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    • CommentAuthorJamster
    • CommentTimeFeb 7th 2018 edited
     
    So, I know this is a topic that rightly can provoke discussion, but I thought I'd post this in case anyone has any strong ideas or similar experiences.

    My parents have an oldish (1740 or so) farmhouse with infill stone walls. Windows and doors are generally modernish with a well insulated loft. They've done the easy win stuff but insulation to the walls via EWI or IWI I think is a non-starter for them. Their current CH is via radiators and an oil boiler, DHW generally via an immersion for reasons I'm not sure on frankly. The boiler is old, approx 35 kWth and really needs replacement. Having spoken to them, its not well set up, seems to cycle off and on when manually switched on and while it gets the radiators hot, the building does not stay warm for long once they're turned off. They typically run this for 8 hours a day or so, mainly in the winter and shoulder months. I think I'd struggle to get them to reduce their heat demand through further works.

    They use approx 2000 litres of heating oil a year which I think is an approx heating demand of 20,000 kW; I have no idea of their DHW usage but I doubt it is huge (2 showers a day).

    They had a SAP done when they got the loft insulated for free but I haven't seen it yet.

    Replacement options.

    No mains gas supply.
    Heat pumps are ruled out I think - no desire to replace rads with UFH, flow temps on rads will kill the CoP on a heat pump.
    I would prefer not to get a replacement oil boiler as the fuel is expensive.
    Biomass - suggested option at the moment but probably pellets rather than manually fed logs (they're in their 60's).

    So, I am going to suggest that they investigate a 40-50 kW output biomass boiler linked to a large heat bank / buffer tank (approx 1500 - 2000 litres) that can do batch burns to increase the efficiency and use this to serve the CH system basically via either "always on" at a lower flow temp or at least a longer CH period to try and steady out the heating period. Or would a smaller (and cheaper) burner be better, given it would have to run for longer? Any thoughts? Either way, a large hopper I thiink is necessary as it seems to give a better position when placing orders pellet suppliers.

    My other query is mainly around DHW at the moment - should they look to take the DHW via a heat exchanger at the top of this buffer tank (plenty of pressure for mains fed) or fit a seperate smaller tank for year round DHW supply so that in the summer only this is heated? I assume this isn't difficult? I've seen it suggested that the DHW is also fitted with an immersion that could do DHW via PV in future also.

    This would reduce the need to disrupt the house significantly and the existing CH and DHW loops could feed straight from the new tanks. Annoyingly, this would likely need a plant room outside, but it could well be cheaper and easier than trying to fit one into the house.

    EDIT: I forgot to say that RHI is an option but obviously accreddited equipment and suppliers will push the cost up in the first instance so again, comments on this welcome.

    Experiences and recomendations welcome. Thanks - Jamie
    • CommentAuthorArtiglio
    • CommentTimeFeb 7th 2018
     
    Had a similar situation with my mothers house, stone farmhouse mid wales, heat demand is 35,000 including hot water. This was 3 years ago. Went for it under rhi. 40kw boiler (this is really too big but was fullfilled the rhi requirement and range available, 25kw and a larger buffer would have suited better) 1000l buffer, pellet boiler, self built 7t store. All up installation cost 24k not including my labour , this had increased costs of around 4k because the boiler is in a barn 30m from house.
    Boiler installed is a trianco greenflame (iirc) which is a rebadged polish egogren. Very basic agriculturally engineered piece of kit. That said once settings were finessed , pellet brands tried (blazers are rubbish, land energy far superior, at least in this boiler) AND lots of time spent improving the installed insulation levels on buffer, pipework etc. It’s worked well, few teething issues with ignitors and feed augur but now these are known they can be monitored. However boiler was sold as being needing one annual service but this soon changed to 6 monthly ( argued this point as breach of contract and got goodwill reduced servicing price).
    There’s no way my mum could look after it on its own , but i keep an eye on it every 8 weeks and its fine.
    Funds allowing I’d go for a much better boiler but that would have been an extra 6k plus. Weather compensation would have been a good option. This was all based upon the rhi figues at the time which by the time the 7 years are up will mean payments will exceed the initial installation and servicing costs by about 9k. Pellet consumption has averaged 7.5t per annum. However the house has 3 wood burners as space heaters and these tick over during the winter.
    I hindsight would I do it again, probably not especially with current rhi rates , pellet price / supply uncertainty ( not caused a problem yet but bit of planning required). The property already had an LPG tank and putting a good gas boiler in would have been much cheaper and something that would need far less attention.
    However if you were to give rhi a miss and can find a good installer who is either willing to fit kit you source or import for you , there are good package deals available on the continent, but it all adds to the hassle.
    Those who got on the rhi bandwagon at the start and could get a simple system installed will have done very well.
    The house has an attached annexe, so effectively 2 seperate heating systems, the incoming supply from the buffer, feeds the 2 sytems via heat exchangers and the heating systems are conventional radiators and hotwater tanks. Whilst heat exchangers are not the most efficient, the advantage of seperating the the two heating systems and the boiler buffer circuit into 3 seperate circuits makes life a lot easier and prevents contamination from the old heating circuits.
    System losses mean that if there is going to be no heating demand then using immersion heaters for hot water is probably more cost effective, but boiler is rarely switched off.
    •  
      CommentAuthorSteamyTea
    • CommentTimeFeb 7th 2018
     
