Navitron Renewable Energy and Sustainability Forum

Energy/Electricity Storage and Use/Grid Connection => RHI (Renewable Heat Incentive) => Topic started by: M on September 29, 2019, 02:51:32 PM



Title: Advice needed on 'greening' an existing building
Post by: M on September 29, 2019, 02:51:32 PM
Hello all.

My sister and family are moving, and changing lifestyles quite a bit, with a property with an agricultural leaning.

It's a biggish property that's been extended a few times, and currently has two oil boiler based heating systems, as it can effectively be regarded as two halves.

It has no gas supply, but I suspect it either has 3 phase, or has it running right outside.

The whole electrics and heating systems need replacing, and she's asked me for advice on what renewables approach she can take, as she has (not a lot) but some spare monies based on the respective prices of old and new home.

Straight off, I thought of RHI, but wasn't sure if it would have a good enough EPC rating, but the more I research, I can only find a need for an EPC (to prove it's domestic), no mention of a required EPC level - is that right?

If RHI is possible, then I'm thinking with ages north of 50, biomass might not be ideal, as they won't want to be shifting bags of pellets in 20yrs time, or I might be overthinking it? So ASHP or GSHP, is there any reason not to think of going down that/those routes?

She's also asked about PV, and there is a large south facing roof, and I believe if your property is agricultural, then PP is not an issue, so ground mounts, barns for rooves etc.. My immediate thought would be to go as big as budget allows, especially if 3 phase, so 10kWp+, as that will help a bit with HP heating, and perhaps charge BEV's in the future?

Not sure about batts at this stage, but certainly something to watch?

Any general thoughts and ideas? Chat and comment welcome as always. Also, to all and Navitron, any suggestions for good contacts re RHI, MCS installers etc willing to visit S. Wales?

Many thanks, Martyn.


Title: Re: Advice needed on 'greening' an existing building
Post by: brackwell on September 29, 2019, 03:33:06 PM
Not much responsiblity there then Mart.

These days I always think of a boiler as a just in case insurance policy.  However if one is not going down the eco route then why not just replace the oil boilers but if going down the eco route then why waste money on something you are trying to use so little of.  For me it would be GSHP, loads of PV and you guessed, loads of insulation/draught proofing. Starting with getting rid of fireplaces and chimneys.

The biggest problem is that to claim the RHI you need to have MCS certification which means it needs to be able to maintain good efficience COP 3 ? and 21C in virtually all rooms in the worst winter etc, something i very much doubt you could achieve without HUGE additional expense. Now if you know someone with a digger then...

I do wonder how TOU tariffs change matters with Batts, HPs and even storage heaters.

Ken



Title: Re: Advice needed on 'greening' an existing building
Post by: titan on September 29, 2019, 04:39:13 PM
I am surprised that someone with over 5000 posts is asking for general renewable advice for a property based on  "it's a biggish property that's been extended a few times" it just raises a load of basic questions, like what is the energy requirement, do they want to dig up floors for UFH or some of the land for GSHP pipework is it a quiet site would an ASHP be intrusive, how well insulated is the property, what is the current energy use, oil I assume how many ltrs a year any open fires any wood burners the list goes on.


Title: Re: Advice needed on 'greening' an existing building
Post by: todthedog on September 29, 2019, 07:17:30 PM
I think Mart is doing this for two reasons
A fresh point of view
Help for others lacking in experience
A more considered reply when I have a proper keyboard.


Title: Re: Advice needed on 'greening' an existing building
Post by: ecogeorge on September 29, 2019, 07:39:33 PM
I would ..........
-insulate , insulate and insulate .
-then insulate a bit more -just in case ........
-As much pv as you can fit .10kw or more ........
-Big thermal store with inputs for GSHP (run on pv during day ), wood burners , pv diversion controllers.

Do you have a wood supply ? are you willing to stoke fires ?? cut wood ??
Can you install GSHP -I did it -you can -thread somewhere here but old now..........
I would have say 20kw back boiler wood stove with surplus pv and GSHP as back up. Run GSHP say 10am-4pm  (3kw input -9kw output at cop 3).
Surplus pv to immersion heater (s).
Personally i would forget oil or gas but be prepared to run a woodburner hard when required.
any windturbine options?? not huge input but nice to watch and give a smug feeling.
any streams ? hydro ??
Mofe pv ??? -its so easy and cheap.
RHI -would forget about -so dear -new kit, specialist installers to sign a bit of paper .
George.


Title: Re: Advice needed on 'greening' an existing building
Post by: rogeriko on September 29, 2019, 10:21:51 PM
RHI is now only feasible on a GSHP. Unfortunately GSHP's and old farmhouses dont mix.


Title: Re: Advice needed on 'greening' an existing building
Post by: M on September 30, 2019, 07:46:30 AM
I think Mart is doing this for two reasons
A fresh point of view
Help for others lacking in experience
A more considered reply when I have a proper keyboard.

Yes, and many thanks.

