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Heating and cooling: Heating and hot water for occasionally-used space

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  1.  
    • CommentAuthorNanuchka
    • CommentTimeMay 21st 2021
     
    Hello wise forum!

    Hoping for advice about how to do this in the most environmentally sympathetic way. The space is the top floor of a barn with vaulted ceiling. One big room with entrance hallway/small kitchenette and bathroom at one end. Previously hot water was from an old LPG boiler. Would like to have heating and hot water system this time, avoiding fossil fuel.

    Other considerations are:
    -solar panels and battery storage about to be installed servicing main house and all outbuildings
    -hoping to have a wind generator again at some point (old one installed in 1991 has finally been dismantled :-( )
    -will have small woodburner as plenty of wood available from the land + seasoning/storage space
    -there is space for a hot water tank on the bottom floor of the barn (which is still functionally barn)
    -the space is currently occasional use but may be used full-time at some point
    -the roof and floor are in the process of being insulated and draught-proofed

    Thanks in advance :-)
    • CommentAuthortony
    • CommentTimeMay 21st 2021
     
    Ashp for heating, need to insulate well

    HW point of use might be best option
    • CommentAuthorowlman
    • CommentTimeMay 21st 2021
     
    Keeping things all electric is a definite advantage.
    The WBS, whilst may aesthetically be pleasing, and cost nothing to run except a bit of hard work, may get a bit tedious on the top floor; think logs, ash removal etc..
    Personally I'd avoid any wet system of heating. Hot water could easily be point of use then you only have to think of cold supply.
    Even if you don't do that, keeping the DHW electric via immersion ( resistive load), means you can have direct control from the main dwelling. That goes for CH too, by making that as resistive load/s gives you the same control and also allows you to easily tie it into Solar PV peak production.
    So yes, IMO all electric, and wired back to your main dwelling plant room. It's comparatively cheap to install and extremely controllable.
    At some stage in the future you could also look at an A-A heat pump because one of their advantages is that they happily run alongside and/or complement other CH systems.
    • CommentAuthorphiledge
    • CommentTimeMay 21st 2021
     
    Stop the insulation and draught proofing work whilst you double check youre super insulating and being fully air tight. If youve got a WBS stove youll likely not need any additional heating but I would put electric UFH in the bathroom for comfort. Instantaneous water heater and shower if its intermittently occupied.
    • CommentAuthorNanuchka
    • CommentTimeMay 21st 2021
     
    Thank you all for comments.

    <blockquote><cite>Posted By: owlman</cite>
    Even if you don't do that, keeping the DHW electric via immersion ( resistive load), means you can have direct control from the main dwelling. That goes for CH too, by making that as resistive load/s gives you the same control and also allows you to easily tie it into Solar PV peak production.
    So yes, IMO all electric, and wired back to your main dwelling plant room. It's comparatively cheap to install and extremely controllable.
    </blockquote>

    owlman pardon my ignorance but what is D for in DHW? Does immersion assume tank?
    • CommentAuthorNanuchka
    • CommentTimeMay 21st 2021
     
    <blockquote><cite>Posted By: philedge</cite>Stop the insulation and draught proofing work whilst you double check youre super insulating and being fully air tight. If youve got a WBS stove youll likely not need any additional heating but I would put electric UFH in the bathroom for comfort. Instantaneous water heater and shower if its intermittently occupied.</blockquote>

    We've got 4" PIR going in roof, odd construction makes anything thicker hugely more expensive I think. Floor would ideally be similar but there are quite a few swallows nests on the joists... wondering if we can get away with an inch or two and serious quantities of super tape around all joins for draughts...
    • CommentAuthorNanuchka
    • CommentTimeMay 21st 2021
     
    WBS an indulgence rather than a staple... was thinking electric heat for day-to-day with WBS for when 'a fire would be nice'!
    • CommentAuthorNanuchka
    • CommentTimeMay 21st 2021
     
    Last question (I think): would on-demand electric hot water be insanely expensive/inefficient for filling an average-sized bath? There is a bath in situ (from the gas boiler days) and would quite like to keep it...
    • CommentAuthorowlman
    • CommentTimeMay 21st 2021 edited
     
    Point of use hot water is very efficient and saves energy by not storing large tanks full of often unused DHW.
    From my own experience point of use is better suited to shower use. If you require enough hot water for a bath then it becomes more difficult, especially with single phase electricity supply. For that sort of thing and with an instantaneous water heater, you'll most likely need a three phase electricity supply with its much greater capacity.

