Dazza Posted June 29, 2021 Author Share Posted June 29, 2021 1 hour ago, PeterW said: You will probably be on a mix of 28/22/15 depending on the routing etc. 4” sounds odd, sure it’s not a support column ..??! LOL! Actually I exaggerated - the flow and return pipes from the boiler are around 60-70mm OD, but when covered in lagging look much bigger! Link to comment Share on other sites More sharing options...
PeterW Posted June 29, 2021 Share Posted June 29, 2021 They will be 2” black iron - hence the monster flanged pump ..!! Link to comment Share on other sites More sharing options...
scottishjohn Posted June 29, 2021 Share Posted June 29, 2021 (edited) 11 minutes ago, Dazza said: external walls/internal walls floor etc? insulation value of a solid wall is by modern stds is so low as to consider as close to nothing gradually heats up in summer and sucks heat out in winter so either external insulation or internal required -as you say you are refurbing then internal seems simplest option new stud walls inside and insulation you can have house you can heat with a light bulb ,assuming you attend to any drafts at same time insulation you only buy once !! Edited June 29, 2021 by scottishjohn Link to comment Share on other sites More sharing options...
SteamyTea Posted June 29, 2021 Share Posted June 29, 2021 (edited) It is Thermal Conductivity Value you need to find. U Value is thickness and area specific. https://en.wikipedia.org/wiki/R-value_(insulation) This may be useful. https://www.engineeringtoolbox.com/heat-loss-transmission-d_748.html Edited June 29, 2021 by SteamyTea Link to comment Share on other sites More sharing options...
Nickfromwales Posted June 29, 2021 Share Posted June 29, 2021 For this property I would seriously consider a twin boiler setup to run them at reduced duty. They’ll be able to kick in in parallel to heat the place from cold, and idle accordingly when getting close / at target temps. Being reliant on one boiler for a large dwelling, and for both heating and DHW is a risk when it’s one large boiler. If you install two, you have 100% redundancy / aka fail-safe. Link to comment Share on other sites More sharing options...
Dazza Posted June 29, 2021 Author Share Posted June 29, 2021 Thanks for all the replies!! It has been really useful and productive to get others input! So, I have had a real rough look at approx energy loss and cost of internal insulation does definitely seem worthwhile! Just in case anyone is interested I approached it like this - the U value for my solid brick walls is probably somewhere around 2 W/m2.K - I have assumed this for the roof too as that is uninsulated. In my area I have figured the average annual temp is around 10C, so with an internal temp of 20C, give my walls a loss of 20W/m2= 175kWh/pa. Ignoring doors and windows, I have roughly calculated total area of external walls and roof is 655m2 So assuming gas is around 7p/kWh, annual cost would be £8146 for heat loss. If I insulated to U value of 0.3 this would come down to around 3W/m2.K loss per m2 = 26.28kWh/pa = approx £1205 pa cost for heat loss. So insulating to achieve 0.3 could reduce annual cost by around £6900!! On rough costings, I figured to insulate 655m2 using Kingspan K18 it would cost £14410, using 50mm Celotex and plasterboard over would cost £7,618, or using multifoil it would cost approx £6340. So it seems to me a pretty convincing argument that the insulation will pay for itself pretty quickly! Which brings me to my next question - the multifoil looks like the cheapest option and it is lot easier to work with than PIR boards, so was thinking of going down that route. Does anyone have any experience using multifoil for internal wall insulation?? As we have decided that internal insulation is the way to go (it will actually help with the refurb as well for ease of wiring etc) then once insulated, I think the boiler demands will not be anywhere as large so can get away with a single boiler. Link to comment Share on other sites More sharing options...
Mr Punter Posted June 29, 2021 Share Posted June 29, 2021 6 hours ago, Dazza said: we also got the in ground tank tank supplied and fitted FOC! A bit like buying a printer cheap and getting shafted on the toner. LPG is massively expensive. We once had LPG and it was cheaper to switch the heating off and go out to the pub. 1 1 Link to comment Share on other sites More sharing options...
