Thanks again for your input. Jenny

  8. offgridboy Says:

    Hi and thanks for your prompt reply.
    Sounds like we definitely agree in most things. Just thought after reading your answer that a good idea could be to divide the archive into several (maybe as little as two or as many as four or five) different categories depending on the type of building listed. I don’t know, maybe self built, techno-eco, totally mainstream built by big contractor, low impact…that sort of thing and listing inputs needed, price, impact in the surroundings, “environmental impact” or who knows what other criteria, and that way people could compare and get a better idea of how little for how much you get (other than status) if you decide to go for the conventional approach and how liberating and empowering the self built route can be. I’ve lived in that sort of homes for years and i wouldn’t get back to a “normal” one for all the money in the world.

    On the other hand you’ve maybe thought about this way of organizing things already. If that’s the case, please take no notice of all this. At the end of the day i’m just a carpenter and i guess also a bit of a hippie so…

    All the best and good luck. I’ll follow your blog with interest.

  9. It sounds good construction with green building concept. It is more beneficial to human being that building protects their health, reduce waste and pollution.

  10. It’s so true that installing quality, energy-efficient windows are necessary for building an eco-friendly home. Thermally broken windows, where two sections of exterior and interior aluminum extrusions are connected with a composite strip, are a good choice for green building. And extruded aluminum is highly recyclable, which makes it an excellent material for a sustainable, eco-friendly home. Thanks for the post!

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