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Green Building Bible, Fourth Edition
Green Building Bible, fourth edition (both books)
These two books are the perfect starting place to help you get to grips with one of the most vitally important aspects of our society - our homes and living environment.

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    • CommentAuthorargy
    • CommentTimeJan 21st 2013
     
    I have my first self build in for planning approval at the moment - a 250 sq m New England style timber framed house - with no particular requirements of the local authority to achieve any CSH level

    My issue is whether to go for a normal gas boiler and some reasonable level of insulation to do the minimum to get through Building Regulations or to try and ramp things up a bit to achieve a higher energy efficiency

    I've looked at MVHR (including linked in air source heat pumps), passive stack ventilation, passive flue gas heat recovery, heat pumps, CHP, pv, solar water, the NHBC report (Energy efficient fixed appliance and building control systems) etc (wind, biomass, water not relevant to us) - but it all seems so expensive for the payback that you get out of it. And that's not including electricity costs, breakdowns, maintenance, ancillaries (filters etc), reduced house value (arguable maybe)

    Everything seems to be based on 10 year returns which when you take in product obsolescence and ancillary costs seems way too long. Are equipment prices being somehow based (managed) on this assumption? For example if income from the government went up and/or electricity prices increased would the capital cost of all the energy equipment also go up to maintain the ten year formula? Or maybe I'm being too cynical. Would there be so many self build magazines around without the advertising revenues of all the energy saving suppliers? (and what impact does this have on their editorial policies?)

    And does the UK really warrant these costs in any event? (we are not Scandinavia or Germany with consistently lower temperatures through the winter)

    I just wonder if, to some extent, the self build community just chasing the law of diminishing returns with all of this?

    Are there proven technologies with fast pay backs (under 5 years) that a novice like myself should be looking at
    - or is it just the case of closing the trickle vents in winter and remembering to switch the lights out!

    Sorry for the element of frustration
    • CommentAuthorSeret
    • CommentTimeJan 21st 2013
     
    In terms of cost effectiveness, insulation gives you the best bang for your buck. It may not be flashy, but it works.
    •  
      CommentAuthorSteamyTea
    • CommentTimeJan 21st 2013 edited
     
    Yes, insulation and associated airtightness every time. You don't see insulation either, or hear it, smell it. It is the unsung hero.

    DHW is my biggest energy use and in my location solar thermal is probably with while, but I would go looking for the cheapest system I could find rather than the most efficient, because, as you say it is a law of diminishing returns.

    Seret has a formula that seem quite sensible:

    £ kgCO2e-1 per year

    Or if I understand it correctly, how much CO2 do I save every year for every improvement £ I spend. This takes into account different fuel types and overall conversion efficiencies.
    • CommentAuthorGaryB
    • CommentTimeJan 22nd 2013
     
    As Seret and ST above, insulation, air tightness and then MVHR.

    You are right about diminishing returns however.

    Once you have the envelope at near PH standard, you can even use electric heating if an E10 tariff; if on the natural gas network a combi boiler or even a balanced flue gas stove can do the job for very little outlay. Off the gas network a small ASHP can just about compete against an oil boiler + tank. Wood stoves are also a cost effective heating option, particularly if the accommodation is open plan or the doors are left open.

    Solar thermal has a longer payback (excluding RHI). I have it myself but I got a 50% grant to install 4 years ago.

    I personally use a 6 year payback for my own house energy improvements. Most have been insulation, draught sealing and electrical power reduction. Our primary heating fuel is oil and over the past 4 years we have reduced oil consumption by 70% and electricity by 47% with no measure having a payback longer than 6.5 years.
    • CommentAuthorRobinB
    • CommentTimeJan 22nd 2013
     
    Have to look at the whole story. A 10 year pay back on something that's going to last 50 is better than a 6 year payback on something that will last only 7 years.
    •  
      CommentAuthorSteamyTea
    • CommentTimeJan 22nd 2013
     
    Not of you move in 5 years :wink:
    • CommentAuthornikhoward
    • CommentTimeJan 23rd 2013
     
    A bit of a mantra on is fundamentals and I am a strong believer in KISS. The 3 best things you can do are a bit like a Tony Blair speech - education education education, but substitute educ with insul. After that airtightness.