But also, i don't have full info yet, just basic chats with my big sis, though we will have a sit down on Wednesday for me to run through options and ideas. I've asked her to bring building specs and EPC, and she's hoping to do a site visit today (I can't go, got cat rescue cleaning, dog boarder going (sniff, cry) and a fever). I asked her to note where the leccy supply is for 3 phase.

But, and sorry titan, but whilst I love chatting about all things renewable, I have very little practical experience outside of PV, so I need real input from real do'ers, especially regarding pro's and con's.

At this stage I was opening the door for any and all info, and will of course update with more details as I get them.


Ecogeorge - a WT hadn't occurred to me, I need to see the site, and presumably how it lies regarding wind from the SW(?), but I don't know anything about wind, just the hard work many on here have reported it to be ..... plus fun of course.

I suspect this is more evidence that we need a professional to offer suggestions and advice, and some budgetary ideas. Again, suggestions welcome/appreciated?


Rogeriko, can I ask what you mean, are you saying ASHP might not be doable/available now?


Title: Re: Advice needed on 'greening' an existing building
Post by: benseb on September 30, 2019, 07:44:30 PM
Of course ASHp is feasible if GS is

If you have the land to do a ground array go with GS. Otherwise AS

Our RHI will be approx £11,000 over 7 years so will pay for the entire heating system (14kw ASHP plus new DHW tank)

RHI pays out more for energy hungry houses

But insulate lots anyway (after youíve done the EPC) to lower your carbon and costs and be more comfortable.


Title: Re: Advice needed on 'greening' an existing building
Post by: rogeriko on September 30, 2019, 11:56:21 PM
Ashp earn 10p per kw and gshp earn 20p per kw RHI.   https://www.ofgem.gov.uk/environmental-programmes/domestic-rhi/contacts-guidance-and-resources/tariffs-and-payments-domestic-rhi/current-future-tariffs

In very cold weather and damp conditions ashp's tend to ice up a lot so even though the compressor is running it is not heating the house.


Title: Re: Advice needed on 'greening' an existing building
Post by: M on October 01, 2019, 07:49:07 AM
Ashp earn 10p per kw and gshp earn 20p per kw RHI.   https://www.ofgem.gov.uk/environmental-programmes/domestic-rhi/contacts-guidance-and-resources/tariffs-and-payments-domestic-rhi/current-future-tariffs

In very cold weather and damp conditions ashp's tend to ice up a lot so even though the compressor is running it is not heating the house.

Thank you. I had seen the subsidy rates, but also understood GSHP was about twice the price, so roughly balanced?

However, I also understand(?) that as GSHP is more stable, then it's a safer bet for those occasional extreme times. I was going to suggest that they also add one or two small AC units, like my ickle one, that way they can have some localised cooling as I've been told RHI isn't available if the main system is used for cooling too.


Title: Re: Advice needed on 'greening' an existing building
Post by: brackwell on October 01, 2019, 08:33:07 AM
Mart,
I do not believe a solid house made from stone,concrete etc needs AC. The thermal mass makes a good job of stabalising temps.

Have you researched my comment that you will have difficulty achieving a MCS system for the purpose of RHI ?

Ken


Title: Re: Advice needed on 'greening' an existing building
Post by: Moxi on October 01, 2019, 09:02:56 AM
Morning Mart,

I would have to say the first thing I would do would be to get the external walls insulated - for us, in our exposed west facing stone cottage, this eliminated a lot of draughts that had previously thwarted our attempts at eliminating.  At the same time we laid in over a meter of loft insulation and almost over night the house became notably warmer to the point of being comfortable, condensation and mold issues were almost totally removed as well with just one or two spots which required further intervention.

After that we had time to deal with the internals, without being really cold for around 8 months in the year, so being able to live in one section of their property adequately warm and comfortable while they strip out and renovate another section may appeal to your sister and family and compliment their funds for the project?

 
Moxi


Title: Re: Advice needed on 'greening' an existing building
Post by: todthedog on October 01, 2019, 12:15:38 PM
Good morning Mart
Only can tell you what we did, what works and what didnt.

First of all the house it was about 150 m2 construction  stone earth bound 1.5 m thick walls, slate roof no insulation. The wind used to blow through  the walls, single glazed windows. In Finisterre . Money was a large restraint.

Shed loads of insulation in the roof.
Walls repointed with lime mortar.
Dry lined stud and track plasterboard with rockwool. PIR not available in France. Clockman did similar but with plasterboard with insulation attached.Not a solution that would work for us as there wasn't a single straight wall the place. Both of these with photographs are available on the site somewhere.
Windows replaced by double glazed (French b&q) All well sealed as was dry lining.
Heating wood burner with stainless liner up the existing chimney, which was sealed and insulated. This was supplemented by an air/air ashp used in  the shoulder months and worked brilliantly.
Solar thermal again worked fabulously.  200 l tank 'free' hot water for 9 months of the year. If this had been the UK not France I think that I would have gone with an instant electric shower and water heater, not a workable solution in France due to the vagaries and cost of electric supply. No stored hot water at all.
6 kW of PV again due to the peculiarities of the French system we sold half and used half so all our costs were more than covered.
2.5kW wind turbine good experience and fun essential if you were off grid but more pv and some battery back up might have been better in our case. Or a big thermal store a la Biff.
Small continuously running extract fan low energy used about 3 euros a year in the kitchen lounge no humidity problems.

