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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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    • CommentAuthorSimon Still
    • CommentTimeSep 8th 2021 edited
    Some friends are just in the process of buying an early 60's Barratt built end of terrace townhouse. Flat roof, lots of glazing (originals replaced with double glazing about 10 years ago) but pretty much original otherwise.

    Heating is electric - some ancient wall electric bar things and some original electric underfloor (and immersion heater driven water in a big newish stainless steel tank with a load of unused heat inputs).

    they want to
    - improve the insulation and airtightness.
    - make it warm (so a modern heating system)

    It has a gas connection (currently used only for the cooker), the cavity walls are thought to have been retrofilled. and apparently the estate rules don't allow either solar panels or air source heat pumps.

    Those restrictions are an interesting challenge and I'm wondering how they can be sustained so they're unsure what their priorities should be. Infra red electric panels have been mentioned (but I know nothing about them and don't see how they really work at scale as room heating)

    Thoughts and suggestions?
    • CommentAuthorrevor
    • CommentTimeSep 8th 2021
    Posted By: Simon StillIt has a gas connection (currently used only for the cooker), the cavity walls are thought to have been retrofilled. and apparently the estate rules don't allow either solar panels or air source heat pumps.

    If it was me I would not entertain a house in this day and age with these particular restrictions but if going through with this think that gas heating is the best option, electric without it being via a heat pump is going to be prohibitively expensive to run. If cavity filled not much option there and EWI being on a terraced building may not be possible. Having more info on the cavity insulation would be useful to see what the u value works out you will need this to see what the heating requirement of the house is. So loft insulation increase yes. A spec of the HW tank would be a good start size what the input /outputs are, may have useful coils e.g wood burner. Don't really know about IR heaters not worked with them. Leave that it others to comment. Is there an EPC done on the house any ideas from that not that they are that useful?
    From what I've seen I think there is scope for internal insulation without negatively impacting on room sizes. Since a flat roof I don't think there is a loft as such, but again, could insulate that ceiling internally.

    It's got loads of character and fantastic views and location, but does have some challenges in terms of updating!

    A load of original parquet flooring as well to complicate any ideas about wet underfloor systems.

    I'd thought the obvious answer was solar and heat pump mounted on the flat roof (which wouldn't have been visible from ground level or other properties due to the position but has only become evident that's not permitted just before exchange....

    The easy, obvious, answer that's cheapest right now is a gas combi boiler but it shouldn't be.
    • CommentAuthorEd Davies
    • CommentTimeSep 8th 2021
    is there any option for use of variable tariffs to reduce the cost of direct electric? Obviously, the big tank is good news from this point of view. How much heat can be stored in the floor?
    • CommentTimeSep 8th 2021
    If the heaters and the UFH is original then chances are that all the wiring is original too. So it will need to be completely rewired. Plumbing and gas connections will also need checking.

    Like revor, I wouldn't buy this house, regardless of how attractive it appears.

    If proceeding then I wouldn't assume EWI is not possible. It should give better results than IWI so push hard to do that. Also push hard to overcome the restrictions on solar panels and heat pumps. Who would enforce them would be my first question? And why, what is their motivation? Plus of course, are the restrictions valid and enforceable in the first place?

    It sounds like like it'll be a major renovation, but as long as they're comfortable with that and have the money then they should sit back and make a plan; don't rush.
    • CommentAuthorMike1
    • CommentTimeSep 9th 2021 edited
    Posted By: Simon Stillapparently the estate rules don't allow either solar panels or air source heat pumps.
    If it was built in the 60's those wouldn't be original restrictions (nobody envisaged having them). What do the rules actually say / who updated them? And is everyone obeying them (I once lived on a 60's development that had covenants requiring all the front gardens to be open plan - in practice they all had walls, fences or hedges).

    Other possibilities:
    - replace some of those windows with PV glazing (e.g. polysolar.co.uk)
    - replace garage door with grill & put ASHP behind it;
    - borehole + GSHP in garage (but not cheap);
    • CommentAuthordereke
    • CommentTimeSep 9th 2021
    I have a house in a conservation area.
    One of the restrictions is that every house must maintain their hedge at the front of the property.
    My house is one of the few that still has a hedge. No one cares.

    It would be interesting to hear more about these heat pump restrictions. I'd be tempted to install one anyway. That covenant is not compatible with the governments climate goals so surely would be easily challenged in court - not ideal but someone has to do it!
    They will be spending 100s of £1000s to buy the place and so 10s of £1000s on mortgage payments (or lost opportunity costs of their capital). In that context, plus-or-minus a few £1000s on heating will make little difference either way to their decision, the main thing is they like the house and its location.

    Thats why most homebuyers are unfussed about energy performance :-( but it sounds like your friends are keen to improve it :-) so better that they take it on than someone else does. They can easily knock many kWh off an older house, much harder to shave that much off even a mass-market new build.

    They need to decide (as we all do) how much time/money they are prepared to sink into energy emissions reductions
    and comfort improvements which might not payback financially and get their objectives clear, this is difficult.

    Terrace housing is a pretty efficient shape so it should be possible to get the heat usage well down. Perhaps focus on reducing heat losses, rather than reducing cost of providing the heat?

    Could they replace the flat roof covering with a "warm roof" perhaps 2-300mm higher (=insulation boards on top of extg roof deck, new membrane over the top)

    Then EWI or IWI - there's a lot to be said for IWI on existing CW as it avoids the EWI problems with cold bridges at the roof and ground level junctions, and with air movement in a cavity of unknown filled-ness and behind internal wall linings (maybe wet plaster in 60s). Address airtightness at the same time.

    Probably not worth touching doors windows if relatively recent.

    Floor is an issue - uninsulated parquet floor is cold underfoot and uninsulated ufh is wasteful. Keep some and replace the rest, espc round external walls.

    Given there's no wet CH system, it would be expensive/disruptive to install gas or A-W heatpumps.

    Go electric for remaining heat if at all possible, much lower emissions than gas over the foreseeable lifetime. Look at storage heaters on a time-of-use tariff. IR and other panel heaters are also cheap to buy but you are stuck with peaktime electricity prices (and intensity).

    Don't forget ventilation (heat recovery) and cooking (get induction, lose the gas standing charge). Is there somewhere to park/charge an EV?

    If they are in England, the ill fated Green Home Grant scheme was replaced by a system where local councils dish out £10k grants, for households earning less than £30k.

    Don't bother with retrofit PV on flat roof, the time for that has passed. If keen, put the money into a large scale solar farm or wind farm project instead.
    <blockquote><cite>Posted By: WillInAberdeen</cite> the main thing is they like the house and its location.

    ... so better that they take it on than someone else does. They can easily knock many kWh off an older house, much harder to shave that much off even a mass-market new build.

    exactly. Some good suggestions there Will.

    It's over 4 floors and the 'lower ground' (on one side/ground on the other) has a garage/utility room -larder and a 'craft room' (which is what estate agents call rooms that aren't living/dining/kitchen/bedroom.
    I'd wondered about insulating the ceiling of the basement and treating that floor as being outside the heated envelope (or at least, climate controlled to control moisture but not heated to the same temp as rest of house). That might help the uninsulated floor of the kitchen/living/dining rooms.

    I had same thoughts on IWI and roof too. Good to hear someone else thinks that might be viable. And I'd thought air-to-air heat pump would be best solution but the restrictions on external boxes (don't know full details) a problem. Idea of hiding it with the garage is interesting.

    None of the properties on the estate appear to have solar or visible heat pumps (definitely nothing on roofs) so I'm thinking the rules are applied BUT I do wonder how long they can maintain that for.
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