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  1.  
    Greeting from Edinburgh! I've just joined the forum (although I've been reading and following for some time now!) as I'm in the early stages of planning a new self build project.

    As I've continued to research I've just ended with a big headache with all the pros and cons of various options!

    The plot is rural, and serviced (no gas). We are currently in the planning stages, with plans currently being drawn up. It is expected to be 1.5 story, 250-300m2 south facing. We're looking at a 'U' shaped floor plan, with 2 glazed gable ends to the rear (south)... which I know is a suboptimal layout.

    The current line of thought is to place more emphasis on the fabric of the building, lending the methods from PH. I'm not dead set on achieving PH, but not ruling it out as such. We have a healthy but limited budget, so it's important that we balance capital cost with ROI.

    So, after all that preamble, my question is what is the optimum configuration for Heating, HW and Elec?

    I'm tempted to go down the route of having no additional heating, but nervous of this approach. At the opposite end of the spectrum, I'm also nervous of overheating in summer months due to the south facing glazing.

    So what I'm currently considering is having UFH - is it possible to use this to heat in winter, and cool in summer?

    An alternative to UFH is to just have some form of supplementary elec heating. I did start looking at some economic infrared heaters from Herschel.

    If we do go down the UFH route as a delivery method, the next question is how do we supply the heat...?

    Started looking at PV-T, after speaking with Seamus at Viking House. I have some reservations about winter performance for warming the water?

    Then I also started investigating a ASHP. Perhaps on it's own, and rely on the grid. Or supplemented with PV?

    Or perhaps even a combination of PV+T & ASHP, which may be over kill!

    Sorry for the life story... but I'd love to hear some thoughts.

    Thanks
    Anthony
    • CommentAuthortony
    • CommentTimeApr 7th 2017
     
    Design fabric first with one of his slabs, no need for heating in a new build if you insulate and do air sealing, 3g windows. You are right about water heating. PV is a good idea and so is ASHP, ground source is worth considering and water source is even better. Air tight with ventilation system would be a good plan and low target u-values.

    Hope it all goes well, think about a lot before you decide what to do.
    • CommentAuthorDarylP
    • CommentTimeApr 7th 2017
     
    How about this...
    aim for envelope U-values 0.1W/m2k
    windows/doors 1.0W/m2k with max. solar gain (open the windows in summer?)
    forget CH as such
    allow for electric panel heaters but do not install
    PV for DHW, backed up with E7 -/+ WBS for those cosy winter nights?
    MVHR and PH-levels of air-tightness

    No amount of insulation will give you DHW, but give you many times ROI in space heating costs.
    Good luck:smile:
    • CommentAuthorMarkyP
    • CommentTimeApr 7th 2017 edited
     
    good luck with you plans, it can feel overwhelming at times, so much to consider. Keep it simple and focus on the basics first. I would agree with Tony, new build should not need heating - there are plenty of people here who have built without heating. And that will save you a lot of money - planning out the need for a wet UFH system in a large house, plus heat source will save you £1000s.

    For now I would concentrate on figuring out the build method for your sub-floor, walls, roof. Each of these can achieve exceptionally good u-values in a new build situation, often for a modest incremental cost over a standard building regs u-value if you choose the right insulation. It's relatively cheap to add thicknesses of EPS and mineral wool, for example. And in new build you can easily allow for the necessary thicknesses of these good value materials.
  2.  
    Thanks for the replies - makes me feel at ease!

    @DarylP, when you say PV for DHW, do you mean use the Elec generated from PV to power an Immersion?

    @MarkyP - I'm currently exploring a passive slab for the sub-floor. For walls and roof, going TF/SIPS. Something like that from VH. I've also been looking at Scotframes Val U Therm. I did look at other TF options, which involved another envelope of rigid insulation internally behind the service void (not sure I'm keen on that).
    • CommentAuthorgravelld
    • CommentTimeApr 7th 2017
     
    The other thing about heating is to consider resale of course. People don't know about this stuff, so showing them a house without a heating system may raise some eyebrows.