    Oil is not so bad, a lot better environmentally than biomass, and probably cheaper to install/replace and run.

    You could just get the heating system sorted out properly, or at least sketch up the current design and let people on here have a look.

    Showers could be done with a relatively cheap electric shower unit. Just make sure you size it right so that is is pleasant to use.

    Have a look at the newer generation of CO2 heat pumps. They can reach a higher temperature than the current ones (which are being phased out anyway).

    What is important is to get a decent idea of the actual heat loads. Without that you can't size a system properly. This is true for any heating system.
  1.  
    Jamster - You seem to be leaning towards a wood pellet system - why? The cost of a pellet system can be quite high (see above post) and fuel would have to be sourced probably several times a year. I would agree that getting a log burner at the age of 60+ is probably not a good idea.

    However the other options would be a new oil boiler or a LPG boiler. A quick look at comparison on the internet showed that oil had a per kW price of 7p whilst pellets had a price per kW of 4.1 (LPG came in at 9p/kW and as you already have an oil tank this is probably ruled out) It would take a long time to recover the extra conversion cost in going over to a pellet system from the kWh savings on fuel costs, especially if you have to build an external plant room.

    I would expect a modern condensing oil boiler to give savings over your old boiler. I can see that staying with an electric immersion heater makes sense for DHW as E7 (or similar) would be cheaper than oil and in any event it is better to separate CH and DHW (If you do go down the pellet route then have a separate DHW tank). As an alternative to a pellet perhaps get a new condensing oil boiler swapped in to your existing system and with the money saved (from not buying a pellet system + installation costs) get some PV.
    • CommentAuthorgyrogear
    • CommentTimeFeb 7th 2018 edited
     
    <blockquote><cite>Posted By: Peter_in_Hungary</cite>getting a log burner at the age of 60+ is probably not a good idea.</blockquote>

    could not disagree more !
    It's like saying, when you get to 67.5 yrs, get rid of the garden...
    ... or when you get to 72.4 years, get rid of the pushbike...
    ... when you get to 59.2 years, stop diving...
    ... and at 64.97 years, you are *far too old* to be on a sailboat...

    We are going to live to age 120, for Krike's sake !

    I got my wood stove aged 62 ! My only regret is we waited too long, with a smoky open fireplace...
    I am now 66 and counting, and the log stove is the best investment we made !
    It is five-star, and I intend to change it for a 7-star, and install a heat-recovery air pipe.

    I have a lad bring me 1.5 stères once a year, for 90 Euros, and the rest I cut myself - I reckon that we burn one-half for heat, and the other half for fun & social, and I don't need to cycle or run to keep fit !

    I take pride in running the stove up to operating temp (150°C) in under 10 minutes so it don't smoke; my record is six minutes !

    Everybody around where I live burns wood.

    I built two solar wood driers: today was 7°C out, and the log driers were at 21°C.

    To dissolve the microparticles, we just... drink :devil:

    Have a good time, carpe diem : life is short and you're a long time dead...

    gg
    • CommentAuthorArtiglio
    • CommentTimeFeb 7th 2018
     
    I just checked the rhi rates, we got 10.98p / kwh and current is 6.54p. So given the costs involved financially not worth it, environmentally no real benefit and likely to be more effort to look after. Unlikely biomass will offer any comfort or convenience over oil. Only sure winner will be govt and the notional co2 savings it will claim your system makes.
    If i were in your shoes, new oil boiler, upgrade controls, weather compensation, maybe look at how dhw is done, and as suggested add some pv, and or look at more insulation etc.
    • CommentAuthorgravelld
    • CommentTimeFeb 7th 2018
     
    Posted By: JamsterI forgot to say that RHI is an option but obviously accreddited equipment and suppliers will push the cost up in the first instance so again, comments on this welcome.
    Yep, and the requirement to purchase the pellets from certain suppliers will also call into question your characterisation of biomass being cheaper than oil as a fuel. Who knows what will happen in the future?

