Mike_scotland Posted March 10, 2021 Share Posted March 10, 2021 Can anyone help with insulation and u values? What is a good, middle of the road UValue for a new build house? In terms of walls, live in roof, flooring with UFH? Link to comment Share on other sites More sharing options...
Mr Punter Posted March 10, 2021 Share Posted March 10, 2021 These would be a start Link to comment Share on other sites More sharing options...
Buzz Posted March 10, 2021 Share Posted March 10, 2021 Price for the minimum and then keep adding 2k at a time until you hit a number your happy with , if its in budget happy days if not something's got to give , posh kitchen /weak sap , ikea kitchen/good sap . not quite that simple but you get my point . For new build homes, there are two levels for a designer to consider: Limiting Fabric Parameters: The minimum requirements for an individual building element. However if minimum standards were used throughout then the home would fail the overall TER (Target CO2 Emissions Rate). Concurrent Notional Dwelling Specification: A set of requirements for all building elements which together should meet the overall standard (the TER). Area Limiting Fabric Requirement W/(m2K) unless stated Concurrent Notional Dwelling Specification W/(m2K) unless stated Roof 0.2 0.13 Wall 0.3 0.18 Floor 0.25 0.13 Windows 2.0 1.4 Doors 2.0 1.0 – 1.4 depending on glazing Air permeability 10 m3/(h.m2) at 50 Pa 10 m3/(h.m2) at 50 Pa Link to comment Share on other sites More sharing options...
Mike_scotland Posted March 10, 2021 Author Share Posted March 10, 2021 I think the house is going to be 140mm Frametherm in external walls and 150mm wool between studs? So im assuming thats 290mm altogether for walls - no osea U VALUES yet. 100mm in slab then 50mm under ufh? So 150mm in floors. 150 PIR Insulation between rafters then 20 PIR Insulation over rafters 420mm in 2 layers over flat ceiling at F/F level Any thoughts? Link to comment Share on other sites More sharing options...
Mike_scotland Posted March 10, 2021 Author Share Posted March 10, 2021 We also want ASHP so wanting be insulated well or its a waste of time with an ASHP im told Link to comment Share on other sites More sharing options...
ProDave Posted March 10, 2021 Share Posted March 10, 2021 9 minutes ago, Mike_scotland said: We also want ASHP so wanting be insulated well or its a waste of time with an ASHP im told Air tightness is more important for making MVHR work, and that is more about getting detail right than costs. Link to comment Share on other sites More sharing options...
Mike_scotland Posted March 10, 2021 Author Share Posted March 10, 2021 6 minutes ago, ProDave said: Air tightness is more important for making MVHR work, and that is more about getting detail right than costs. Were not planning on MVHR? Did you mean ASHP? Or am i missing a trick with not having mhvr with a ashp Link to comment Share on other sites More sharing options...
ProDave Posted March 10, 2021 Share Posted March 10, 2021 3 minutes ago, Mike_scotland said: Were not planning on MVHR? Did you mean ASHP? Or am i missing a trick with not having mhvr with a ashp Sory brain freeze. Yes insulation particularly floor insulation to make ASHP and Under Floor heating work well. Link to comment Share on other sites More sharing options...
Mike_scotland Posted March 10, 2021 Author Share Posted March 10, 2021 What do you think is a good thickness? It will be pir and at the moment its 150mm Link to comment Share on other sites More sharing options...
Buzz Posted March 10, 2021 Share Posted March 10, 2021 Hi , @Mike_scotland U-value Calculator (uvalue-calculator.co.uk) Someone posted this before i found it very helpful, and easy to use . 150mm pir is passive standard. Link to comment Share on other sites More sharing options...
Mike_scotland Posted March 10, 2021 Author Share Posted March 10, 2021 13 minutes ago, Buzz said: Hi , @Mike_scotland U-value Calculator (uvalue-calculator.co.uk) Someone posted this before i found it very helpful, and easy to use . 150mm pir is passive standard. Thanks bud, the 150mm pir is the floor. Link to comment Share on other sites More sharing options...
Buzz Posted March 10, 2021 Share Posted March 10, 2021 (edited) 7 minutes ago, Mike_scotland said: Thanks bud, the 150mm pir is the floor. depending on the floor build up ( on block and beam ) 150 pir delivers 0.1 Edited March 10, 2021 by Buzz Link to comment Share on other sites More sharing options...
Mike_scotland Posted March 10, 2021 Author Share Posted March 10, 2021 It is concrete slab i believe 150mm thick. Link to comment Share on other sites More sharing options...
A_L Posted March 10, 2021 Share Posted March 10, 2021 2 hours ago, Mike_scotland said: I think the house is going to be 140mm Frametherm in external walls and 150mm wool between studs? So im assuming thats 290mm altogether for walls - no osea U VALUES yet. More construction details required but if this is 290mm of Frametherm 32 then worst case is better than U=0.15 2 hours ago, Mike_scotland said: 100mm in slab then 50mm under ufh? So 150mm in floors. with the details you gave yesterday U=0.11 but it really should be one layer either above or below the slab depending on the response time/storage capability you want 2 hours ago, Mike_scotland said: 150 PIR Insulation between rafters then 20 PIR Insulation over rafters U about 0.19, making the 20mm layer 75mm would give about 0.12 2 hours ago, Mike_scotland said: 420mm in 2 layers over flat ceiling at F/F level That,s about U=0.11 Link to comment Share on other sites More sharing options...
Mike_scotland Posted March 10, 2021 Author Share Posted March 10, 2021 Is it better having 150mm in the concrete slab? Rather than above? I think they need insulation above to clip the UFH piping too. Link to comment Share on other sites More sharing options...
A_L Posted March 10, 2021 Share Posted March 10, 2021 9 minutes ago, Mike_scotland said: Is it better having 150mm in the concrete slab? Rather than above? If you want to heat intermittently then it is probably better to have the insulation above the slab. If you want to heat 24/7 and perhaps try to use an off peak type tariff then insulation below the slab gives a greater storage capacity. There are other methods to fix UFH pipes e.g. rails https://underfloorparts.co.uk/product/underfloor-heating-clip-rail-track-1mtr-adhesive 1 Link to comment Share on other sites More sharing options...
Mike_scotland Posted March 11, 2021 Author Share Posted March 11, 2021 Thank you, all a learning experience for us. Link to comment Share on other sites More sharing options...
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