    It might also persuade an EA this is an "eco home" which you DON'T want them to think. You have (will have) a high performance home which is comfortable, warm and healthy.
    • CommentAuthorDarylP
    • CommentTimeApr 7th 2017
     
    @anth.payne
    Yes PV - photovoltaic panels ; electricity for resale, PowerWall, or to heat your DHW.
    If you ever think of selling, you will limit your potential market to 'switched - on' types.
    Remember this forum is self-selecting, so most 'general populus' people will baulk at buying a house with no CH!:confused:
    • CommentAuthorGotanewlife
    • CommentTimeApr 7th 2017 edited
     
    Posted By: DarylPIf you ever think of selling, you will limit your potential market to 'switched - on' types.
    +1. Having an easy to retrofit heating option such as pipes to where radiators 'could' be fitted and a space where a gas boiler fed from a tank in the garden 'could' be fitted will cost very little, just some pipes in the house and a pipe to a nominal outside space for a tank and of course an inside space currently filled with shelves and or the ironing board and ladder.

    As for actual heating since you will obviously need MVHR (assuming you use a ducted system) why not just put in a post heater and design for 95-98% of conditions, then if the sums don't quite reflect your understanding of "It feels so cosy at 19 deg with a jumper when there are no draughts and all the mass is radiating 19 deg." then you have a simple and cost effective back up.
    • CommentAuthorEd Davies
    • CommentTimeApr 7th 2017
     
    Guessing that the OP intends to stay in the house for a while resale might becomes less of a problem as people start to have different expectations, at least for relatively recent houses.
    • CommentAuthorGotanewlife
    • CommentTimeApr 7th 2017 edited
     
    For sure, but how much does 4/6 pairs of rad pipes plus one to outside cost?

    And one person's cosy in a jumper is another person's cold in a single layer or for gran or for the 2 babies.
    •  
      CommentAuthordjh
    • CommentTimeApr 7th 2017
     
    I don't believe it is sensible to build a house with no provision for heating. I built a house to PH standard (it's certified) and without heating at the time of completion but I did make provision for and fitted a post heater shortly after completion. We also use some portable radiant heaters, so we can concentrate all the heating into the overnight E7 period, and we have PV so DHW is provided by that most of the year.

    I'd like to see the "plenty of people here who have built without heating" come forward and confirm that they have built a house with no heating and that they don't use any heating. If anybody is willing to do that, then I'd be very interested to see the location, plans and PHPP of the dwelling.

    You shouldn't really need to consider active cooling for a new-build south-facing house near Edinburgh. Part of the design task is to eliminate that need as well as reduce the winter heating demand. Having said that, it is possible to use heat pumps to do both heating and cooling and UFH loops are one way to distribute that. Air flow is another way, but there are limits to that unless you install a ducted heating system as well as a ventilation system.

    You need to decide whether to install a heat pump. That can provide space heating and space cooling and hot water and all in an energy efficient way. The downside is the capital cost and maintenance of the system. I think the simplest alternative is what I have - pure resistance heating and PV to power it most of the time. It's difficult for me to justify installing a heat pump just to reduce my electricity usage for four months of the year.

    300 m² is a big house. PHPP would like to see 8 or 9 people living in that size of house. The easiest way to stretch your budget might well be to consider a smaller house unless you really need the area.

    I think talk of estate agents or people at large being scared of eco houses is misplaced. Certainly we haven't found that. Most people will be convinced by the bills, and by visiting the house.
    • CommentAuthorDarylP
    • CommentTimeApr 7th 2017
     
    @djh
    We designed and built a house without central heating.
    It does, however, have two 2kW Tesco fan heaters which are used for may be 10mins a day, for perhaps 3 weeks each year?
    People, cooking, washing, solar gain, MVHR, ironing = enough heating.
    £'000s saved on infrastructure and install costs for a CH boiler/system.
  3.  
    Posted By: anth.payneWe're looking at a 'U' shaped floor plan, with 2 glazed gable ends to the rear (south)... which I know is a suboptimal layout.

