* changes could increase costs by 4-8%.
* can comply using traditional materials.
* New requirement (20D): Designer must submit TER (CO2 target emissions rate for the building), DER (designed emissions rate) and a list of specifications. NB: any value engineering specification changes may require resubmission to Building Control.
* National Calculation Method (and software tools) used to comply with 20D.
* L1A - Dwellings: calculated using SAP. 25% improvement required.
Typical House of 128m2 (pass)
U-values: floor 0.13 (limit 0.25) ; walls 0.22 (limit 0.30 / party wall 0.20); roof 0.13 (limit 0.20); windows 0.15; door 0.1 (windows/doors limit 2.0)
Air pressure: 3m3/hour/m2 @ 50 Pa
Mechanical Ventilation with heat recovery: 1w per litre per second with 85% efficiency
Enhanced construction details
100% low-energy lighting
* L2A - Non-dwellings: also based on 25% improvement over 2006 standards. However, limiting u-values for commercial buildings are
unchanged.
Thermal bridging revisions.
Guidance on shell and core development revised: need to specify at design stage how requirements will be met. Also as-built
calculations. An Energy Performance Certificate must be provided.
* L1B & L2B: Refurbishment
Changes to minimum u-values to achieve 25% improvement.
Regulation 9: more relaxed approach for listed buildings. Potential exemption.
Change in definition of Renovation: - 50% of the element or 25% of the total envelope.
* L2 A Limiting U-values
Roof (0.25); Wall (0.35); Floor (0.25) Windows/Pedestrian doors (2.2)
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