    The only real answer without a crystal ball is demand reduction.
    • CommentAuthorJamster
    • CommentTimeFeb 7th 2018
     
    Hi again,

    Thanks for your comments - I don't know why I didn't give more thought to a replacement modern oil boiler. Bandwagon fever perhaps. I also thought perhaps it would be cheaper to run and they'd live the CH on for longer, which is what I think the house needs. Demand reduction would be better of course gravelld but I think they'd rather be cold than have IWI or EWI upheaval. They're a bit stubborn...

    Thinking a bit more - I think I'd almost assumed that it is worth getting a biomass boiler and qualify for the RHI to essentially get a 'free' system in place after 7 years and that because the boiler basically became free, the lower per kW price for pellets was all that mattered...

    Is biomass worse than burning oil environmentally - its an interesting argument. If a sustainable / uk source of biomass could be secured, is it not a better, more renewable option?

    Anyway, re the parents, the suggestion could essentially be a straight swap with perhaps a better, less hacked about over the years setup for the CH and DHW, possibly with a PV input for summer DHW. Typically, would it be better to have a buffer tank for an oil boiler or just let it heat the rads directly? I know the proper answer is to ask a heating engineer, but it makes a difference if they'd need a new outbuilding or not.

    Artiglio, interesting that you'd likely not go down the same route again - says a lot in itself given it sounds a similar setup. Gyrogear, well said, nothing implied re their fitness, they're still running a farm so I think that's enough for them and I'm hoping that this is a 20-year solution for them too. Don't let me do you down!

    Peter, Steamy, thanks for your thoughts also - I do need to find their SAP I think and get a better measure of their heat demand. Its a typical older farmhouse though - big rooms, high ceilings, stone walls. Lots to heat up.
  2.  
    Posted By: gyrogearcould not disagree more !
    It's like saying, when you get to 67.5 yrs, get rid of the garden...
    ... or when you get to 72.4 years, get rid of the pushbike...
    ... when you get to 59.2 years, stop diving...
    ... and at 64.97 years, you are *far too old* to be on a sailboat...

    At 70 this year I do all of the above (substitute the occasional dive for the sailboat) and I also run a farm. We have had a log burner for the CH for the last 23 years.
    My point is that adding a log burner for CH builds in a 'must do' into your life at a time when things an be unpredictable. Two of my friends (similar age to me one in the UK one here) had what they thought was a pulled muscle only to find that they needed a coronary bypass. The list above is all optional, you an reduce the size of the garden or cycle less, take the bus more etc.. If you install log burning CH you are stuck with the 'must do' for a long time or be faced with an expensive change down the road. A neighbour of ours heated with wood and the social worker had to bring in the wood every other day because the were no longer capable but in other respects they were (more or less) independent. I would much rather have things I could manage down over the next 20 years rather than build in something now that was a 'must do' and if I could not 'do' then it would threaten my ability to live where I am.
    • CommentAuthorJeff B
    • CommentTimeFeb 8th 2018
     
    Jamster – we fitted a wood pellet boiler to replace an aging oil boiler in Sept 2014 and we got a pretty good deal using the RHI scheme. (Approx £2200 p.a. for 7 years). It is fine whilst I am around (I’m 71 this year) but I know my wife would not be able to cope with it if I “go” before her. The boiler manufacturer claims it to be low maintenance (self cleaning etc.) but that is simply not the case. I have to give it a thorough strip-down clean very month which almost equates to the annual service in terms of work to be honest. I know my wife could not do that. It is a filthy job carried out on my hands and knees. You don’t say how old your parents are but I suggest they would need to consider that aspect.

    We have a buffer tank that supplies the C/H system and a separate, sealed, indirect, DHW tank with a solar coil. If I was doing this today I would not phaff about with a glycol solar thermal system but get an Immersun type gizmo, then use my PV panels to run the immersion heater.

