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SuperHeat Information for SuperHeat users:

Part L, Part J and Part F requirements compared

Before Spring 2002 the Approved Document requirements for showing compliance with the requirement to take reasonable steps to ensure the conservation of fuel and power in dwellings were almost identical throughout the U.K. The Technical Booklet F requirements in Northern Ireland did not change in 2002. At first sight the Part L and Part J requirements, applicable in England & Wales and Scotland respectively, look to be almost identical (except for the widely publicised lower 0.3 U-value for external walls in Scotland) but there are numerous small differences which may mean that a particular building will comply with one or other set of requirements but not both. This page lists those differences that we have picked up.

Elemental Method standards: Dwellings with/without efficient heating

England & Wales Scotland Northern Ireland
Definition of efficient heating system Boiler SEDBUK efficiency 78/80/85% for gas/LPG/oil (82% for oil combi) as E&W SAP Rating>60
Minimum U-values:
External walls 0.35/not acceptable 0.30/0.27 0.45/0/45
Semi-exposed walls and floors 0.35/not acceptable 0.6/0.6
Exposed floors and ground floors 0.25/not acceptable 0.25/0.22 0.45/0.35
Pitched roofs 0.16/not acceptable 0.16/0.16 0.25/0.2
Pitched roofs with insulation between rafters in loft conversions 0.3 0.2 0.35
Flat roofs 0.25/not acceptable 0.25/0.22 0.35/0.2
Doors/windows/rooflights Max area 25% of floor area. Average U-value 2.0|2.2 metal|non-metal frames Max area 25% of floor area. Average U-value 2.0/1.8|2.2/2.0 metal|non-metal frames Max area 22.5% of floor area. Average U-value 3.3|3.0 metal|non-metal frames
If average U-value of openings is less than this ... No change (but larger opening area may comply when checked using Target U-value method) No change (but larger opening area may comply when checked using Target U-value method) Permissible area is increased
If average U-value of openings is more than this ... Permissible area is reduced Not acceptable(but may comply when checked using Target U-value method) Permissible area is reduced

Target U-Value Method

England & Wales Scotland Northern Ireland
Basic formula assumes all elements to Elemental Standard with pitched roof Yes Yes Yes
Higher target applies for flat roof or integral insulation roof dwelling No Yes No
Target U-value must be reduced (i.e. higher insulation required) for less efficient heating systems Yes Yes Yes (SAP<60)
Target U-value can be increased (i.e. lower insulation acceptable) for higher efficiency heating systems Yes No Yes
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Top Last revised 24 November 2004