Good luck



Title: Re: Advice needed on 'greening' an existing building
Post by: M on October 01, 2019, 12:17:26 PM
Hello again guys and girls.

Looking forward to getting some more specs tomorrow. I seem to recall the EPC is an E with C potential, but will need to see and have a read.

From short chats and a slightly confusing phonecall, I think the newer parts have CWI, but I don't know about the older parts. We had CWI probably 15+yrs ago and it's simply brilliant. Just done my stats for end of Q3, and if Q4 is average for gas consumption, then we'll be looking at just 6,000kWh's this year (including oven and DHW), not bad for a 1930's British semi. First day we've needed heating on here, and that's just a marginal little bit of top up, and all from the ASHP (air con) and 'free' PV.

I've also pondered a two stage build out, but as there will be investment money at the start (new property slightly cheaper than old) my sis is looking to put most 'stuff' into storage, allowing for a clean house for leccy and heating works, which is another reason why now seems to be the time to consider ideas to slot in ...... budget allowing.

Thanks Tod, posts crossed.


Title: Re: Advice needed on 'greening' an existing building
Post by: benseb on October 01, 2019, 01:46:19 PM
Ashp earn 10p per kw and gshp earn 20p per kw RHI.   https://www.ofgem.gov.uk/environmental-programmes/domestic-rhi/contacts-guidance-and-resources/tariffs-and-payments-domestic-rhi/current-future-tariffs

In very cold weather and damp conditions ashp's tend to ice up a lot so even though the compressor is running it is not heating the house.

Thank you. I had seen the subsidy rates, but also understood GSHP was about twice the price, so roughly balanced?

However, I also understand(?) that as GSHP is more stable, then it's a safer bet for those occasional extreme times. I was going to suggest that they also add one or two small AC units, like my ickle one, that way they can have some localised cooling as I've been told RHI isn't available if the main system is used for cooling too.


We had a big dilemma about AS vs GS heat pump.

On paper GS is better. More stable at low temps, better COP

However

It can be riskier (if ground array is too small lots of work to increase). Also often if the system isnít specced  correctly you donít realise until year 3 onwards.

Saying that we still would have gone for GS if we had the land for horizontal pipes. Probably.

As we didnít, boreholes were going to cost an extra £10k so made it so much more of an upheaval and increased the risks if they werenít sized correctly.

In the end we went with ASHP. We got a decent brand (Mitsubishi) and the COP ainít that much different to what we were quoted on GS.

£10k less RHI but £10k cheaper.

Not had a cold winter to test yet but so far it just works and is keeping us warm 24/7 rather than for 4 hours a day that our oil boiler ran for!

At work we have 3 ASHP. During beast from the east they maintained their temperatures fine. The only issue was the UFH that had been installed by a cowboy with 1 inch chipboard on top.... so didnít give out nearly as much heat as it should. But that wasnít a fault of the heat pumps.


Title: Re: Advice needed on 'greening' an existing building
Post by: M on October 03, 2019, 08:41:32 AM
OK, a bit more meat to put on the bones. May be a bit hap dash I think of things.

The property is slightly on the large side at approx 15m across the front and 9m deep. Two storey. Large roof and no plans/need to use it.

It is currently served by two oil boilers, reflecting the extension (approx 1/3rd), but both boilers are questionable at this stage.

Old building may well be single skin, extension is double skin, probably no CWI, though of course it envelops/removes the original single skin end wall on that side.

A lot of work is needed on the building internal and external. Including a complete new septic tank, re-wire and kitchen, probably around £100k.

Now for the good news, I hope. My sister is open to ideas and major work. they will be storing the vast bulk of their 'stuff' and will, as she describes it, be camping out in the new house to keep it all empty and available. She's also aware that a lot of time will be needed and when I suggested a second winter might break them, she said that was their plan too to hopefully be complete by Sept 2020.

From there, plus the fact that all rooms need redecorating, plus walls and ceilings are simple no complicated architrave, I suggested that IWI of 100mm PIR would be ideal across the external walls of each room - seems like the right time to do it?

I mentioned no plans for the loft, so that should simply be a matter of chucking 400/500mm(?) of 'fluffy' insulation down, and issues there?

Onto leccy supply, it is single phase but she took some photos of the pole across the road from her where the wire comes in, and it also has about five lines all going into the farm/business/yard whatever it is they are/do, which suggests to me that that pole has three phase, would that be a fair assumption? Obviously a bit more research needed though.