    When planning our build 4 years ago, I wanted all the gizmos, but they were the first things to cut to keep on top of the budget.

    Mags are full of ads and features but it is the only way they can make money, but does not reflect what the majority actually do.

    You learn far more from here than you ever will from a mag, I now I have.

    Good luck,

    Nik
    •  
      CommentAuthorSteamyTea
    • CommentTimeJan 23rd 2013
     
    I did an educational piece about insulation for Penwith Transition Town once, out of the ten handouts only 2 were taken.

    There was a lot of self justification going on though because most of the people there thought they were low users of energy, but as usual, none actually knew what they used.

    I gave up on them.
    • CommentAuthorRobinB
    • CommentTimeJan 23rd 2013 edited
     
    Posted By: SteamyTeaNot of you move in 5 years


    I'm hoping the day will come when a higher EPC rating and demonstrably lower bills will be worth something when you come to sell.
    •  
      CommentAuthorSteamyTea
    • CommentTimeJan 23rd 2013
     
    If you want the EPC to effect property values then you have to shock the market unexpectedly, graduated increases just set a new norm and even though though they do reduce usage they do not make much difference.
    Big question is what would the new price of energy have to be to make a difference and create a new paradigm in house building.
    My guess is 50 to 60p/kWh.
    • CommentAuthorjms452
    • CommentTimeJan 23rd 2013
     
    Our big local estate agents are now showing the EPC headline figures on their newspaper advertising. i.e. mention EPC in a 50x50mm Ad (which is mostly photo).

    This seems like a game changer as previously they were at the back of a 4 A4 page brochure, if at all (once you'd already decided you liked a house).
  1.  
    jms452 wrote:
    Our big local estate agents are now showing the EPC headline figures on their newspaper advertising. i.e. mention EPC in a 50x50mm Ad (which is mostly photo).

    Yes, its a legal requirement since 9th January 2013 to display the EPC graph on all paper work relating to the sale or rental of properties. If not enough space is available just the Band can be noted. Listed buildings are exempt from this ruling.
    • CommentAuthorRex
    • CommentTimeJan 23rd 2013
     
    To return to the original question, yes, insulate, insulate, insulate.

    I have a newly built t/f house; been in it 18 months. I looked at all the technology and decided not to put any of it in. The only thing we did include, and I will never see payback, is a 6000 litre rain water collection tank. It's good to know that flushing the toilet is free, if one discounts the initial installation cost!

    Warmcell insulation and 3g are brilliant. I have 300mm in the roof and am the only house in the street that still has a good layer of snow. A newly built neighbouring house, brick built by a 'luxury house building company' has all of 100mm Celotex in the roof and all the snow had melted three days ago.

    So save on technology, spend the money on increasing the insulation thickness and being super, super super diligent on air tightness. Then add MVHR. The two matra that I was advised to follow; Insulate, Insulate, Insulate and Build Tight, Ventilate Right!

    Rex
    • CommentAuthornikhoward
    • CommentTimeJan 24th 2013
     
    Posted By: RexTo return to the original question, yes, insulate, insulate, insulate.

    I have a newly built t/f house; been in it 18 months. I looked at all the technology and decided not to put any of it in. The only thing we did include, and I will never see payback, is a 6000 litre rain water collection tank. It's good to know that flushing the toilet is free, if one discounts the initial installation cost!

    Warmcell insulation and 3g are brilliant. I have 300mm in the roof and am the only house in the street that still has a good layer of snow. A newly built neighbouring house, brick built by a 'luxury house building company' has all of 100mm Celotex in the roof and all the snow had melted three days ago.

    So save on technology, spend the money on increasing the insulation thickness and being super, super super diligent on air tightness. Then add MVHR. The two matra that I was advised to follow; Insulate, Insulate, Insulate and Build Tight, Ventilate Right!

    Rex


    Good post

    I also meant to say about rating water harvesting, but that I still want to do it. I am confident to DIY and with the cost of water in the south west (triple the average) I still feel it is worth it (with pay back in 2-3 years)
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