    With single phase supply, and needing a bath, you'll most likely need DHW storage.
    Stick with a nice spacious walk in shower, possibly with a seat, and a high capacity water heater, you'll save both energy and water, IMO. You may also need two instantaneous heaters one for kitchen, e.g. under-sink, and another for bathroom.

    DHW; domestic hot water.

    P.S. Some point of use bathroom water heaters also feature a small amount of storage, e.g. 3-4 gallons, enough to get a shower going straight away, they may well suit your application.
    • CommentAuthorphiledge
    • CommentTimeMay 21st 2021 edited
     
    Posted By: Nanuchka
    We've got 4" PIR going in roof, odd construction makes anything thicker hugely more expensive I think. Floor would ideally be similar but there are quite a few swallows nests on the joists... wondering if we can get away with an inch or two and serious quantities of super tape around all joins for draughts...


    Im not sure 4" in the roof will even comply with building regs let alone be decently insulated. If youre trying to get away with a couple of inches of floor insulation then your likely not going to end up with the "environmentally sympathetic" building youre after. Im no bird expert but Im not sure how long swallows are going to be around if youre working there now??
    •  
      CommentAuthordjh
    • CommentTimeMay 21st 2021
     
    Posted By: NanuchkaWe've got 4" PIR going in roof, odd construction makes anything thicker hugely more expensive I think. Floor would ideally be similar but there are quite a few swallows nests on the joists... wondering if we can get away with an inch or two and serious quantities of super tape around all joins for draughts..

    Don't quite understand where the swallows' nests are? Ah, you mean they're on the floor joists? So in the space you refurbishing? As I understand it that means it's illegal to disturb them whilst they're in use so you would be safest removing them next winter, or make sure you have an expert ornithologist's report describing how you can work around them or whatever, so you can defend yourself if anybody takes action.
    • CommentAuthorphiledge
    • CommentTimeMay 21st 2021
     
    Posted By: djh As I understand it that means it's illegal to disturb them whilst they're in use so you would be safest removing them next winter


    Definitely illegal to try and work round them and likely working on the floor above them could constitute a disturbance too.
    It sounds like an established habitat so if you want an environmentally sympathetic build, it would be best to insulate above the joists after August and leave the habitat in place for future years.
  13.  
    Swallows or not, you want more than an inch or two of insulation in the suspended floor, think ~6" of PIR. Cold feet make everything else feel much colder...! They will fledge by August.

    Have you got your building warrant yet*, will be important to discuss up front if you are not complying with the legal minimum insulation standards? Obviously you should look at compliance, they are for environmental purposes. Also to think about fire proofing the suspended floor and joists above the barn especially if you have machinery in there or loose hay or lambing lamps etc.

    * Or English equivalent?

    Some people have mentioned using a heat pump to heat their whole hot water cylinder up to 40degC or so, you get good efficiency at that temperature. Then run it straight out of their shower head or bath taps without mixing it with any cold water. Particularly effective if you start with the cylinder completely cold, instead of reheating it a little every time you use any hot water. You can heat it with an immersion every so often to prevent legionella.
    • CommentAuthorNanuchka
    • CommentTimeMay 21st 2021 edited
     
    <blockquote><cite>Posted By: philedge</cite><blockquote><cite>Posted By: Nanuchka</cite>
    We've got 4" PIR going in roof, odd construction makes anything thicker hugely more expensive I think. Floor would ideally be similar but there are quite a few swallows nests on the joists... wondering if we can get away with an inch or two and serious quantities of super tape around all joins for draughts...</blockquote>

    Im not sure 4" in the roof will even comply with building regs let alone be decently insulated. If youre trying to get away with a couple of inches of floor insulation then your likely not going to end up with the "environmentally sympathetic" building youre after. Im no bird expert but Im not sure how long swallows are going to be around if youre working there now??</blockquote>

    philedge: what depth of PIR is required in pitched roofs when being upgraded? 100mm will be a massive improvement on what's been there for the last 30 years (something that looks like silver bubble wrap).