    Are you wedded to this layout?
    You are right to be considering PV, but this performs best on a south facing roof, however your south facing roof is limited and perhaps shaded a bit by the 2 south facing gable ends. How much roof space do you have on the south facing inside part of the U shape? Otherwise would you need a split system part east facing part west facing with an appropriate controller to manage this - can be done but messy and considering you are starting from scratch plan in the optimum use of the PV
    • CommentAuthorsnyggapa
    • CommentTimeApr 7th 2017
     
    >allow for electric panel heaters but do not install

    we did this - low cost and effective, just run a bunch of 4mm radials to a blanking plate in every room.

    We ended up with heaters attached to three of them (dining room and the 2 bedrooms) but our house is not as well specced as yours due to constraints of it being a retrofit. They are programmed to come on for an hour or so each morning and 2 at night but the thermostats on them keep the usage to minimal, especially over this warm winter - but we have single blanking plates at strategic points if we needed more heat.

    Domestic hot water is simple water tank on an economy 7 timer, cheap to install and maintain and not awful to run. If I had a bigger roof I would get more PV and use an immersum or similar to heat the hot water from the PV but the roof we have is not big enough to warrant the bother

    Don't underestimate the value of keeping things simple. An all electric heating and hot water system can be installed for very little money and repaired for little.

    (I would also consider an air to air heat pump if I had an open plan building)

    -Steve
    • CommentAuthorMarkyP
    • CommentTimeApr 7th 2017 edited
     
    I think running heating pipework for the possibility that a prospective future buyer might otherwise be lost is going too far. Quality, high performance self built homes are not run of the mill, and wont attract run of the mill buyers so why cater to them? Whether you agree with them or not, a wood burner is currently the fashionable lifestyle heat source of choice , IF you felt the need to cater to buyer's whim, then that's what I'd put in. And then you have the issue of overheating - I might consider a low output WBS in a large, open plan space with plenty of head room. But in a house at or close to PH in a small room I suspect it will quickly get uncomfortably warm.

    I could have been clearer earlier - In "plenty of people here have built without heating", I meant they didnt build in a conventional heating system. I dont have numbers of such people, but reading here formed the view that lots have managed fine without conventional heating and maybe ad hoc supplementary heating. Point really was that a full blown wet UFH plus heat source for a 300m2 house seemed like a lot of money for something that might rarely or never be needed. Maybe the OP might consider some elec rads, or even just some portable heaters. But I woundnt be worrying over plans for piped wet systems of any kind if I were in the position of new build.
    • CommentAuthortony
    • CommentTimeApr 7th 2017
     
    I like living without having heating bills to pay or heeding to worry about service and repairs etc.
  4.  
    Thanks - lot's of useful comments there.

    I take the point about future resale, but I plan for this to be a home for life. IF we do sell, then it should be way in the future, when PH/Low energy homes will be more common place (or so you should expect).

    Perhaps my original plan for just elec panels is going to suffice... we both prefer a more temperate climate anyway. I've never measured my current room temps, but I rarely set my thermostat above 18, and that's in a very drafty house!

    In terms of the point about the layout - yes it will impede available roof space for PV, but there should still be ample space up there for a huge array... once we get plans through, we may have a better idea on available space.

    Depending on cost, I may still get UFH pipes laid, but not actually connect them up to anything. That way it's future proof.

    I think the theme here is that I'm probably over thinking the need for space heating... simple is better, and at the end of the day, it's only going to be required for a couple months of the year. The main living space will be open plan, so a WBS may work there, but I'm not bought into having a stove tbh.
  5.  
    Having remembered that I have a digital thermostat in the cupboard, I thought I'd do some testing.

    My flat is located on the Firth of the Forth, and faces North East. It has an open plan living/dining/kitchen with lots of glazing (which is drafty).

    Today its 12C outside, and the indoor temp is 19.4C, which for me is 'T-shirt Temp' and comfortable despite the drafts.