Next we move on to PV. The front roof is one single long roof, faces SSE, with two chimneys at the top/back (so north to panels. It is 15m wide and at a guess, from the depth of 9m and the average looking pitch (30-40d) I'd suspect 6m or more in height. So at 14 panels wide and 3 panels high and lowish (now) 300Wp, that would be 12.6kWp, so a figure around 10kWp would look easy, again depending on three phase. I've seen more Pv quotes (on MSE) getting closer to £1k per kWp, and a few going under when installs are 6 or 7kWp, so I've suggested a price for 10kWp of around £8k, possibly £10k.

The economics of the PV are surprisingly good, I guessed at 10,000kWh's, with 3-4k consumed, as the house will have leccy heating (back to that later) and DHW, so around 3,000 x 15p savings, £450, and export, hopefully of 7,000 x 5p, £350, giving £800 pa.. They almost certainly will be moving to BEV(s) in the future, so additional benefits possible.

Now for heating. Obviously we need to do more research but ASHP could be good. Especially combined with IWI and plans for one or two wood burners anyway, but which are not planned for heating the house, just top up. Looking at photos some rads are doubles, but closer look needed, and whilst it's tricky to work out from photos, the pipework certainly doesn't look like microbore to me, possibly 15mm, could be 22mm. Good chance rads (or at least some) need replacing anyway, and back to the empty house / camping, all seems to fit nicely as the time to do it, and do it properly.

Regarding ASHP costs, excluding rad work, i simply stuck a wet finger in the air and said that suggestions are £6-£8k, so given property size, and erring on side of caution, perhaps £12k to £15k as a guide. I did explain that a bigger size will push up costs, but bigger size means more heating needs, which in turn pushes up the RHI side.

So where am I going wrong? What am I missing? Does the entirely basic plan at this stage make sense? what else could we consider (she would like a WT, but I'd guess it neds to be a biggish one so that she can forget about it (to a degree), and this might be something for the future?

All thoughts welcome. Thanks guys and girls.


Title: Re: Advice needed on 'greening' an existing building
Post by: Countrypaul on October 03, 2019, 09:31:21 AM
Whats the construction, you mention single and double skins, but nowhere I spotted indicates what these are made of or how thick they are etc. Are the ground floor suspended or concrete onto earth (or insulation) or stone tiles onto earth? How do services enter/leave the house, if there are lots of pipes going through the walls much more possibility of air leakage. What are the windows like (again I didn't see any comments about them but may have missed any).

Have you created a spreadsheet to work out estimated heat requirements and what effect the various changes might make?  Best to model the effect of any changes before deciding whether to implement or not.


Title: Re: Advice needed on 'greening' an existing building
Post by: benseb on October 03, 2019, 10:21:26 AM
Our House is twin walled stone and brick with 50mm IWI and is toasty, except for the lounge which is a bit drafty so need to fix that

If you can, it might be worth leaving some stone work revealed to help with thermal mass. Then when you get a very cold day you have a chunk of stone at say 20c radiating heat. Assuming youíve kept the room up to temp constantly

Ideally an internal wall so itís not bridging cold from outside.


Title: Re: Advice needed on 'greening' an existing building
Post by: bxman on October 03, 2019, 11:05:12 AM
 I suggested that IWI of 100mm PIR would be ideal across the external walls of each room -

 Sorry to disagree Mart .

  BUT all internal walls running off the the exterior wall will be a thermal bridge as will be  any of  the floors and ceilings joined to the external walls.

If at all possible go with EWI .

The structure of the house then becomes a  thermal store helping to modulate the house temperature through out the year .

good luck cheers Patrick


Title: Re: Advice needed on 'greening' an existing building
Post by: M on October 03, 2019, 12:20:10 PM
Thanks guys.

The construction of the extension (lhs 1/3rd of house) is brick outside finish, so presumably cavity wall, but an inspection will be needed to see if it's insulated. the rest of the house has a roughcast finish so uncertain.

Personally, I thought EWI would be a good idea, but it's an awful lot of surface area, so costs might be too high, hence the IWI compromise as decorating is needed anyway. But, I need to read the surveyor's report as some (possibly a lot) of external work is needed, in which case that would be a time to consider EWI, I think.

I'm hoping to go with them next time they visit, but my sister has said floors are solid and sound when I suggested underfloor heating, but we will see.


Sorry this is so bitty, but I'm learning as i go along, and sharing on here, and using ideas, points and suggestions to raise questions for more feedback etc..

Thanks to all, again.


Title: Re: Advice needed on 'greening' an existing building
Post by: todthedog on October 03, 2019, 01:55:38 PM
 We used internal insulation to retain the look of the house (traditional Breton) also way way cheaper and I could do it DIY.
 CM did likewise different system easier to do if the walls are square.

Navitron share or used to the same address as Burley and the wood burners sold by Burley were rebadged by Navitron excellent fires worth a ring. Super efficient.

We found air/air ASHP really good. No rads.

We had concrete floor downstairs did not have the will to take it up for underfloor heating.
Ended up toasty and cheap to run.

On current Welsh pad CWI strongly  advised against by Building Research Establishment being in High penetrating rain environment .