    I perhaps could have been clearer: there is no way that we would disturb the area under the floor while the swallows are nesting. And I'm not trying to 'get away with' minimal insulation, I'm trying to come up with a compromise that improves on what's there now, but doesn't affect the nesting of swallows.
    • CommentAuthorphiledge
    • CommentTimeMay 21st 2021
     
    Posted By: NanuchkaAnd I'm not trying to 'get away with' minimal insulation


    ?? You actually said "wondering if we can get away with an inch or two" referring to insulation. Thats pretty minimal and almost certainly falls way short of what you should be aiming for to comply with statutory requirements and an environmentally sympathetic build

    The thickness of insulation you need would normally need would be whatever has been approved by your building control. Im guessing you dont have BC approval.
    The likes of celotex will give you U values for a variety of constructions and a typical minimum build up for a room in a roof scenario could be 70mm between rafters and 40mm over the underside of the rafters to minimise the rafters being a thermal bridge. Thats a minmum that may comply with statutory requirements. As youre asking on a green forum, the expectation would be to better the statutory minimum:)

    As I said, you might be prudent to suspend work while you decide on where youre going and also to let the swallows have some peace:)
    • CommentAuthorMike1
    • CommentTimeMay 21st 2021
     
    Adding heating to a previously unheated space is a 'change in energy status' under the Building Regulations. The building will therefore need upgrading to meet Part L of the Building Regs (conservation of fuel & power) to be legal.

    As for the heating, all electric as others have suggested.
    • CommentAuthorNanuchka
    • CommentTimeMay 21st 2021
     
    <blockquote><cite>Posted By: philedge</cite><blockquote><cite>Posted By: Nanuchka</cite>And I'm not trying to 'get away with' minimal insulation</blockquote>

    ?? You actually said "wondering if we can get away with an inch or two" referring to insulation. Thats pretty minimal and almost certainly falls way short of what you should be aiming for to comply with statutory requirements and an environmentally sympathetic build

    As I said, you might be prudent to suspend work while you decide on where youre going and also to let the swallows have some peace:)</blockquote>

    You may have skipped the part which read: "...there is no way that we would disturb the area under the floor while the swallows are nesting. And I'm not trying to 'get away with' minimal insulation, I'm trying to come up with a compromise that improves on what's there now, but doesn't affect the nesting of swallows." In this context 'get away with' means how much can we get away with adding above nests without disturbing them:) I'm surprised that a member of a green building forum wouldn't be sympathetic to the idea of trying to preserve birds' nests. Am going to bow out now, before you can wilfully misquote anything else, this is stressful and upsetting.

    Thanks to everyone else for the input on the original question.
    • CommentAuthorphiledge
    • CommentTimeMay 21st 2021
     
    Assuming you dont have BC approval, one thing to be very careful of is not meeting the statutory minimum insulation. If BC get wind of the build after youve completed it you may be forced to strip everything out and add insulation to top up to the minimum. If you build to the standards the worse that could happen is an application for retrospective approval with no rework.
    •  
      CommentAuthordjh
    • CommentTimeMay 21st 2021
     
    Posted By: Nanuchkathere is no way that we would disturb the area under the floor while the swallows are nesting

    Note that it's disturbing the swallows that matters. You might do that even working above the floor. Again, p[lease take professional advice.
  20.  
    Just for clarity re my last post:
    For fire safety, you are likely obliged to cover over the underside of the joists with a fire resistant layer, such as thick plasterboard, to provide fire separation between the barn activities and the joists that support the sleeping space. At the same time, you can fix insulation underneath and between the joists.

    You'll obviously leave the swallows to fledge first! And add something for them to nest on next year, ours seem happy to build on any rough surface that is high enough off the ground.

    In the mean time, how about getting an architectural technician round to help with the building control application? They'd advise you about the measures you need so the building complies with the law, for building safety as well as energy conservation.

    The existing energy building regs in England are pretty weak, they are being replaced soon with (somewhat) stronger requirements. As you clearly have got the green building enthusiasm, you'd probably prefer to meet the new standard not the old one! They deal with the overall energy performance of the building, so if it is weak in one area (roof perhaps) you can compensate by making it strong somewhere else (walls?).

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