Projects using Welsh Regulations

What is written here applies only to projects using Welsh 2022 Regulations.

You should read the NCM modelling guide for Wales and be familiar with it.

For Wales, Cardiff weather data must be used.

Notional PV area

For full details, see sections 80-81 of the National Calculation Methodology (NCM) modelling guide (for buildings other than dwellings in Wales).

The area of PV in the Notional building is equal to 10% of the building’s gross internal area, or 50% of the building’s roof area, whichever value is smaller.

NB: EDSL have been advised that for buildings with zero roof area, the area of Notional PV will be equal to 10% of the building’s gross internal area. This means that all projects will have PV in the Notional building, even those with zero roof area.

District Heating

For district heating systems, set the heat generation efficiency to 100%.

A district heating network should NOT be marked as a heat pump in the studio, even if the heat source for the district heating is wholly or partly a heat pump.

CO2 and Primary Energy factors should be calculated for the network using the method described in Approved Document L volume 2 and the fuel factors from table 33 of the NCM modelling guide for Wales.