Title: Re: Advice needed on 'greening' an existing building
Post by: M on October 04, 2019, 09:11:42 AM
More info.

Start off, completely forgot to mention, despite being asked (sorry), it looks like all windows need replacing, some old wooden, and old tired UPVC. My initial suggestion/guess to Sis was that the many, and large south facing windows should be good quality but DG, to benefit from the most solar gain as possible, but the smaller number (and size) of north windows might benefit from triple glazing. Anyone have any strong thoughts on this, DG v's TG, solar gain v's heat loss, and so on?

Having read the surveyors report, it seems the old structure is around 140yrs old and single skin, but all walls are in reasonable condition, not great, a few cracks that need attention, but certainly no major works that would help to justify EWI, so I'm thinking the IWI with redecorating is the best course of action. I used a plasterboard coated 80mm type in one room in my house when we stripped out the bay and found it was single skin. Great stuff. Any thickness recommendations, success with 50mm sounds good, but if there are no space issues, would it be best to go towards 100mm?

Tod, to avoid confusion (mine), contact Nav about wood burners, is that what you mean? They already fancied one or two, and when I explained heat pump may have limitations some years, and that a back up was a good idea, that seemed to cement the idea. Also they have a lot of trees, and apparently two or three dead ones to remove, so whilst a little concerned about longer term and age, I think they could be semi-sufficient if it's only as a part role in the house.

I shall interrogate Sis again on Sunday, and she welcomes help from the forum, and importantly is well aware that I'm simply the one-eyed man in the land of the blind, so learning as we go along.


Title: Re: Advice needed on 'greening' an existing building
Post by: brackwell on October 04, 2019, 10:27:54 AM
I agree with the N-S DG V TG viewpoint.

On the South facing, backalong i worked out the solar isolation for the month of JAN was almost equal to a good DG windows losses for JAN.  This was without the effect of curtains and assumed up to temp 24/7 .  My conclusion was that it did not justify the expense but then TG prices may have dropped and become amore available.

Are you still thinking you can get RHI on the HP?  I have grave doubts.

Ken


Title: Re: Advice needed on 'greening' an existing building
Post by: Moxi on October 04, 2019, 10:35:56 AM
Hi Mart,

Don't be too quick to rule out the EWI, there are a lot of DIY kits for it now and it really does have great benefits over the IWI.

as an example here's a link to a companies guide - I have no affiliation they were literally the first that had a good guide to look at - also Mods I cannot see that this is in conflict with our host but if I have erred then please remove the link and accept my apologies.

https://www.theecostore.co.uk/install-external-wall-insulation-system/

I cant do the posh links like others so maybe copy paste?

Moxi


Title: Re: Advice needed on 'greening' an existing building
Post by: Iain on October 04, 2019, 10:45:04 AM
Hi
I have a solid wall brick house. the external render was cracking. Went for EWI as it killed 2 birds with one stone.
If you do IWI and damp is still getting through you will have problems.
At least with EWI you get an external waterproof coat, the rooms don't loose any size, the structure of the building becomes a heat store, penetrating damp is eliminated and can really improve the looks of some external finishes.
Noticeable difference on my house. cooler in the summer, warmer in the winter.
Heating requirements have dropped dramatically.

Iain


Title: Re: Advice needed on 'greening' an existing building
Post by: Pile-o-stone on October 04, 2019, 10:50:59 AM

Personally, I thought EWI would be a good idea, but it's an awful lot of surface area, so costs might be too high, hence the IWI compromise as decorating is needed anyway. But, I need to read the surveyor's report as some (possibly a lot) of external work is needed, in which case that would be a time to consider EWI, I think.


Hey Mart :)

We're fitting IWI in our house because it's listed but I'd definitely have preferred EWI. I don't see the costs as being cheaper with IWI as it involves major works internally that are above and beyond normal decorating. You'd have to remove skirting boards, radiators, electrical sockets, floor boards, window reveals and sills, ceiling boards. Then you have to worry about dew points and whether the joist ends that go through the insulation will start to rot away. You have to ponder what to do with internal walls that connect to the outside walls, ideally you insulate these too.  You can spread the costs of all this work by doing it a room at a time, but that just means you're living in a building site for years and it costs more as you don't get bulk discounts for materials and tradesmen always seem to cost more when they come out to smaller jobs.


Title: Re: Advice needed on 'greening' an existing building
Post by: M on October 04, 2019, 03:21:46 PM
Again, thanks to all, I think my Sis is going to appreciate all the help and advice, and also rue the day she mentioned it to me, as she just wanted an easy life.  ;D

I don't know how much she can do, but she's in the perfect situation to do the best job possible if funds allow, and a few people have now mentioned converting the external walls into a thermal store (via EWI) which I completely agree with, especially if she does go down the route of a heat pump and needs to avoid peeks and troughs in energy demand.

