Example 1:

Semi-detached house (126 m2): hollow blocks walls with 25 mm mineral wool internal insulation, pitched roof with 50 mm mineral wool insulation on the ceiling, double glazing with 6 mm air gap, 80 % gas boiler installed with no heating controls, solid fuel stove secondary heating.

Proposed works to elements1	Major renovation (Yes/No)	Required additional works
A) Window replacement (13 % of envelope)	No	NA
B) EWI or IWI of walls (35 % of envelope)	Yes	Upgrade insulation at ceiling level to 0.16 W/m2K or better as per table 5, and 90 % efficiency condensing gas boiler replacement and controls upgrade: time and temperature controls for space heating + time and temperature controls on domestic hot water
C) EWI or IWI of Walls and windows replacement (48 % of envelope)
D) EWI or IWI of Walls and replacement of roof structure (61 % of envelope)
E) EWI or IWI of Walls and replacement of floor (61 % of envelope)

¹ Major Renovation of all elements should meet the requirements of Table 5 where material alteration applies.

Primary energy consumption before major renovation: 233 kWhr/m2/yr

Proposed works package B) is based on the following specification: 100 mm EWI, 300 mm attic insulation, 91 % efficiency gas boiler, full zone time and temperature controls on space heating with weather compensation, time and temperature control on domestic hot water with insulated primary pipework.

Primary energy consumption post major renovation: 121 kWhr/m2/yr

Example 2:

Terraced house (96 m2): solid wall, pitched roof with 50 mm mineral wool insulation on the ceiling, double-glazing with 12 mm air gap and a U-value of 2.8 W/m2K, 68 % efficiency gas boiler installed with no control.

Proposed works to elements1	Major renovation (Yes/No)	Additional works
A) Window replacement (15 % of envelope)	No	NA
B) EWI or IWI of walls (22 % of envelope)	No	NA
C) EWI or IWI of walls and ceiling insulation (53 % of envelope)	No2	NA
D) EWI or IWI of Walls and windows replacement (37 % of envelope)	Yes	Upgrade insulation at ceiling level to 0.16 W/m2K or better as per table 5, and 90 % efficiency condensing gas boiler replacement and controls upgrade: time and temperature controls for space heating + time and temperature controls on domestic hot water
E) EWI or IWI of Walls and replacement of roof structure (53 % of envelope)
F) EWI or IWI of Walls and replacement of floor (53 % of envelope)

¹ Major Renovation of all elements should meet the requirements of Table 5 where material alteration applies.

² Ceiling insulation is not replacement of the roof structure.

Primary energy consumption before major renovation: 187 kWhr/m2/yr

Proposed works package D) is based on the following specification: 50 mm IWI, windows at 1.4 W/m2K, 300 mm attic insulation, 91 % efficiency gas boiler, time and temperature zone controls on space heating with weather compensation, time and temperature control on domestic hot water with insulated primary pipework.

Primary energy consumption post major renovation: 107 kWhr/m2/yr

Appendix F Major Renovations Compliance Examples

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