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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.

PLEASE NOTE: A download link for Volume 1 will be sent to you by email and Volume 2 will be sent to you by post as a book.

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  1.  
    I am embarking on a whole-house renovation of period property so you would think I could definitely find plenty of uses for the Green Homes Grant? So far my list of options is basically bare. Somewhat frustrating. Having come to various dead ends on the insulation I started looking into GSHP but it turns out that you lose 5K from your RHI payments so the GHG is basically worth nothing.

    Here's where I'm at on the primary measures:

    Insulation:
    Solid wall - yes but I can't find anyone who will install internal.
    Cavity wall - NA
    Under-floor insulation (solid floor; suspended floor) - yes but again can't find anyone to do it. One company said due to low demand they are not Trustmarked for this.
    Loft - NA; having loft conversion.
    Flat roof - NA
    Room in roof - NA
    Park home insulation - NA

    Low carbon heat (where the home is suitably insulated):
    Air source heat pump - no outside space
    Ground source heat pump - now considering but one company won't provide quote for GHG work as over-subscribed.
    Solar thermal - possibly; not looked into this yet and not sure how worthwhile this would be.
    Biomass pellet boilers - No
    •  
      CommentAuthordjh
    • CommentTimeOct 2nd 2020
     
    Posted By: modernvictorianRoom in roof - NA

    Sorry, haven't checked but why is this not applicable, given "having loft conversion"?
    •  
      CommentAuthorfostertom
    • CommentTimeOct 2nd 2020
     
    Just got round to reading up about the grant.

    Strikes me the 3 month deadline, from receiving the voucher to satisfactory completion of works and redemption of the voucher, is a tall order. So much can, and almost always does, delay a start or prolong the works - then you're liable for the costs but grant evaporated.
  2.  
    ''Air source heat pump - no outside space
    Ground source heat pump - now considering but one company won't provide quote for GHG work as over-subscribed.''

    Slightly confused....

    Would the GSHP trench-field/bore-holes be a long way from the house? If not, why can you not sit your ASHP where the bore-holes would be and use insulated heat-main for the flow and return?

    I also echo djh's confusion re room-in-roof, but is it that you have already contracted for the room-in-the-roof with a co. which would not 'roll the grant in'?
  3.  
    Nick, the GSHP would be about 6m from the house. And that is pretty much where the garden ends. I did look into ASHP but felt that the noise would annoy the neighbours too much (I'm in a victorian semi so the gardens are long a and thin - not mine though as I have a garage at the end of it).

    The room-in-roof I will look into again. I assumed this was for insulating an existing room which was poorly insulated when installed. Not a new loft conversion which would have to be constructed to minimum Building Regs in any case. But will check again.
    • CommentAuthorjfb
    • CommentTimeOct 5th 2020
     
    Are you talking about a GSHP with borehole rather than a flat array?
    I imagine the upfront costs of a GSHP are much more than an ASHP.

    What heats water/heating at the moment? Is it on mains gas? Radiators?

    If going heat pump route you really would need to improve insulation and radiators would need to be larger than they are now (to keep flow temperature down). UFH might be an option if you can insulate the floor well.

    Noise could well be an issue for an ASHP. Noise can also be an issue for a GSHP as the compressor is normally housed inside somewhere so could be a real problem for your own comfort.
  4.  
    I am completely refurbing the house, taking out the radiators and replacing with UFH throughout, as well as replacing all windows, insulating and installing MVHR. I was hoping to ditch the gas boiler and replace with a heat pump but I can't find an option that fits the house (and the budget). Yes I was thinking about a borehole GSHP. I don't have a utility room so housing a large compressor could be an issue.

    Looks like it is back to the drawing board in terms of how I spend this wonderful gift from the government!
    • CommentAuthorrevor
    • CommentTimeOct 6th 2020
     
    Somewhere in the Manchester area a pair of Victorian semis were developed into passive houses very successfully I understand. Might be worth trying to find out what they did might be some really good ideas there.
    The success or not for you would be to take a fabric first approach. That is Insulation, elimination of draughts and avoidance of cold bridging. I can imagine there will be plenty of scope in a Victorian house just on these items alone I know used to have one. Because of my location I was also able to make considerable use of solar gain which has also helped to be as green as I can.
    I would consider thermal solar if you can I did one, installed myself and coupled to a thermal store. RHI was available but not for feeding thermal store. Perverse. This summer has been first season in use and have hot water from March to now with hardly any use of boiler. In total about 1hr if that.
    On my current build/refurb coming to an end I considered ASHP GSHP (have 25 acres to have played with) & pellet boiler but because I attended to the fabric first approach the need for sophisticated high maintenance technology was not required because of my low heat requirement so ended up with a gas boiler on bottled LPG.
    At first flush not very green I know but how much non green energy goes into making and running all the renewable systems? My gas cost £400 for the year and a good chunk about 25% went on heating the floors in order to condition them before tiling. Hopefully when got my solar PV in the need to consume gas will be less
    Be careful not to be led by chasing the grants (5K does not go far) the real beneficiaries are the installers. If you can pick up some benefit on the way all well and good.
  5.  
    I'm not going as far as the Manchester Victorian semis although I totally agree they did a great job to get them PH standard. I don't have the budget (or the space) I'm afraid. I will be insulating walls, floors, loft, improving airtightness as far as I can and installing UFH and MVHR. I think the solar thermal would help with the UFH if I had a thermal store (so no RHI payments probably?), although I suspect the gains would be very little in the winter when I would need the space heating the most.
    •  
      CommentAuthordjh
    • CommentTimeOct 7th 2020
     