Just today and yesterday I've been using the ASHP (A/C) to add warmth to the house, utilising some of ~1kW of PV generation in poor weather. If they were able to go with around 10kWp of south facing, then I'd suspect they'd be getting approx 4x the power I am, which is an awful lot of daytime semi-free heat.


Title: Re: Advice needed on 'greening' an existing building
Post by: todthedog on October 04, 2019, 03:34:24 PM
Wood burners ring navitron to see if they any contacts (do a deal type of contact) with Burley or do a deal themselves.

Wood burners do eat a lot of wood, which requires cutting, transporting, drying,stacking, restacking,storing , etc I reckon I was on first name terms with some logs prior to burning.
Our house was 150m2 and we burnt 9m3 a year.
 Mrs T said. dust levels have dropped since we no longer have a wood burner, but we have 1 dog not 3.

Double glazed in France, triple glazed in Sweden.  Triple glazed definitely better, for sound as well. Is there a huge difference in cost if installing a whole house.
-A mixture of the two if costs are tight. We have DG in Wales with no view  to  replace. Rarely hits -20c in Kidwelly facepalm


Both CM and I went 100mm insulation + pb.
EWI a no go as it would have changed the look of the house, DIY not an option at the time.









Title: Re: Advice needed on 'greening' an existing building
Post by: Countrypaul on October 04, 2019, 04:11:38 PM
With repsect to windows, I went with Tripple glazed on the north side and double on the others when we renovated this house. The tripple glazed is also darker than double glazed (which is darker than single glazed) but since our Tg face North and into trees about 10 metres away the lower transmission levels make little differnce. In our case there are two sets of bay windows on the north side, each about 3m wide and 1m deep, the glazed area being about 1.5m high so a significant amount of glass which I felt could also lead to significant cold air falling from the windows (we have UFH) and causing "draughts".

It was more expensive than double everywhere, but in the total scheme of things the cost difference seemed minor.

We have only been through one winter and it is difficult to tell how much difference it makes, but there is no condensation on the inside - we do frequently see condensation on the outside though.


Title: Re: Advice needed on 'greening' an existing building
Post by: pantsmachine on October 04, 2019, 06:15:51 PM
One of the biggest difference makers I found and it was late in the process was the search for air gaps. It made a huge difference to our comfortable environment. Got a clipboard out, assessed every room and sealed up all the weird and wonderful found. Instadifference. Doesn't cost much and enhances the inside/outside border hugely.


Title: Re: Advice needed on 'greening' an existing building
Post by: desperate on October 04, 2019, 07:28:56 PM
Hallo Mart, me again facepalm

Have you considered an entire rebuild? IE knock it down and start again to modern specs.  We are planning something similar and TBH refurbing the existing is soo bloomin expensive and nowhere near as good in the long run we may well demolish the existing building and recycle as much of the materials as poss.
Re-build costs come in at about 1200-1600/m2, food for thawt??

Desp


Title: Re: Advice needed on 'greening' an existing building
Post by: kristen on October 04, 2019, 07:47:57 PM
I've not been here for a while ... sorry, got a number of ideas, sorry for long diatribe that follows

I do not believe a solid house made from stone,concrete etc needs AC. The thermal mass makes a good job of stabalising temps.
We have Passive House extension,and all internal walls dense-block, so very little temperature fluctuation day-to-day and high thermal mass.

In the 2018 heat wave (went on for weeks) the temperature climbed to 25C (extternal was well over 30C day after day for a couple of weeks), that's quite uncomfortable to "just sit still" in. We used night-venting to cool, but in order to achieve that you have to be there, to open windows / security, so if we went away for a couple of days there would be no night-cooling. and we would gain a degree or two, which we then couldn't lose the following night. Lets the flies in too.

Personally, if I was putting UFH heating in, I would have reversible heat pump and cool in summer (when PV would be plentiful)

Including a complete new septic tank

We put anew digester thingie in when we were having major work done, on the grounds that the septic tank was old and might well fail in near future. We were able to re-pipe all downpipes, which just went to soakaways nearby (too nearby maybe??) to the old septic tank, and now use that as rainwater harvesting

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re-wire

did that too in the old part of the house. 4 x CAT5 to each room, and HA for the light switches. Seemed like a huge expensive luxury, but having now lived with it for a number of years very pleased to have done it. The main benefit was to reprogram the switches after we moved in and only then realised what we would actually want each switch to do. And we have added some "master switches" for things like all lights off when going to bed; and also all upstairs lights off at 10AM - I have no idea why visiting kids turn on a light in the morning, and leave it on, rather than open the curtains ...  also "pathway" switches to light all the way to kitchen (from upstairs; from the patio when coming in with an arm full of dishes after day turning to night on a balmy summer's evening, and so on. Alarm brings on all the lights in the house; "vacation mode" makes it look like we aren't away (ironically ..). Basically it just gives us flexibility over what the switches do. We haven't actually changed any circuits since a month or two after we moved in, but we changed lots in that period. We have at least half a dozen lighting circuits in the kitchen, individual dimmers for those would be an a nightmare to set each time, we just have 3 switches for 3 different "scenes" - Cooking (full blast!), Chill (subdues) and then Gentle (a coupe of steps down from Full Blast)

We also put in a whole house, plumbed-in, vacuum cleaner. We like that. "Bag" is in the garage, empty less than once a quarter, and all the "recirculated dust" that makes it through the filter of a conventional Hoover is confided to the "bag location"

Another suggestion: put a single isolating switch, with "neon light", for all the white goods in the utility room. These days they all use some parasitic power when "off", which annoys me even if 1W, but so many stories of fires, recalls, and even recalls-after-fixed ... I'm more comfortable with everything physically off when not in use / when we are away.

