offthepiste

Thank you to all, 13/14 it is then, cheers

Hi @joe90 yes will be gluing down. Thank you

Have read through all posts that I can find related to my question. However, not found anything that exactly helps my head scratching. Also, wonder if anyone has had more experience with their own situation. We are about to select engineered oak wood flooring – planks @200m width +/- 10-20 to be fitted on out ground floor above a newly laid concrete floor with wet UFH taking into account humidity etc. Concrete floor will be well insulated along with reasonably airtight and insulated house done as part of our Enerphit’ish renovations. UFH will operate at “low”, temperature, e.g. average equal or just below 27 degrees, as per wood supplier advice and to optimise the ASHP. My dilemma is whether to go for 13/14mm or 20mm thick planks. The 13/14mm will only have top layer 3mm Oak and the 20mm will have 5mm. I will sort of feel safer with 5mm than 3mm in case of need to re-sand. However, there is just the two of us with no kids or animals and we are quite careful. Also, appreciate that 20mm will be more thermally insulating than 13/14mm but we plan to run heating almost 24/7. But 20mm costs more than13/14mm. Also, probably have a couple of large oriental rugs in front & rear living rooms but assuming that this will be OK. Any advice or experiences gratefully received, cheers to all.

Useful info ... looking to install Sunpower Maxeon 5 AC (fitted expanse micro inverters) in two separate strings on two separate flat roofs. Came across this reasonably current Sunpower 'Safety and Installation Instructions for AC modules' dated 2021which I assume may apply to UK installs. https://sunpower.maxeon.com/uk/sites/default/files/2021-06/Safety and Installation Instructions for AC Modules 537620 RevD Final.pdf Seems to have pretty clear advice on grounding / earthing. Only question I have is whether I need to ground with separate, say copper, cable to a grounding plate / pole buried in the earth or whether I am over thinking this. Advice gratefully accepted! Cheers to all

Still ruminating over how we should handle our kitchen extractor. Research suggests that overhead updraft is better than downdraft, so sort of decision made there. However, given how and what I tend to cook - a lot of fish on top on griddle / bring pan and also under grill - and what I have read about particulates from cooking ... would really like a proper extractor and not a recirculating unit. However, as everyone will know this is an issue with an airtight'ish house and need to balance output and input air supply. @Iceverge post re Naber got me looking their other products .. there is one which looks like it would work.. https://www.naber.de/en-bixo-balancer-waste-and-fresh-air-wall-conduct-s13823/ BUT ... how reliable will this be in the long term??? Either in maintaining the (I guess Bluetooth) pairing between the input & output vents and also the twisting of fabric to make it "airtight" when extractor not in use. I prefer to keep things simple .. so suspect, unless anyone has a brilliant suggestion .. to go for recirculating. In respect of recirculating extractors did a bit of searching regarding plasma filters and came across this https://www.plasmamadefilters.co.uk so was wondering if it would be possible to retain the normal washable grease filter and then belt and brace it with a plasma filter. I think there may be available extractor hoods which include plasmas but they may be a bit pricey. Also want to minimise grease etc in the MVHR units. Cheers

Hi @SteamyTea From what I can work out no shading issue, panels will be at about 155 degrees, and I overlaid a sun map https://www.gaisma.com over google map and also used https://findmyshadow.com where you can specify 3d shapes ... I was originally worried but looks like not an issue.

As we will need a new tumble drier have been looking at ones with heat pumps such as Miele TCR780WP rated at an average 174kWh per year

Hi @ProDave hah.... yes, I am a bit anal, and have scoured various white goods and other electrical devices specs as well as statistics and common sense to estimate both DWH and DE usage even spitting kWh required to heat water (estimate 12 degrees) to 55 or so degrees for dishwasher and washing machine and then estimating energy used for pumps etc, e.g. we have 2 Macbook pros always on charge, 2 iPad pros, as well as about 5 iPhones (!!!) and large screen etc which I have estimated at 357 kWh for 1 hour each a day 365 days. Have estimated direct electricity is 2,560 kWh / year and DWH is 6,028 kWh / year

@pdf27 & @BenP Hi, keen to retain our existing and relatively (25 year) new clay tiles (Victorian house). New dormer is partially for energy improvements but also a platform for potential Solar PV panels. If I was to go Solar PV I had been looking at the Sunpower Maxeon 3 400W which seem to be the most efficient on the market - however am going to hold off. Agree re MVHR - it will be a pleasure to have better air as well and also UFH at 35 deg. Highly likely will get an ASHP for UFH and possibly use for DWH at some time - using overnight cheap rates. Am working on assumption - having read various posts - that will run UFH during the day say for 15 hours rather than 24/7.