    Posted By: modernvictorianI think the solar thermal would help with the UFH if I had a thermal store (so no RHI payments probably?), although I suspect the gains would be very little in the winter when I would need the space heating the most.

    I think the latter rather than the former. Disregard solar power, either thermal or PV, as regards winter space heating, IMHO. Solar gains through windows are important at any time of year in a well-insulated house, but solar power devices not so much. Maybe a bit of hot water - DHW rather than space heating.
    • CommentAuthorCWatters
    • CommentTimeOct 10th 2020
     
    I am embarking on a whole-house renovation of period property


    Just checking you know about the VAT you can save if its been empty more than 2 years or 10 years?
  6.  
    Thanks but it hasn't unfortunately!
  7.  
    So thinking about solar thermal, given I will be installing UFH throughout would it make sense to install a thermal store rather than an unvented cylinder?
    • CommentAuthorjamesingram
    • CommentTimeOct 10th 2020 edited
     
    yes, might be worth looking into as ST will just add to this when it can. whats your main heat source going to be?
    ST gives you better output per m2 than PV , but PV with an immersion dump could do similar but is more versitle than ST and much less complex.
    I been thinking more about all electric house supplies more recently.
    With the falling CO2 intensity of grid electricity and these new variable tariffs that take advantage of cheap night or off peak energy without the additonal standing charge of E7, linked with PV and some thermal store or heat battery.

    Things have changed quite a bit in the last decade. Gas CO2kgkW no longer always beats Electric hands down and with thermal storage peak Electric CO2kgkW at high demand time is no longer as a concern as it was as stores can be charged at low
    CO2 times ( night nuclear) and or importantly low cost times with less complications.
    I think its worth a new investigation as to how they compare, environmentally and cost wise as means of primary energy source.

    https://tepeo.com/technology

    this has just come to my attention. I'm not sure of details but its likely to be a heat battery along the lines of
    the SUNAMP kit. Im slightly suspicious if it'll hold enough or function as required but with the future greener grid such tech if priced right could be a simplier solution than a plumbed wet thermal store.

    more info on the SUNAMP kit and similar thinking here from a GBF contributor and all round low carbon home hero :bigsmile:

    http://www.earth.org.uk/note-on-solar-DHW-for-16WW-UniQ-and-PV-diversion.html#Ahoy2
    • CommentAuthorEd Davies
    • CommentTimeOct 10th 2020
     
    DJH, why do you think windows are more efficient/effective than other solar-power devices? Also, why DHW rather than space heating which is usually at lower temperature?
    •  
      CommentAuthordjh
    • CommentTimeOct 10th 2020 edited
     
    Posted By: Ed DaviesDJH, why do you think windows are more efficient/effective than other solar-power devices?

    Mostly just experience. Sun through windows seem to make much more difference to internal temperature whilst it doesn't seem to generate much extra power in winter.

    Also, why DHW rather than space heating which is usually at lower temperature?

    Because DHW is required at all times including especially when there's lots of sun. Space heating is required at times when there isn't any sun.
    • CommentAuthorEd Davies
    • CommentTimeOct 10th 2020
     
    Posted By: djhMostly just experience. Sun through windows seem to make much more difference to internal temperature whilst it doesn't seem to generate much extra power in winter.
    Is that because the solar collectors you have in mind are angled for summer collection (i.e, at a shallow angle)? Ideally in winter they should be near vertical (like most windows).

    Because DHW is required at all times including especially when there's lots of sun. Space heating is required at times when there isn't any sun.
    Fair enough, I was reading your comment in the context of winter operation.
    •  
      CommentAuthordjh
    • CommentTimeOct 10th 2020
     
    Posted By: Ed DaviesIs that because the solar collectors you have in mind are angled for summer collection (i.e, at a shallow angle)? Ideally in winter they should be near vertical (like most windows).

    I don't know. They are at a fairly shallow angle - they're constrained by the roof. I agree that more vertical panels would be effective in winter. Sadly simplicity is also a constraint - even single axis tracking is not feasible/permitted, let alone two-axis.
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