    Our RHI payments cease at the end of 2021 and, God willing, I will be 75 in the spring of 2022. We may then seriously have to consider whether we continue with the pellet boiler with its regular maintenance schedule or revert to oil once again with a once-a-year service carried out by someone else.
    • CommentAuthorgyrogear
    • CommentTimeFeb 8th 2018 edited
     
    Posted By: Peter_in_HungaryIf you install log burning CH you are stuck with the 'must do' for a long time or be faced with an expensive change down the road.


    Hiya, PiH !

    Of course I agree entirely !
    (I was actually surprised to find myself saying I disagreed, LOL).

    However, in my case, the wood burner does have a back-up already - namely, the electric radiant floor that we no longer use...

    All it takes is a visit by the leccy board, to UP the main C/B from the 9 kVA I ordered, back up to the 12 kVA it had been at for 30 yrs...

    All I then have to do is calculate the respective disadvantages from breathing particles, to walking around (and sleeping) in an EMF haze...
    :shamed:
    gg
    •  
      CommentAuthordjh
    • CommentTimeFeb 8th 2018 edited
     
    Posted By: gyrogearAll I then have to do is calculate the respective disadvantages from breathing particles, to walking around (and sleeping) in an EMF haze

    There's not much EMF from a mains frequency source. The most noticeable effect is a magnetic field and I've only ever seen that affect anything once. I used to work in a basement office, and the mains inlet for the six-storey building passed underneath that office. CRT computer screens had a noticeable wobble on them in that room. So they had to move us out :)
  3.  
    Posted By: djhThe most noticeable effect is a magnetic field and I've only ever seen that affect anything once. I used to work in a basement office, and the mains inlet for the six-storey building passed underneath that office. CRT computer screens had a noticeable wobble on them in that room. So they had to move us out :)

    Are you sure that it was the screens that had the wobble and not your eyes:devil::devil:
    •  
      CommentAuthorSteamyTea
    • CommentTimeFeb 9th 2018 edited
     
    Posted By: Jeff BSept 2014 and we got a pretty good deal using the RHI scheme.
    Jeff, have you kept easily accessible records of the prices you have paid for the pellets over the years.
    I usually see the Nottingham figures quoted, but they are average figures.
    • CommentAuthorJamster
    • CommentTimeFeb 9th 2018
     
    Posted By: Jeff B The boiler manufacturer claims it to be low maintenance (self cleaning etc.) but that is simply not the case. I have to give it a thorough strip-down clean very month which almost equates to the annual service in terms of work to be honest. I know my wife could not do that. It is a filthy job carried out on my hands and knees. You don’t say how old your parents are but I suggest they would need to consider that aspect.

    We have a buffer tank that supplies the C/H system and a separate, sealed, indirect, DHW tank with a solar coil. If I was doing this today I would not phaff about with a glycol solar thermal system but get an Immersun type gizmo, then use my PV panels to run the immersion heater.


    Thanks Jeff - I was definately wanting something 'light-touch' so that's another vote against biomass to be honest. I think whatever they go for should have a PV input for an immersion in the summer when the the main heat supply might not be needed. The other thing to mention here is that they have an electric AGA... I know, I know.... In their defence, its a 40-year old one that was converted from solid fuel to oil and from oil to electric, and probably their main luxury!
    • CommentAuthorowlman
    • CommentTimeFeb 9th 2018
     
    I don't think you've mentioned Air/Air heat pumps; from your initial description I assume you meant Air/Water.
    I have biomass but I opted for a slightly different control system inasmuch as the CH pump stays on 24/7 for the 5 or 6 months of the heating season. The house temp is controlled, not by the pump and or some boiler switching on and off, but by the temp of the circulation water. Sometimes this is barely warm other times hot.
    By keeping the house constantly heated all winter in this manner I think has resulted in a home that is always warm.
    In your case an Air/Air system running 24/7 may provide that basic background warmth with something else conventional providing boost, perhaps in selective areas, should it be needed.
  4.  
    Posted By: JamsterThe other thing to mention here is that they have an electric AGA... I know, I know.... In their defence, its a 40-year old one that was converted from solid fuel to oil and from oil to electric, and probably their main luxury!

