Dan F

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About Dan F

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    Wokingham, Berkshire

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  1. I meant between exoperm and battens/slates. I can't see how partial boarding woule have an impact.
  2. You should be good then (without any air vents) as that membrane is vapour permeable and natural slates alllow ventilation of batton zone, even if you dont have a dry ridge systen with ventilation. As long as you haven't put anything vapor impermeable on top of expoperm (?). Agree with @TonyT, its likely temporary.
  3. £7k is with unitower. 2k for a UVC is a lot though, especially if its only 180L.
  4. It drops off yes, but it's not massive. SCOP at 55C (3.4). is only 22% less that SCOP at 35C (4.4). I agree heating with standard radiators at 75C isn't a geeat idea. The SCOP for 65/75C isn't published. The COP for A7/W65 is 2.8, but if I understand correctly, that'll be fair bit worse when it's colder outside which is when you need the heating!
  5. Are they natural or man-made slate? Do you remember what membrane was used below batterns on pitched roof? Was it this one? https://www.partel.co.uk/product/23/1/exoperm-mono-150-breathable-monolithic-membrane
  6. If it's MBC, they used this membrane on our build, just a couple of months ago: https://www.partel.co.uk/product/25/1/izoperm-plus-pha-vapour-control-membrane Is the roof-space vented?
  7. Why would you use a UniTower and not spec your own UVC, though? The temperature isn't limited, rather they don't actively promote it for >55C as COP above this isn't great and I think there is also something about RHI needing a COP >2.5. While you could theoretically use this for retrofit with standard radiators, I'm not sure thats a good idea personally. Yes, if you have the space. We have one on order. We'll unlikely ever use 75C flow, but who knows.. if we are expecting guests we could potentially temporarily increase the temperature from 55 -> 70C to increase the effective capacity of the 305L UVC from 460L to 610L. The main reason to choose this model was efficiency, minimal noise and low global warming impact. There are a number of manfuacters that do the newer R32 models that are all pretty good, some of which go up to 65C. Be careful though, because these maximum temperatures are only supported when the external air temperature is within a certain range as @ProDave also pointed out.. At -15C, it can still do 60C DHW, which is pretty good. By comparison the new R32 ecodan can't do more than 50C DHW at that temperature and the LG Therm V R32 maximum is 55C .
  8. @Adsibob Sorry, I confused you with my numbers! That 84% I quoted was as compared to Planitherm XN glass (which has light transmittence of 81% and solar factor of 0.6). If you look at the actual figures, the guardian solar glass actually seems to be marginally better than the Saint Gobain. See: https://www.saint-gobain-glass.com/products/cool-lite-skn The glass will be slightly tinted as a result of the coating yes, but that's rather different to a "tinted glass" which has been tinted deliberately to achieve a colour, like the ones in the document you attached previously. The web page gives you an idea of what it might look like externally and internally: https://www.guardianglass.com/gb/en/products/brands/sunguard/super-neutral/70-35 It's hard to compare the u-values as each manufactuer uses different thicknesses of glass/argon in their calculations, I woulnd't expext any significnat differences though. Not sure on the specifics, but I'd hazard a guess that guardian are probably number #2 in europe size-wise and as good as Saint Gobain. @craig would know... Didn't look at CRI when we chose glass, so not sure there, but it may be more important for solar control glass I guess, which we didn't use. Saint Gobain don't seem to uote this though, so can't compare. Obviously 98 is better than 94, but you can't get the reduced solar gain with no any other impact. End of the day, if you need the solar glass you get it, if you don't then you use climaguard which will mean i) no tint, ii) marginally better colours iii) more solar gain (beneficial in in winter, potentially issue in summer)
  9. Good point, need to watch out for that. Hot/cold routes are different as hot is fully radial and cold isn't, but will look out for this under sinks and add lagging if they get close. The argument for not needing to lag the 12mm hot runs was because they only have 300-350ml hot water in them which means: - Only 3-4 seconds to get hot water from tank. - Only 14Wh of energy lost to the house as pipe cools from 55C to 21C, which is nothing and certainly not going to contribute to overheating Good point. Was already planning to lag a 20mm MLP cold to kitchen unit run. Will add some insulation to 15mm branch to sink too, especially as the budget will probably run out before we get a chance to look at a fancy fridge or cooling/sparking tap thingie. A house we went to visit prior to starting on our self-build (not someone on forum) I remember them having to wait 10/15+ seconds for the cold kitchen tap to run cool to being able to serve us a glass of water.. Thanks!
  10. Today I asked plumber to: 1) Not bother lagging most 12mm MLP hot/cold. 2) To lag (in same insulation) the 12mm flow/return for 3 basins with radial recirculation as @Nickfromwales suggests) 3) Lag all other hot runs (kitchen sink, showers, bath), even though there is no recirculation. 4) Only lag cold pipes where they are: - Copper (in plant room) - 20/26mm MLP (used between plant room and satellite cold manfolds) Sensible approach? Sufficient?
  11. Yes, but only marginally due to the intial heat-up time. The main thing is that a 30-50% saving is worth a lot more (in monetary terms) the more you shower. An instantaneous WWHRS doesn't need to be close to cyclinder. Not seen this one, any idea how it differs to showersave/recoup? Is it not instantaneous and therefore more bath-compatible? Interesting!
  12. Depends on if you shower, how long you shower for, how long you plan to live in the house and how much you pay for your DHW. For us 30+ % reduction in costs of heating hot water (as well as 30% more effective UVC capacity for showers) is very much worth the £450 this unit cost, given we plan to live in the house long-term. For others, may make less/no sense... How does this work?
  13. What do you meant paying for points? It will also save you a lot of gas (assuming you shower rather than use bath)! Showers don't actually need to be close to the hot water tank. You can use them in "system B" where the WWHRS just pre-heats the cold feed to the shower. It's not quite as effiecient, but still saves a fair bit and will give you almost as many SAP points.
  14. Do a quick search and you'll find lots of views 🙂
  15. We were thinking of installing a bioethanol fire, more for effect more than for heat though. They aren't at all cheap though (at least not brands i've seen) and don't look that great either. Wondering if a Dimpex Opti-myst fire might better idea. It's water-vapour rather than flames, but they still look better than bioethanal, and you don't need to worry about them emitting even a small amount of heat..