PeterW Posted June 29, 2021 Share Posted June 29, 2021 1 minute ago, Dazza said: multifoil looks like the cheapest option and it is lot easier to work with than PIR boards, so was thinking of going down that route. Does anyone have any experience using multifoil for internal wall insulation?? Run. Away. Now. It doesn’t work. It needs to be detailed very carefully as otherwise it’s a foil tent. You’ll need double battens and board too - bet you find insulated plasterboard is as cheap in volume from CCF and easier to install. Go look at Seconds & Co, see what they have and work from there. Bonding PIR to solid walls is a no brainer too. Link to comment Share on other sites More sharing options...
Dazza Posted June 29, 2021 Author Share Posted June 29, 2021 Just now, Mr Punter said: A bit like buying a printer cheap and getting shafted on the toner. LPG is massively expensive. We once had LPG and it was cheaper to switch the heating off and go out to the pub. Yes LPG is more expensive but cleaner and can be hidden away - we went with LPG with our eyes open because it suited our needs better. I think it is also getting more competitive - we are with flogas and is £0.40 per litre + VAT and contract was only 2 years - we also took out the contract about 1 year ago and only just got around to installing the tank and getting filled, so will last us until we are out of contract anyway! Link to comment Share on other sites More sharing options...
Dazza Posted June 29, 2021 Author Share Posted June 29, 2021 5 minutes ago, PeterW said: Run. Away. Now. It doesn’t work. It needs to be detailed very carefully as otherwise it’s a foil tent. You’ll need double battens and board too - bet you find insulated plasterboard is as cheap in volume from CCF and easier to install. Go look at Seconds & Co, see what they have and work from there. Bonding PIR to solid walls is a no brainer too. Thanks for the reply - I take it you have experience with the multifoil? Surely it must work or wouldnt pass building control?? Looking at Kingspan they specified fitting the insulation on 25mm battens too rather than direct bonding to wall, so it seemed to me that was the best option and also gave a service void which is very useful. Excuse my ignorance, but who is CCF? Link to comment Share on other sites More sharing options...
Carrerahill Posted June 29, 2021 Share Posted June 29, 2021 1 hour ago, Dazza said: Excuse my ignorance, but who is CCF? Insulation/plasterboard supplier - do other building materials too. Link to comment Share on other sites More sharing options...
PeterW Posted June 29, 2021 Share Posted June 29, 2021 1 hour ago, Dazza said: Looking at Kingspan they specified fitting the insulation on 25mm battens too rather than direct bonding to wall, so it seemed to me that was the best option and also gave a service void which is very useful. Not sure that’s entirely correct unless you’re talking insulation and then board ..? If you go with insulated PB then it’s dot and dab back to the wall or mechanically fixed. Link to comment Share on other sites More sharing options...
SteamyTea Posted June 29, 2021 Share Posted June 29, 2021 2 hours ago, Dazza said: £8146 for heat loss. How does that compare to what you are currently paying? 2 hours ago, Dazza said: multifoil 1 hour ago, PeterW said: Run. Away. Now Too true. The testing method was completely different. The manufactures set there own methodology and it was rejected. Just remember, you cannot fool nature. Link to comment Share on other sites More sharing options...
Dazza Posted June 29, 2021 Author Share Posted June 29, 2021 14 minutes ago, SteamyTea said: How does that compare to what you are currently paying? It is an awful lot more (about double) and I am sure it is overcooked so to speak, but it does demonstrate that the insulation will get payback pretty quick - if not 1 year then 2 years. Link to comment Share on other sites More sharing options...
Dazza Posted June 29, 2021 Author Share Posted June 29, 2021 16 minutes ago, SteamyTea said: Too true. The testing method was completely different. The manufactures set there own methodology and it was rejected. Just remember, you cannot fool nature. Well, I would be foolish to ignore everyones advise, so I will stay away from multifoil! Actually the celotex with plastboard over was not that much more expensive and is tried and proven. Of course if I could get insulated plasterboard at a good price, then that of course is the easiest option. Link to comment Share on other sites More sharing options...
