Changes to Part L - June 2022 New dwellings
1.Introduction
The revised (2021 edition) Part L issued in December 2021 came into force in June 2022.
The changes are significant and substantial.·
SAP 10 - with changes to the assessment methodology
Contact [email protected] for any updates or advice on this.
2.Key headlines:
1.U VALUE TARGETS are more challenging – so more insulation will be required:·
Element Typical required U Value , Limiting U Value Change
External walls including semi-exposed walls : U = 0.18 W/(m²·K) ( limit 0.26)
Floors: U = 0.13 W/(m²·K) (limit: 0.18)
Roofs: U = 0.11 W/(m²·K) (limit : 0.16) 0.02
Opaque door (less than 30% glazed area) U = 1.0 W/(m²·K) 0/ 0.04
Semi-glazed door (30–60% glazed area) U = 1.0 W/(m²·K) 0.2/0.04
Windows and glazed doors
with greater than 60% glazed areaU = 1.2 W/(m²·K) ( limit : 2.00) 0.2 / 0.04
Roof windows – ( Velux etc.. ) U = 1.2 W/(m²·K), 0.2
when in vertical position - Adjustments required for pitch
0.2
Rooflights ( Flat roof lanterns etc.. ) U = 1.7 W/(m2·K), 0
when in horizontal position Adjustments required for pitch
*100mm cavities are likely to become obsolete.
2.CONTINUITY OF INSULATION is considered in depth. Designers need to show a continuous insulation line on their drawings, and should consider including this section of the Approved Document in their specifications/ drawings.
3.EVIDENCE: Detailed photographic records are required as evidence for the SAP assessment.
4.THERMAL MASS: SAP assessors now have to calculate internal thermal mass.
5.THERMAL BRIDGING: Designers should consider including elements of the Thermal Bridging requirements section of the Approved Document in their specifications/ drawings.
6.ACCREDITED DETAILS for non-repeating thermal bridging are no longer be acceptable as evidence of good practice. Designers and builders need to use calculated Thermal Bridging details from other libraries together with their photographic record.
7.LIGHTING: The efficacy of all the lamps / lights will need to be specified. (typically: 80 lumens/m/W)
8.Showers: Flow rates need to be specified
9.Waste Water Heat Recovery: is included in SAP and is heavily weighted.
10.Solar PV is required more often than not to pass the SAP requirements, and for the ‘nominal compliant’ house with a gas boiler will be the equivalent of 40% of the roof area.
11.L1b- (Energy efficiency for existing buildings) has been in part integrated into the single Approved Document with L1a. Insulation standards have been increased and there are clearer definitions of when the regulations apply.
12.CARBON FACTORS : The carbon factors change in lot in favour of electricity meaning that it will be even harder to get a pass using fossil fuel heating.
13.Designers must show that they have considered the feasibility of high efficiency alternatives to traditional heating systems. ( Cogeneration, District Heating, Renewables and Heat pumps)
14.CRITERIA : There are now three pass and fail criteria in SAP instead of two :·Primary energy (Kwh/m2). This is influenced by the fabric and the fuel·Target Emissions Rate . This is influenced mostly by the services, and is the basis of the EPC rating ·The target fabric energy efficiency Rate. This is influenced mostly by U Values and air tightness.
1.Introduction
The revised (2021 edition) Part L issued in December 2021 came into force in June 2022.
The changes are significant and substantial.·
SAP 10 - with changes to the assessment methodology
Contact [email protected] for any updates or advice on this.
2.Key headlines:
1.U VALUE TARGETS are more challenging – so more insulation will be required:·
Element Typical required U Value , Limiting U Value Change
External walls including semi-exposed walls : U = 0.18 W/(m²·K) ( limit 0.26)
Floors: U = 0.13 W/(m²·K) (limit: 0.18)
Roofs: U = 0.11 W/(m²·K) (limit : 0.16) 0.02
Opaque door (less than 30% glazed area) U = 1.0 W/(m²·K) 0/ 0.04
Semi-glazed door (30–60% glazed area) U = 1.0 W/(m²·K) 0.2/0.04
Windows and glazed doors
with greater than 60% glazed areaU = 1.2 W/(m²·K) ( limit : 2.00) 0.2 / 0.04
Roof windows – ( Velux etc.. ) U = 1.2 W/(m²·K), 0.2
when in vertical position - Adjustments required for pitch
0.2
Rooflights ( Flat roof lanterns etc.. ) U = 1.7 W/(m2·K), 0
when in horizontal position Adjustments required for pitch
*100mm cavities are likely to become obsolete.
2.CONTINUITY OF INSULATION is considered in depth. Designers need to show a continuous insulation line on their drawings, and should consider including this section of the Approved Document in their specifications/ drawings.
3.EVIDENCE: Detailed photographic records are required as evidence for the SAP assessment.
4.THERMAL MASS: SAP assessors now have to calculate internal thermal mass.
5.THERMAL BRIDGING: Designers should consider including elements of the Thermal Bridging requirements section of the Approved Document in their specifications/ drawings.
6.ACCREDITED DETAILS for non-repeating thermal bridging are no longer be acceptable as evidence of good practice. Designers and builders need to use calculated Thermal Bridging details from other libraries together with their photographic record.
7.LIGHTING: The efficacy of all the lamps / lights will need to be specified. (typically: 80 lumens/m/W)
8.Showers: Flow rates need to be specified
9.Waste Water Heat Recovery: is included in SAP and is heavily weighted.
10.Solar PV is required more often than not to pass the SAP requirements, and for the ‘nominal compliant’ house with a gas boiler will be the equivalent of 40% of the roof area.
11.L1b- (Energy efficiency for existing buildings) has been in part integrated into the single Approved Document with L1a. Insulation standards have been increased and there are clearer definitions of when the regulations apply.
12.CARBON FACTORS : The carbon factors change in lot in favour of electricity meaning that it will be even harder to get a pass using fossil fuel heating.
13.Designers must show that they have considered the feasibility of high efficiency alternatives to traditional heating systems. ( Cogeneration, District Heating, Renewables and Heat pumps)
14.CRITERIA : There are now three pass and fail criteria in SAP instead of two :·Primary energy (Kwh/m2). This is influenced by the fabric and the fuel·Target Emissions Rate . This is influenced mostly by the services, and is the basis of the EPC rating ·The target fabric energy efficiency Rate. This is influenced mostly by U Values and air tightness.