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A_L last won the day on October 12 2017

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  1. I think they have to be interlinked but do not have to be mains powered? https://www.gov.scot/publications/fire-and-smoke-alarms-in-scottish-homes/
  2. If suitable at least check/get cavity wall insulation for all walls not to be 'internalised' by your extensions.
  3. Mineral gypsum has a density around 2900kg/m3, gypsum as in plasterboard/plaster has a density around 850-1000kg/m3. No, air permeability is a bulk process. Water vapour can escape by a process known as diffusion, this is a molecule by molecule process which bulk air cannot do. It is this process that vapour resistance values relate to. It is perfectly possible to have an airtight house which has little vapour resistance. Anything described as a 'breather membrane' should have a low vapour resistance while inhibiting the movement of bulk air. The cellulose does not get wet. The external air heats up as it moves into the wall by absorbing heat from it. This greatly increases its ability to carry water vapour (its relative humidity or RH is decreased). In warmer climates where the external air is warmer than the structure it can be a problem, but not in the UK.
  4. The effect on energy saving of thermal capacity more than 100mm from the internal environment is very small and generally ignored, it takes to long (>24hrs) for the heat to get in/out. Heating load is dependent on the rate of heat loss, i.e. a combination of fabric loss (U-values) and air infiltration rate (ach). The concrete would have to reduce one of these. Where walls are dominated by a single layer the wall temperature and the dew point temperature move in step as we go through the wall. As long as the vapour resistance of the external containing layers are not more than the vapour resistance of the internal layers there should not be a problem.
  5. @Hilldes you can fix UFH pipe to clip/mount rails which use adhesive patches to fix to any slipsheet/DPM without piercing it. https://underfloorparts.co.uk/product/underfloor-heating-clip-rail-track-1mtr-adhesive/
  6. @rbw Sorry, yes that's true, but it still has an outside box. I was really referring to 'air-conditioning' type splits. I know of one, quite small air conditioning, single room, no-outside box system that does DHW. https://www.olimpiasplendid.com/without-outdoor-unit/unico-boiler Usual health warnings apply
  7. @rbw split units generally have outside units, similar if a little smaller than monobloc types and they almost all do not do hot water. There are single room units which pipe air in and out and only have vents externally
  8. Leave the calyx on, store in a light cool place, no direct sunshine, with a ripe tomato. Once well dried you can move to a drawer. Do not refrigerate until at least orange in colour. Can ripen over six weeks or more. You can store beetroot in slightly damp (no suggestion even of liquid water on squeezing vigorously) used tomato bag soil until at least March in cold and dark but frost free conditions. Cut stems about 4cm above root (do not twist stems off), allow to dry a little before storing.
  9. Whichever side of layer 15 (12mm ply) would give fewer penetrations.
  10. @Tony C, The VCL could be placed in either position. The deciding factor might be the number of penetrations of the VCL and the method of fixing the Celotex. Properly installed the foil surfaces of the Celotex have a greater vapour resistance than polythene vapour barriers with the usual penetrations and taped joints. Section 7.3 and 7.5 here https://insulation-uk.com/assets/5405_dry-lining_bba-certificate_nov2018.pdf
  11. The SAP score is a cost index, higher values, B rather than C indicates a lower fuel cost. SAP uses a cost 0f 13.19p/Kwh for electricity and (where a value is not available on the PCDB, product characteristics database) a default COP of 1.7 for ASHP or a cost of 13.19/1.7 or 7.76p/Kwh. For gas SAP uses 3.48p/Kwh for gas and primary energy factor (a measure of the amount of gas to give 1Kwh of output) of 1.22 and therefore a cost of 3.48 x 1.22 or 4.12p/Kwh. Thus gas will give a higher SAP score than an ASHP.
  12. The foil facings have a water vapour resistance significantly higher (1000MN.s.g-1 ) than the value normally used for polythene vapour barriers (300MN.s.g-1 ). Section 7.3 and 7.5 here https://insulation-uk.com/assets/5405_dry-lining_bba-certificate_nov2018.pdf So you will unavoidably have a VB anyway.
  13. @chriz1 , Hello and welcome, here is a selection - https://novia.co.uk/breather-membranes
  14. PT100/1000 sensors on you know where can be extended with almost any wire https://www.navitron.org.uk/forum/index.php/topic,25254.msg291980.html#msg291980
  15. How about waste water heat recovery? (WWHR). Save about 50-60% on shower water energy and get you a few SAP points. https://recoupwwhrs.co.uk/products/ - others are available. East or West PV in Oban will produce about 670kWh/yr per kWp. How about 3kWp East and West? You will never see more than 4kW instantaneously and a standard 16A/Dual MPPT would handle it.