Mr Punter Posted June 29, 2021 Share Posted June 29, 2021 I like 2 x 1 battens fixed with long screws and plugs through 60mm PIR insulation. Finish with 15mm plasterboard. Gives a service void for cables pipes and sockets. Either foil tape the joins or cover with polythene. 1 Link to comment Share on other sites More sharing options...
Conor Posted June 29, 2021 Share Posted June 29, 2021 It's not just about "payback", it's about day to day comfort (not having big swings in temperature, needing the heating less), and well, shoving less CO2 it to our already screwed climate! 1 Link to comment Share on other sites More sharing options...
Nickfromwales Posted June 29, 2021 Share Posted June 29, 2021 1 hour ago, Mr Punter said: I like 2 x 1 battens fixed with long screws and plugs through 60mm PIR insulation. Finish with 15mm plasterboard. Gives a service void for cables pipes and sockets. Either foil tape the joins or cover with polythene. Just remember that all the penetrations ( sockets etc ) need to be detailed accordingly eg foamed behind to stop air movement ( draughts ). 1 Link to comment Share on other sites More sharing options...
Dazza Posted June 29, 2021 Author Share Posted June 29, 2021 Thanks again guys, you have been most helpful! Link to comment Share on other sites More sharing options...
Nickfromwales Posted June 29, 2021 Share Posted June 29, 2021 (edited) Do a plan for routes for new CH pipework throughout, and hide it in the voids. Continuous runs of Hepworth aka Hep2o insulated with 25mm wall Climaflex pipe insulation will bend around corners and weave in / out of studwork / other obstacles. Far reaches can be in 15mm ( servicing 5 radiators max ) and then it needs to jump up to 22mm. Several 22mm runs can be spurred off 28mm primary flow and returns but it needs a bit of thought / planning. 2 "system" boilers would ( can ) feed into a low loss header, pumped by their internal factory fitted pumps, and from the low loss header you simply pump away to the 28mm primary's. You can also have the low loss header with multiple 1" pairs of outputs which could have a domestic pump on each set of 22mm primary's. As said, it depends on the design and layout and how convoluted the pipe runs would be. Edited June 29, 2021 by Nickfromwales 1 Link to comment Share on other sites More sharing options...
TonyT Posted June 29, 2021 Share Posted June 29, 2021 7p for gas is a bit steep, you could half that cost by shopping about! Link to comment Share on other sites More sharing options...
SteamyTea Posted June 29, 2021 Share Posted June 29, 2021 2 hours ago, TonyT said: 7p for gas is a bit steep, you could half that cost by shopping about! That is for LPG, not natural gas. Link to comment Share on other sites More sharing options...
Dazza Posted June 30, 2021 Author Share Posted June 30, 2021 Thanks again guys. Yes, I def need to draw out a plan for runs! So it is definite that I need a system boiler with hot water cylinder - think someone suggested a 400 litre unvented or thereabouts (as well as kitchen etc will have 4 ensuite bedrrooms with showers)? Sorry if this sounds like a silly question, but how do you maintain pressure if all 4 showers were running at the same time? Also, the location where water tank would go is a bit limited in head height so I cannot have a "tall" tank - does anyone have any recommendations for tanks to suit (preferably pre plumbed to make life easier for me!). Also, is there a general consensus of a good brand boiler to go for or is that one of those where everyone has a different opinion? I did get a recommendation form an online boiler supplier for a Viessman boiler - any thoughts? Link to comment Share on other sites More sharing options...
SteamyTea Posted June 30, 2021 Share Posted June 30, 2021 (edited) 6 hours ago, Dazza said: but how do you maintain pressure if all 4 showers were running at the same time You may struggle with that. If you cannot get water into the system fast enough, there is no way it can come out fast enough. Try calculating at 10 litre per minute for each shower. One way may be to use two cylinders, of a vented and pumped system. You may be able to use plate heat exchangers as well, they can have a reasonable flow rate and power rating. Edited June 30, 2021 by SteamyTea Link to comment Share on other sites More sharing options...
TonyT Posted June 30, 2021 Share Posted June 30, 2021 20 hours ago, SteamyTea said: That is for LPG, not natural gas. Didn’t spot that, thanks! Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now