Hi @joth will be tackling the roof - complete rework and new dormers etc. basically ripping the insides and outsides out. Plan to pre position cabling or at least ducting & possibly thin ply fixings for Solar Pv and possibly battery cabling - the latter would go in the garden as I believe there is a yet to surface risk of domestic battery fires and want to keep it well away from house if ever I get around to one.

Hi @joe90 yes likewise on insulation and air tightness, working on 50kWh/m2 as Airtightness and having to have IWI will stop us going to full Enerphit without spending huge amount. Will probably such it and see how much electricity we are consuming after first year - hope to finish end 2022 - and then look at Solar PV again. Batteries look quite expensive.

Given imminent Enerphitish project have just been noodling over back of fag packet estimates for space heating (SH), direct hot water (DHW) and direct electricity (DE), e.g. sockets & lights, given assumed space heating requirements of 50kWh/m2 for 300m2 and various options from keeping existing Viessmann 222-f though ASHP for SH and possibly DHW as well as Solar PV @3,680 kWh projected output p.a. and battery such as Powerwall 2. Am a bit surprised by my conclusions … but working out electricity needs after estimating Solar PV generated and SH needs by calendar month it looks like Powerwall would take about 20 years to pay back and Solar PV about 7 years - assuming Octopus Go Faster tariffs and ignoring trivial opportunity to export back to grid, i.e. Tesla tariff. On the assumption we are heading back to the good old days of sustained inflation I could perhaps argue that capital investment now would reap benefits but then again there may be new innovations and I avoid extra complications by more things to go wrong. And willing to risk blackouts.. So am thinking of not having a battery (definite) or solar pv (probable). Any thoughts? Cheers

Agree re stick tape. Current thinking is to try to minimise use by leveraging plaster, either existing if appropriate or new to close gaps, etc. but obviously will need a different solution re joists and their holes (not sure if there is a technical term) etc. Am having a "little bit of a debate" at home regarding the need to avoid a letterbox!!!! I have found a few quite smart looking, i.e. not tweeeeee, standalone cabinets that take letter and possibly parcels. Do not want to fix to wall and thinking of semi hiding behind hedge ... we will have the educate the postman ... once the debate has subsided.. One attached to rear of front wall would have been ideal but our house is located just at the distance that local yuffs start to get rid of the remains of their trans (a word much in fashion these days )fat foodand packaging... a public facing letterbox would be toooo tempting.

Hi @joth I am erring on the safe side .. have been in discussions with a company that specialises in period property, e.g. georgian & victorian, retrofits. They originally aimed for true Enerphit but have leaned over many years that airtightness measures progressively, sometimes quite quickly, become undone within the fabric of an older building. Hence, whilst we may target 25kWh/m2 I am working on 45kWh/m2 for a potentially realistic view. It would be interesting to hear from experiences of those who have done this sort of thing. One of the challenges I have is a cellar which will be split into plant room and separate fine wine cellar (want to retain current 12 deg and humidity levels) there are lots of potential surface / material interfaces and dimension constraints and want to keep things simple primarily to be able to tolerate any insulation / airtightness deterioration as well as keeping costs down.

Brilliant, thank you all. So pretty much decided on ASHP for both SP and DWH along with Solar PV (potentially Sunpower 400W) and battery (potentially Powerwall) - this simplifies everything. Was starting to get into the long grass .. Just done some calculations comparing Octopus Tesla (will have insufficient to export) and Go Faster tariffs - this is not going to get implemented until August next year (fingers crossed) and heaven knows what will happen to rates etc. and think on current basis Go Faster, charging Tesla to max and using Solar PV to max during day, is the best option. Now need to decide on ASHP.(am very intrigued by the RED ASHP) and Heat Store .as well as MVHR . house will be 300m2 to an Enerphish standard ... I am guessing perhaps to achieve 45 kWh / m2. Amazingly in our very drafty mid terrace Victorian we currently only consume 30,000 kWh gas for 280m2, i.e. for both SH and DWH. So am guessing if 80% is SH, then we have a rating of 86kWh/m2 - though we do have a Viessmann 222-f and tend to layer ups in the winter like today - but there are only two of us and we only really use the ground and first floors.