    So I think that suggests I'm over thinking the heating!
    • CommentAuthorSigaldry
    • CommentTimeApr 7th 2017
     
    For me, I'd go for a really good fabric (with good junction detailing), low air permeability, with a good MVHR unit with summer bypass. ASHP (for occasional heating and for hot water), with a good cylinder and PV southerly facing to help reduce the overall electrical demand.

    For summer overheating, solar shading from Brise-soleils above any larger feature windows to limit solar gains in the summer and I'd ensure the design accommodated night-time purge ventilation for the summer months.
    •  
      CommentAuthordjh
    • CommentTimeApr 7th 2017
     
    Posted By: anth.payneMy flat is located on the Firth of the Forth, and faces North East. It has an open plan living/dining/kitchen with lots of glazing (which is drafty).

    Today its 12C outside, and the indoor temp is 19.4C

    Flats can be quite a lot easier to heat than a detached house, because walls with neighbours are warm, as are floors and ceilings. So it depends as much on how the building is laid out as on the aspect for flats.
    • CommentAuthorCerisy
    • CommentTimeApr 7th 2017
     
    We have a self-build here in Normandy, built to PH standards and we have no central heating - well - okay, we do have a small wood burning stove that uses the wood from our land and do use it over the winter on cold days. As there are only the two of us (so not a family and their activities adding to the heating!) and I, regretfully, designed the house as mainly open plan including the staircase, which means that the heat from the stove goes upstairs rather too quickly, ours isn't an ideal example. But we certainly don't regret leaving out the CH.

    My main concern would be with solar gain. We have been in our house for nearly two years and have only used a summer duvet. When the house gets warm it sure holds the heat. With large south facing windows you will have a serious problem in the summer - can you include some form of solar shading for the height of the summer sun?
    •  
      CommentAuthordjh
    • CommentTimeApr 7th 2017
     
    Posted By: anth.payneWe are currently in the planning stages, with plans currently being drawn up.

    Another important point, BTW, is to get a full PHPP model and confirm that it works alright for heating and overheating before you apply for planning permission. Changing window sizes or moving them and adding extra features like brise soleil might require resubmitting planning, which most people would rather avoid.
    •  
      CommentAuthordjh
    • CommentTimeApr 7th 2017
     
    Posted By: DarylP@djh
    We designed and built a house without central heating.
    It does, however, have two 2kW Tesco fan heaters which are used for may be 10mins a day, for perhaps 3 weeks each year?
    People, cooking, washing, solar gain, MVHR, ironing = enough heating.

    Your total heating demand is 2 x 2 x 21 / 6 = 14 kWh per year? That's an astoundingly low demand. Way, way better than my house. What would be the demand at PHPP standard conditions? Are you prepared to share your details, maybe in a separate thread?

    I don't have a problem with designing houses without central heating, but designing them with no heating at all is foolish, IMHO, and I also think it is wise to have a backup plan in case the house doesn't meet its design specifications.
    • CommentAuthorDarylP
    • CommentTimeApr 7th 2017
     
    @djh,
    We did think about PHPP / PH, but as it is my 'day job', and I am not PH trained yet, we couldn't, so we went overkill on the thermal envelope performance, thermal bridging, air-tightness and 3G glazing.

    Uvalues are not available now, archived, but around .09W/m2k across the board IIRC,
    + 0.9W/m2k glazing, all 3G, all but one opening South / South West facing
    Practically zero thermal bridges / Htb, through continuous 200mm EPS/PIR around the envelope.
    All internal OSB joints glued/sealed, all outer insulation joints taped/sealed.
    ATT result circa .9m3/m2h or thereabouts.
    We put in internal / external temp monitors for the first 365 days, internal temp never dropped below 16 deg,
    but the occupants felt this too low, hence the fan heaters.
    LPG DHW costs about £110 pa, no PV or solar DHW, yet?
    So I think entire running costs worked out at just over £1.45 per day all inc. for that year.
    Cheers
    :smile:
    • CommentAuthorgravelld
    • CommentTimeApr 7th 2017
     
    Posted By: djh
    I don't have a problem with designing houses without central heating, but designing them with no heating at all is foolish, IMHO, and I also think it is wise to have a backup plan in case the house doesn't meet its design specifications.
    but at this level, and ignoring concerns about resale, the backup can just be plugin heaters from Argos, right? We're talking peak demands in the very low single figures kW, and that's OK the coldest days.

