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A_L last won the day on October 12 2017

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  1. Cost of eps is less for same thermal resistance, eps is unaffected by permanently damp environments, more eps may mean less of something else e.g. hardcore, eps can be obtained in load bearing forms up to at least 500kPa (10%) KayMetzler EPS.pdf
  2. Ideally should at least be covered to keep rain off. Under permanently damp conditions PIR can undergo hydrolysis (breakdown into constituent parts). It is why when used as under slab insulation it has a dpm below as well as above. http://blog.celotex.co.uk/technical/what-celotex-insulation-can-be-used-in-floor-applications/
  3. @Oz07 as http://forum.buildhub.org.uk/topic/10204-would-you-notice-much-difference-020-versus-017-u-value/?tab=comments#comment-172917 so about 1.2kWh/m2 per year
  4. @moldy, you are going to need something like 250mm of PIR/PUR in a timber frame with 50mm eps insulation on the outside and ewi render directly applied (no cavity)
  5. In central England (Midlands) SAP says it saves about 1.7kwH/yr per m2.
  6. Assuming buildings regs levels of insulation and reasonable levels of air leakage and no MVHR 8kW should be sufficient.
  7. Storage radiators charge at only one rate from the start of the charge period till the core reaches the temperature corresponding to the input control setting. They then passively give off heat till the start of the next charge period Perhaps this will help:
  8. When the storage rad is energised the resistor heats and the heat transfers to the bi-metallic strip which 'flexes' because the two metals expand at different rates, the bi-metallic strip will be attached to the flap and the flexing causes the flap to close.
  9. The thermostat which operates the flap is the metal strip, it is purely mechanical, it does not switch electricity. There is no room thermostat on a storage radiator. If you turn the output control while looking through the upper air grill you should see the damper open/close (or hear it) Leave the damper in an open position and wait for the next off peak period to see if it closes automatically.(have the input control set to a small value). The storage rads are on a circuit which is only energised during an off-peak period, there will either be a electricity meter capable of controlling this or a on very old systems a separate time clock near the meter. The off-peak rate is more expensive w.r.t. to on-peak now than it used to be and I expect it to decline in advantage over time.
  10. The flap should close automatically at the start of a charge period. If it did not you would simply be trying to fill a 'bucket with a hole in it'. The core would either never reach the temperature corresponding to the setting on the input control or it would take much more energy to do so and it would discharge continuously at a high rate. So the core would be cooler than expected at the end of the charge period.
  11. 12kW seems a lot for a newbuild. What floor area/insulation/air leakage? Nibe is at the expensive end of things so price for heat pump seems O.K. What sort of floor for the UFH and who is laying it? You will be paying for an 'RHI premium'. Most people on here get heat pump etc from ebay etc for a fraction of NIBE prices and forego the small RHI income on a well insulated house.
  12. A_L

    T stud

    @Ferdinand , you would be better using 6 rather than 5 as the correct value is 5.678.
  13. @steve77r, 'Fastwall' a slightly different approach which can be used on lightweight frames and done by you https://www.ibstockbrick.co.uk/wp-content/uploads/2015/08/04-06-Fastwall.pdf
  14. @gwebstech , for floors you cannot just invert the R value to obtain the U value, you must also have the exposed perimeter and the total areas as thermal resistance of a uniform floor varies with distance to the edge because you have to add in the thermal resistance of the soil
  15. Currently on BRE website https://www.bregroup.com/sap/sap10