Am starting to try to narrow down various ASHP options and their associated energy costs for space heating (SH) and direct hot water (DHW). However, I have one (of many) very large area on zero knowledge. I am trying to decide whether to run the ASHP at 35deg, i.e. just for SP, or at 55 deg for DWH. I spotted a thread which seems to address the issue but I want to make sure my understanding is OK. Question: If you run an ASHP at 55deg, achieving say at COP 2.5 - 3.0, how do you handle UFH at 55deg? This seems bonkers. So there seems to be two schools of thought: 1. ref @ProDave https://forum.buildhub.org.uk/topic/8265-temperature-of-hot-water-leaving-your-ashp/?do=findComment&comment=141288 who has the funky solution of running the ASHP at 37deg for a period of UFH (I guess during the day) and 55deg for DHW (I guess during early morning to heat up tank) – which means achieving two separate COPs. 2. Ref @newhome https://forum.buildhub.org.uk/topic/8265-temperature-of-hot-water-leaving-your-ashp/?do=findComment&comment=141342 who I guess runs at 55deg but blends the UFH with cold water and I guess only achieves the lower COP. 3. Are there any others? I would have assumed that ProDave solution is the best as you can optimise COP. Cheers

Ref the options I am considering... and just about to digest the paper @SteamyTea has provided... the other possible option is the direct electric heating route, e.g. willis heater or similar. Gut feel is that heating on demand with no standing / mixing water would be the most efficient especially is heated as close to the coal face as possible. However, I have seen comments, and from I can google, there is no solution which could fill a 100l bath in a sensible period of time. Again, ideally would like to leverage the 35deg ASHP water via a heat exchanger such as at the lowara https://docs.rs-online.com/a006/0900766b81610cf1.pdf. Cheers

Hi SteamyTea, thank you for this... will have a look. Cheers

@PeterW have been reading through the voluminous posts regarding TS vs UVC vs Sunamp in combination with an ASHP (at 35deg for max COP) and some Solar PV + Battery for Enerphitish project. Am leaning towards UVC or TS, though have noticed that Sunamp have just released their Thermino, though little info on this yet. Re UVC vs TS, my assumption both could take advantage of ASHP water at 35deg, UVC - this would require the equivalent of a TS (small, and I know perverse) purely to exchange heat from ASHP water to mains for supply to UVC which would then be boosted by Immersion(s). Unless, there are UVC that also have heat exchange capabilities? TS, such as Harlequin Heatstream would exchange ASHP 35deg to tank and then be boosted by an Immersion (the Harlequin spec includes an immersion). I am assuming that both 1. & 2. would produce the same result bar tank heat loss rating. However, would there be different stratification of water between 1 & 2 - cannot make my mind up about this. Have seen some manufacturers have different solutions, e.g. "nozzles" for injecting water into tank but this may just be hype. If ASHP 35deg (thereabouts) cannot be used as starting temp for either UVC or TS solution, then running an ASHP at 50 deg plus is cheaper re electricity capacity. Its a shame about the Sunamp but seems to risky from what I have read. My goal is partially driven by wanting to minimise my reliance on utilities given future prices and possible disruption and am prepared to spend my hard earned cash to do this ... though with hopefully a bit of common sense! Cheers

Hi Larry, thank you .. interesting comment about PVA .. starting next Feb but may try to get a "sample". Suspect that there its lots of lining paper covering up cracks etc. as well as old Victorian wallpaper. Think major works were done (on the cheap in the 70s's ) but suspect that surface may not have changed others than repainting over the decades with matt emulsion. Cheers

Hi Simon, Thank you for this information .. I have had my head in work .. will probably know more about build up next Feb when we should start in earnest. Cheers

Not sure if this topic thread is dead but .... a daft question. Definitely going to do IWI. Current state of plastered walls is sound. They are painted with emulsion ... probably Dulux .. possibly trade but maybe not. I would prefer to retain plaster as it provides largely good airtight barrier .. where any cracks or gaps etc can be resolved. It would feel perverse to hack it off and then either do a parge coat of lime plaster say, or worse stick that blue membrane I have seen in renovation photos. My gut feel is that sticky tape, however industrial, may not last. So if I retain and make good exisiting plaster then I suspect the emulsion is not breathable. My guess is then to steam and scrape off rather than replaster. Any advice, cheers, thank you in anticipation

mmm these days I am never sure ... world is upside down ... I think I am more of a determinist these days ... but then again probably not .... perhaps I will have to "string" this out....

... warning ... about to brag .... it was Werner Heisenberg who suggested I read theoretical physics (rather than philosophy & science) ... when I was (obviously) quite young and he was very old...

Brilliant