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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.

@chriz1 , Hello and welcome, here is a selection - https://novia.co.uk/breather-membranes

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

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.

@DerbyLad, The flat roof skylight? (Lantern) at 5.06m2 and U=2.7 would have a significant effect if U could be reduced to 1.5, about half the effect of reducing the wall from U=0.25 to 0.15. Also why is door 3 (D3) U=3.0, reducing to same as other doors would be about 1/4 the effect of reducing wall U value. Judicially reducing the design air infiltration rate would also help, but not to 3.0 or less which wood require a ventilation system, but you would have to achieve it come the 'as built' SAP assessment.

Hello and welcome. As long as the original house remains at normal levels of humidity and the cinema has frost protection levels of temperature then no VCL between them is required.

As long as this layer remains effective the wall will work but without it interstitial condensation will occur. Personally I would not want to depend on it. Putting the Phenolic board inside he Rockwool and moving the OSB to the inside of the studs would be the easiest solution

1) PH uses external dimensions, so if your house is a regular detached house with 90m2 of internal floor area per floor it is likely to have a footprint of around 105m2 which implies a maximum generation of 6300kWh per year which is easily achievable with 7.5kW of PV. 2) This for a PH+ house with the maximum energy use allowed (PER of 45kWh/m2 /yr). IIRC if it has a lower value the energy generated can be proportionately reduced. 3) There are panels in the U.K. for 30p per Watt e.g. https://midsummerwholesale.co.uk/

@CKelly, your build-up is potentially troublesome in the way described, foil faced Xtratherm is an effective vapour barrier 1) is the internal airtight membrane also a vapour barrier 2) how thick is the rockwool 3) is the foil on the warm side of the Xtratherm 4) is the watertight membrane water vapour open but liquid water proof

Not necessarily, an output of 12.5kW at a C.O.P. of 4.6 implies an electrical input of 12.5/4.6 = 2.72kW. The remaining 0.28kW could be for things they do not include in the C.O.P. calculation (often pumps etc)

@Roz 1) Your fabric heatloss is 95W/K and your ventilation heat loss 62W/K (in January) so a total of 152W/K 2) With a 22°C difference outside to inside then your total heat requirement is 22*152 = 3344Watts 3) It would be usual to oversize the boiler by 15% giving 3344*1.15 = 3846Watts and add 3000watts for DHW giving a boiler size of 6344Watts 4) Casual gains are estimated at 483Watts but probably safer not to subtract these. I would say from these figures a 5kW heat source is to small.

IIRC Passivhaus Plus uses footprint (not floor area) to calculate energy generation requirement. So a 100m2 footprint would require 6000kWh/annum. Even in sunny Edinburgh that is only 7-8kWp. You would probably only fit an inverter of 6kW anyway. The greater part load efficiency more than makes up for the slight loss on rare perfect days. Inverters which limit export are now available. If you could arrange for the panels to have two orientations this would further limit peak output. If your requirement is considerably larger then 3-phase, when 11.04kW can be exported without concern might be an option. You might find this discussion informative - https://www.navitron.org.uk/forum/index.php?topic=29370.0

Hello, if your current build-up meets building regs then you have a decision to make. Reducing the width of the service cavity reduces its contribution to the overall thermal resistance of the whole but this would be greatly outweighed by adding 12mm of PIR. Given the details that you have provided there could be a reduction in U-value of around 0.05W/m2.K which equates to an energy saving of around 2.5kWh/m2.yr. (Central England/Full SAP)

I would have to partly disagree, while longer decrement delay will reduce the percentage of the energy arriving at the outside getting through to the occupied space (the decrement factor) it would be better if the heat wave did not arrive at a time when overheating caused by other sources could occur. I disagree, I have been in too many overheating lightweight sloping ceilinged warm roof constructions. 11m OSB and 12mm Plasterboard both have Thermal Capacities close to 0.0025kWh/°C per m2 .

I believe @SteamyTea that the OP is referring to the time taken for energy arriving at the external surface of an opaque building element to transfer (in a temperature wave) to the internal surface and the room. @davidc, There is probably very little difference in 12 and 14 hours. I would be interested in your build-up and like Nick which software/method have you used?

@SuperJohnG, is this any help? - Small Building Structural Guidance (1.C.6) - https://www.gov.scot/binaries/content/documents/govscot/publications/advice-and-guidance/2020/02/the-small-buildings-structural-guidance/documents/small-buildings-structural-guidance/small-buildings-structural-guidance/govscot%3Adocument/Small%2BBuildings%2BStructural%2BGuidance%2B%2B.pdf

@Boris If your house is measured at less than or equal to 3.0m3/m2/hr it requires a formal ventilation system. If several similar houses have been measured you can assume 10m3/m2/hr, if single self-build 15m3/m2/hr has to be used. The principle effect of assuming a value is to increase the energy used by the house which increases the Dwelling Emission Rate which has to be less than the Target Emission Rate.

@Conor Take a look at 'brine earth heat exchangers' as an alternative https://www.sole-ewt.de/PDF/en/Sole-EWT-Info-en.pdf

The worst scuffing on the tower blocks seems to correspond with possible thermal bridges and little around boiler vents (warm-spots).

@Russell griffiths @nod ToughButterCup last posted on Mon this week https://forum.buildhub.org.uk/topic/15908-new-here/?tab=comments#comment-259990

@nod Has he not just changed his name (now Toughbuttercup)? He has done it before. From something to do with Newts if I remember correctly.

@tanneja , solid wall insulation (EWI) will be included according to the Department for Busines..... Look for 'Solid wall'

There are two versions, 1) Two thirds of an approved installation up to a subsidy of £5000 for anyone in England. 2) All of approved installation up to £10000 for qualifying low income home in England But there are some complicating conditions https://hoa.org.uk/2020/07/green-homes-grant/

I vote NO. Leaves are green because they absorb blue and red light and reflect green. The green is absorbed (along with any red) by the blue lenses so (relatively) no light (black) gets through making the leaves darker and more similar to the fruit

As long as the air barrier layer is correctly water vapour permeable the air barrier could be anywhere in the wall cross section. The outside of the inner leaf could be coated with a brush/spray on air barrier as the wall was constructed. The only issue would be penetration by the wall ties, https://www.blowerproof.co.uk/ https://www.intelligentmembranes.co.uk/product/airtight-white-brush/