    Very low capex which can buy a lot of electricity.
    •  
      CommentAuthordjh
    • CommentTimeApr 7th 2017
     
    Posted By: gravelldbut at this level, and ignoring concerns about resale, the backup can just be plugin heaters from Argos, right?

    It depends what 'this level' is and what your expectations of a heating system are. But yes, plug in electrical heaters are one of my backup plans. Camping gas stoves are another.
    •  
      CommentAuthordjh
    • CommentTimeApr 7th 2017
     
    Posted By: DarylPUvalues are not available now, archived, but around .09W/m2k across the board IIRC,
    + 0.9W/m2k glazing, all 3G, all but one opening South / South West facing
    Practically zero thermal bridges / Htb, through continuous 200mm EPS/PIR around the envelope.
    All internal OSB joints glued/sealed, all outer insulation joints taped/sealed.
    ATT result circa .9m3/m2h or thereabouts.
    We put in internal / external temp monitors for the first 365 days, internal temp never dropped below 16 deg,
    but the occupants felt this too low, hence the fan heaters.
    LPG DHW costs about £110 pa, no PV or solar DHW, yet?
    So I think entire running costs worked out at just over £1.45 per day all inc. for that year.

    Very good U-values and airtightness, well done. It shows the difficulty of comparing like with like instead of apples with pears. I keep my house at a minimum of 20°C because that's the PHPP minimum so is useful for comparison. The summer bypass came within 0.2°C of opening a couple of days ago; we'll see what happens this weekend.

    BTW, "Comfort cannot be defined absolutely, but the World Health Organization's standard for warmth says 18C (64F) is suitable for healthy people who are appropriately dressed. For those with respiratory problems or allergies, they recommend a minimum of 16C (60.8C); and for the sick, disabled, very old or very young, a minimum of 20C (68F)." according to the BBC.
    •  
      CommentAuthorfostertom
    • CommentTimeApr 7th 2017 edited
     
    But new adaptive comfort theory
    https://www.amazon.co.uk/Standards-Thermal-Comfort-temperature-standards-ebook/dp/B019P2PNCI/ref=sr_1_1?ie=UTF8&qid=1491601240&sr=8-1&keywords=Standards+for+Thermal+Comfort%3A+Indoor+air+temperature+standards+for+...
    and a Sue Roaf article in Green Building mag about 2009
    is much more forgiving about fixed 'comfort temperatures - 'comfort' substantially follows prevailing temp - tolerates much hotter in summer, requires warmer in summer.
    •  
      CommentAuthordjh
    • CommentTimeApr 7th 2017
     
    I don't have much respect for Ms Roaf's thinking I'm afraid. But I doubt they're recommending lowering minimum temperatures; from what I remember it was mainly about being flexible on maximum temperatures, with which I have no quarrel.
    •  
      CommentAuthorSteamyTea
    • CommentTimeApr 8th 2017 edited
     
    I know someone that built to passive house standards who has found that using a single circuit UFH system is useful for redistributing solar gain around the house (imagine a sun heated hotspot). He just pumps the water around, no heating or cooling. You can of cause use a heat pumpp for cooling if you rally need to.

    I am a fan of basic DHW, so a simple well-insulated cylinder and E7, though it would be nice to use a heat pump, it really depends on your water usage, if you don't use much, a 200lt cylinder at 50°C will do you. A PV system that cost £4-5k, will currently buy you about 20 years worth of E7 hot water.

    You can get films for windows that can reduce the solar gain, they can be retrofitted if you find there is a problem.

    You have not mentioned ventilation. In an airtight house you will need a good system. Generally a pure mechanical ventilation and heat recovery system is not good enough to 'heat' a house, there is too little mass air flow.
    You may want to explore a larger system that can contribute to space heating. It does depend on your layout and budget.

    Building a house is more arithmatic and basic engineering than science.
   
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