Alarm, including Fire Alarm (rather than a battery one that you might not hear ... our Fire Alarm sets off the Burglar Alarm sounder, no way of sleeping through them!)

CCTV?  Seems excessive, to me, but I would prefer that either the blighters do over someone else or, if they come in here, I have some nice piccies to give to Boys in Blue. We have both overt and Covert cameras, and in the sheds, and where yobs might come over the fence at the back and muck about smashing stuff.

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ceilings are simple no complicated architrave

We put in pukka plaster architraves in all the rooms after rewire/redecorate. Made a lovely improvement, and was one of the least-cost, best-feel-good, things we did

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Next we move on to PV. ... export, hopefully of 7,000 x 5p, £350, giving £800 pa

Battery and self-use, rather than export?

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They almost certainly will be moving to BEV(s) in the future, so additional benefits possible.

BEV has to be at home during the day to benefit ... Our primary BEV goes to work each day; we have debated having 2nd BEV and toggling them each day, so that "the other one" is at home charging from PV, and doing that instead of Battery (or instead of 2nd battery). Shifts £7,500 from battery-budget to 2nd-car budget

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Now for heating. ... ASHP could be good

My staring point for ASHP (or GSHP) is UFH, and thus hard floors throughout and no carpets.  Also very high levels of air tightness and insulation, so that the low temperature heating easily copes and the house is toasty warm for piddly-little amounts of energy.  Having, personally, gone for "zero energy" I now advise "Go for max comfort, but still tiny amounts of energy" instead.

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one or two wood burners anyway, but which are not planned for heating the house, just top up

We use, solely, the Wood Burner Stove at the shoulder Autumn/Spring ends, instead of boiler. House well insulated, MVHR moves the heat around, and the "fire" is a very cheering sight.

Our Wood Burning Stove is Passive House certified - it has its own external air supply, so as not to compromise the air tightness layer (by Building Regs requiring a wide open air-brick in the room!)

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some rads are doubles, but closer look needed ...

With Heat Pump if you don't go UFH then likely to need much bigger RADs (for lower temperature CH water). If you insulate much better then original sized RADs may well turn out to be right-sized

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So where am I going wrong? What am I missing?

As others have said, I too would aim for "no heat" rather than "not much heat". I would still install heating, in order to be comfortable. But well insulated, air tight, the heating requirement is tiny (Passive House has design requirement for peak heating to not exceed 10W / sq.m., so a one-bar-fire would be sufficient for an average 3 bedroom house :) )

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she would like a WT

I've considered that, each time I raise it on this forum the general advice has been that amateur sized ones are relatively high commitment, and I don't really want that sort of solution. PV, by comparison, is install-and-forget (but the wind blows during the dark of course ...).  Solar Thermal IME is high-maintenance, but subjectively from posts here I would say that for 50% of people it is zero maintenance, and the other 50% is more maintenance than makes economic sense.  I would NOT bother with Solar Thermal again, I would install extra PV and convert that into hot water only when I wanted it, and use the extra PV juice for something else the rest of the time.

Personally, I thought EWI would be a good idea, but it's an awful lot of surface area, so costs might be too high

I'm in the EWI camp too. The real gains come when you have good insulation, air tight, and zero cold bridging.

If your external brickwork is beautiful its a difficult decision. If not then cheapest is bang the insulation onto the outside of the walls and render over that.  The insulation join at the top, "under" the roof eaves and joined to the loft insulation, is the tricky bit - kinda "jack up the roof, put the insulation in, and lower the roof back again"!

Cold bridging becomes exponentially more problematical as the rest of the building is improved. If it gets to the point where it starts rotting things its very expensive to sort out.

If it causes convection draughts it wrecks the whole "comfort" benefit (Passive House wants window inside surface to be no more than 4C colder than air, in order NOT to get falling air / convection / draught / turn up thermostat / exacerbate!)

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hence the IWI compromise

Get a Passive House consultant in and see what they say.  I reckon the money, spent on the advice, will rule out (or in) some choices, and focus your mind on things that have a more certain outcome.

IWI steals all your, internal, thermal mass, so you can't "store" solar energy from the sun when it is helping in Autumn, Winter and Spring, and you are back to "lumpy" temperature swings.

many, and large south facing windows

You need to keep the sun off them in Summer, but encourage it in during Winter - eg. with overhang.