    Agas are a bit like wood burners - they are a lifestyle issue / choice
    • CommentAuthorJeff B
    • CommentTimeFeb 12th 2018
     
    <blockquote><cite>Posted By: SteamyTea</cite><blockquote><cite>Posted By: Jeff B</cite>Sept 2014 and we got a pretty good deal using the RHI scheme.</blockquote>Jeff, have you kept easily accessible records of the prices you have paid for the pellets over the years.
    I usually see the Nottingham figures quoted, but they are average figures.</blockquote>

    Yes I have. I keep a running list with all my invoices. These are the Pembrokeshire prices (£/1000kg) from Nov 2008 to date:

    Nov 2008..170
    May 2009..170
    Jan 2010..173
    Sep 2010..187
    Jan 2011..187
    Dec 2011..215
    Apr 2012..219
    Nov 2012..219
    Feb 2013..219
    Nov 2013..219
    May 2014..219
    Mar 2015..238
    Feb 2016..238
    Feb 2017..228
    Feb 2018..238

    The cost has increased 40% over the 10 years. I don't know the justification for this increase (if there is any?).

    Jeff
    • CommentAuthorJeff B
    • CommentTimeFeb 12th 2018
     
    <blockquote><cite>Posted By: owlman</cite>I don't think you've mentioned Air/Air heat pumps; from your initial description I assume you meant Air/Water.
    I have biomass but I opted for a slightly different control system inasmuch as the CH pump stays on 24/7 for the 5 or 6 months of the heating season. The house temp is controlled, not by the pump and or some boiler switching on and off, but by the temp of the circulation water. Sometimes this is barely warm other times hot.
    By keeping the house constantly heated all winter in this manner I think has resulted in a home that is always warm.
    In your case an Air/Air system running 24/7 may provide that basic background warmth with something else conventional providing boost, perhaps in selective areas, should it be needed.</blockquote>

    Can I ask please, what is your heating demand and how many tons of pellets you use p.a.? I went through a similar exercise some time back of keeping the boiler on overnight on the theory that by keeping the house temperature "ticking over" overnight (rather than allowing the building fabric to cool overnight) this would reduce the overall pellet consumption. It certainly did not in my case!
  5.  
    Posted By: Jeff BThe cost has increased 40% over the 10 years. I don't know the justification for this increase (if there is any?).

    A quick and dirty count shows that taking the average inflation over that time an increase to 215 GBP could be expected so the actual rise is about 1.5 times inflation:angry:
    • CommentAuthorowlman
    • CommentTimeFeb 12th 2018
     
    Hi Jeff B,
    Apologies I didn't specify, I burn log-wood not pellets. I was using the 24/7 heating bit to illustrate the option of having a constant background heat (e.g. heat pump), which his elderly parents could supplement, as required, with other means.
    •  
      CommentAuthorSteamyTea
    • CommentTimeFeb 12th 2018
     
    There was some concerns about the price a few years back when the RHI was introduced.

    At £238/tonne, I think that is around 5p/kWh (using 4.8 kWh/kg).
    E7 is about 8p/kWh

    So not much difference is running costs after efficiency is taken account of and you don't have the storage issues or the maintenance to worry about.
    • CommentAuthorJeff B
    • CommentTimeFeb 12th 2018
     
    <

    Posted By: SteamyTeaThere was some concerns about the price a few years back when the RHI was introduced.

    At £238/tonne, I think that is around 5p/kWh (using 4.8 kWh/kg).
    E7 is about 8p/kWh

    So not much difference is running costs after efficiency is taken account of and you don't have the storage issues or the maintenance to worry about.


    Yes there was. However from Dec 2011 to May 2014 the cost was pretty static, then suddenly a 10% jump and pretty static since then.

    Heating oil is currently about 50 p per litre here, so about 5 p per kWh (using 10 kWh/litre). Pellets are 24p per kg, so about 5.3p per kWh. Oil prices are creeping up again so there is almost parity between them, which I'm happy with. For quite a while oil has been much cheaper in terms of pence/kWh than wood pellets - I'm amazed that there is any market for wood pellet boilers!
  6.  
    Our farmhouse is similar build to your parents although a bit older at around 1650. 600mm loft insulation and 3G windows direct into the stone mullions. Heated at present with 20kw Dunsley Yorkshire with Esse Range doing cooking and DHW. Dunsley Highland in snug. At present doing a refurbish with old age in mind. The central heating is being modified from radiators throughout to UFH downstairs and radiators upstairs. UFH will be both wet and elec to give options and flexibility in the future. The Esse will be replaced with a pellet/log Lohberger capable of doing both DHW and Central Heating.
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