New build fabric standards are assumed to be equivalent to the Energy Saving Trust’s Advanced Practice Energy Efficiency standard, but with the air permeability standard relaxed to 3m3/m2.hr
The new build standard assumed for levels 2 and 3 is the middle specification (Specification C) of the five considered in the December 2009 consultation on fabric efficiency standards for zero carbon homes 
What should be included in this category?
Additional (from current building standards) material and labour costs in building a new house to passiv haus standards
What should be excluded from this category?
Anything beyond the cost of building the house: Land costs, final retail value etc.
Also, no additional profit or value of the property should be taken into account to reduce material and labour costs calculation.
How are these costs used in the 2050 Pathways model?
When the user chooses level 2 or 3 in housing thermal efficiency, all new build is assumed to be of this standard
- Department for Communities and Local Government (December 2009) Sustainable New Homes – The Road to Zero Carbon’. Consultation on the Code for Sustainable Homes and the Energy Efficiency standard for Zero Carbon Homes, page 68).