Helpful to also keep the sun off the West facing windows too - deciduous trees some distance away are ideal.  East side too, but sun / air temperature cooler in mornings, so of the three I think that least important to protect.

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the smaller number (and size) of north windows might benefit from triple glazing

Triple glaze the lot. Price differential DG / TG unlikely to be significant Pay attention to the frames and avoid and cold bridging etc. and make sure installation integrates with the insulation layer so that is "continuous". You need to be aiming for the inner surface to not get cold and induce convection, and therefore draughts; I doubt you can do that with DG.

We bricked up 50% of our North windows. They weren't really needed, and were hugely disproportionately cold. Those rooms , which were Arctic in Winter :(, are now snug. Of course if that is the only window in that room its not a good choice!

One of the biggest difference makers I found and it was late in the process was the search for air gaps.

We had air tightness test of the main house, before we ever thought about building a Passive House extension or major insulation initiatives. Also had Ivan round one freezing cold Winter evening, with his Thermal Camera, having had the heating on full blast all day. That was helpful to see heat-leakage (pleased to say we didn't have much).

We blocked up all the air leakage - amazing some of the places that blower-pressurisation smoke test found gaps to escape through ...

Have you considered an entire rebuild? IE knock it down and start again to modern specs.  We are planning something similar and TBH refurbing the existing is soo bloomin expensive and nowhere near as good in the long run

This is excellent advice. Wish we had new-built, rather than improving. And our outcome was that even with a relatively easy building to convert (1960, mostly "poured concrete") it was still far too difficult, so we built Passive House extension to hibernate in during Winter.

Knock down and Rebuild, to Passive House standards, will create a fantastically comfortable building, with the associated known additional health benefits, and capable of being heated on diddly squat of energy.


Title: Re: Advice needed on 'greening' an existing building
Post by: todthedog on October 05, 2019, 06:27:14 AM
I think the knock it down start again school has a lot in it's  favour .  Certainly  worth doing the sums. You get exactly what you want.


Title: Re: Advice needed on 'greening' an existing building
Post by: TT on October 07, 2019, 07:05:52 AM
Make sure there are underground ducts to any outbuildings from to where the location of the fuse board.

Same to where the boiler will be, it may allow you to pull in cables and pipework later without disrupting already finished areas.


You could live with the  oil boiler during the works until the insulation has been upgraded then install heat pump with a lower demand.

And wire up some cat 6 cabling in the house, helps with fixed appliances and helpful for additional Wi-fi access points


Title: Re: Advice needed on 'greening' an existing building
Post by: M on October 07, 2019, 12:55:52 PM
Hello again peeps.

Had another good chat with Sis. She was explaining that whilst they have access to the property, nobody will come out and look at anything (apart from the septic tank guys) until transfer is complete - which is fair, they don't want to waste their time.

I mentioned the knock it down suggestion, and it wasn't, shall we say, favourable. But it did raise a few chuckles. And as half of it is 140yrs old, Sis thought that would be a shame.

Regarding current boilers, whilst they are old and haven't run for a few years, the plan is to get them inspected and serviced if they are viable to get some heat this winter, otherwise, over to leccy heating (oil rads etc) and warm clothes. The two boilers and heating systems are separate, serving the old and new sections respectively, so, so long as one works, they can simply live in that part of the house.

EWi, whilst a bit scary, is certainly of a lot of interest. Sadly, the outside walls etc are in reasonable condition, so no killing of two birds, and part of the structure is very nice to look at, but certainly the possibility of doing some of the front/sides, and all of the back (north).

The property is licensed for caravans/motorhomes and has some power points in 'the field', so that's another big tick for PV, and 3-phase if possible. Plus Sis/BiL will be home most of the time, and also plan on getting an EV, so big PV and possible batt in future all getting ticks too.

Looking at the EPC, it's rated as needing up to 39k kWh's of heating, i assume that's based on a bad winter, as mine suggests 13k but we use around 6-7k kWh's of gas including DHW and oven.

Again sorry for the bitty nature of all this, and if things go well, should be able to give much better info in approx 3 weeks.


Title: Re: Advice needed on 'greening' an existing building
Post by: Countrypaul on October 07, 2019, 02:29:45 PM
Can you clarify the point about needing 39k kWh of heating, is that per day? or 39kW for the whole property when its -2C or something entirely different?


Title: Re: Advice needed on 'greening' an existing building
Post by: A.L. on October 07, 2019, 04:38:03 PM
hello,

Can you clarify the point about needing 39k kWh of heating, is that per day? or 39kW for the whole property when its -2C or something entirely different?

Probably 39000 kWh per annum.


Title: Re: Advice needed on 'greening' an existing building
Post by: Countrypaul on October 07, 2019, 08:05:10 PM
hello,

Can you clarify the point about needing 39k kWh of heating, is that per day? or 39kW for the whole property when its -2C or something entirely different?

Probably 39000 kWh per annum.

Yep, how did I miss the fact it was 39000 rather than just 39?  wackoold