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westcoast

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  1. sorry, I don't understand this, I'm not looking to 'overcharge" my Sunamp. I plan to use primarily solar energy to heat the Sunamp. If its cloudy or short winter days I will use supplementry E7 electricity to complete the charge for the next day.
  2. No, solar array + E7 + Sunamp(or cylinder) for DHW This is what got me thinking about Sunamp in the first place - i could store E7 energy with minimal loss and inject when needed Hmm, this is another factor I hadnt really considered. ASHP would protect me more for future energy price-hikes 🤔
  3. Thing is, I believe the house will need very little space heating, prob a pulse in the morning and a pulse in evening for coldest winter months. Pay-back for ASHP could be quite long time. Wonder if direct electric heating (Willis or otherwise) would actually make sense in my situation. Do ASHP units mind being powered-off for 8-9 months of the year?
  4. So is the general consensus for best value still: heat pump + storage cylinder for space heating?
  5. Thanks Dave, fair enough, that does sound like the sensible option.. i might be a bit fixated on this technology! The risk of failure though I might be willing to take as the design is inherently simple e.g. no moving parts or corrosion to worry about. 10 year guarantee @ ~3000 euro. A recent look at the last page of the Sunamp megathread here looks like the mood seems to shifting in favour of the newer units.
  6. Thanks for the reply! Sunamp has about 4x better energy efficiency in terms of heat loss compared to cylinder, no maintenance, much smaller unit, simple install, no discharge pipework etc.. (3x the price though..) Maybe A2A is the way to go.. I've heard of lot of negativity about them in general. Will have to research further. Very interesting.. Another Sunamp powered by solar array + E7
  7. Hello again, Looking for some advice, any help would be appreciated! I am in process of building on west coast Ireland. I only have 170mm of floor space for insulation+screed due to a mistake with large sliding doors installation. No going back now. Prob have to go with a 40-50mm liquid screed and maximise my insulation. Building facts 2 bedroom house, wall U-value 0.15, roof 0.13 Special care is being taken for air-tightness (all Pro Clima stuff) high level of thermal mass (block-on-flat construction with 200mmEWI - no internal insulation) partition walls all block. Around windows and 1st and last course thermal block. Approx 100m2 of UFH space heating requirements Irish winters do not get that cold, just damp. rarely into negative numbers UFH will only be used for 3-4 months of the year Solid fuel stove for chilly nights. (Double insulated flue, dedicated air intake) I'd like to keep my heating system as simple as possible and Willis heaters have been suggested but as I am constrained to a thin screed my floor will not act as a storage heater (heat would be released too early if using E7). What do you think of these options?: 1. 9kwh Sunamp + E7 electricity, SA will provide the 'storage' element then just blend valve into UFH manifold, it would be an 'on demand' UFH system rather than a giant storage heater slab. 2. ASHP and buffer tank - requires an additional tank, more complex plumbing, maintenance costs, lifespan of ASHP, higher initial cost, noise. 3. another (expensive) option would be to get a Sunamp compatible with ASHP and start with only E7 use then purchase an ASHP later if running costs too high.. (heating requirements attached) Heat loss calculator - Ballycummin.xlsx
  8. Really interesting, thanks for that info, I need to accurately get a figure for my heating load. Will work on this over the week. For my 'good' Air-Tightness I am going to spend as much as budget allows, which means: - Intello membrane internally, bonded to scratch coat on walls - careful taping to window reveals, doors etc - Correct cable entry grommets used when membrane needs to be pierced - Chasings and below screed wall to be coated with sprayable liquid sealant Unfortunately the stove is an aesthetic decision and is 'non-negotiable', it is of decent quality though with triple insulated flue.
  9. You are right, sorry, I was assuming Kooltherm was just standard PIR insulation, I had looked at Kingspan a while back before we compromised and decided it would be our only option... The question is, how can I calculate the heat release time for different thicknesses of screed? .
  10. No chance to move floors: windows and doors are in. Large sliding patio door would catch on floor if raised. it was 150mm EPS originally planned, will check with our engineer, but 150eps and 100 pir roughly equivalent, no? Not spoken to BER assessor yet, but it could be a good time to get in touch!!
  11. Thanks for the detailed reply, I was getting a bit worried about 100mm being enough insulation (we had originally left 150mm but had to make compromises..) The online Kingspan calculator works out at 0.14 with 100mm insulation: https://www.uvalue-calculator.co.uk/calculator/floors/ground floor/solid concrete - insulation below screed/0.5/100/ I could possibly go to 110mm insulation (achieving 0.13) if using a 55mm liquid screed - I suppose this would only create a 13 ton storage heater! But there is an obvious trade-off here with: more thermal mass and slower release vs. less heat loss overall Thanks this is great and puts it in perspective.. I think I saw a spreadsheet on here somewhere to calculate ones heating load/requirements, I should really find that and try to make a more precise estimate. . The good thing for us is we have a small stove for heat NOW! ... but I take your point, its a careful balancing act, your demand cannot exceed the cost threshold making all the effort redundant. Having to use the Willis heaters throughout the day would be a fool's errand. That was brave move indeed, but I understand what its like to spend a lot of money on insulation. I want to gauge the performance of our house over a year or so before adding anything too fancy - hopefully the Willis heaters will be sufficient anyway. I suppose my main concern now is Screed thickness vs extra floor insulation, will a thinner screed make the Willis idea useless as the heat will escape shortly after off-peak hours.. ? Cheers
  12. Thanks for reply.. thats good advice re ufh pipes.. already 50% into build though so it will have to be PIR at this stage..
  13. very interesting, thanks for this, is that Irish code or UK I guess they are pretty similar anyway. Sounds like PIR is probably a safe bet
  14. Thanks for your replies Peter, we will have MVHR and the house is well insulated + lots of thermal mass (block-on-flat construction with 200ewi) didnt see the need for every room to be heated, also in my experience living in a house with UFH, it was never used in bedrooms and very rarely in living room.. Just been reading up on some of your knowledgeable posts about Willis heaters, one thing comes to mind: Most people seem to use Willis heaters to heat whole slab with E7, which would slow release throughout the day.. but we have insulation on slab and a 70mm screed. I wonder if the floor would still be warm in the morning? and would escaping heat just be trapped in our wall thermal mass anyway? btw our 70mm screed only gives us space for 100mm insulation below, will have to use high performance, maybe PIR? thanks again!
  15. Thanks a lot for reply. So rising main directly into Sunamp is sufficient? ..but without power showers I'm guessing I would need to increase pressure after heating?
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