Part L and NZEB — the performance the pack has to prove
Part L (Conservation of Fuel and Energy) sets the energy-performance requirements, and Ireland's transposition of the nearly zero-energy building (NZEB) standard applies to new dwellings and new non-domestic buildings, with major-renovation requirements for existing stock. The performance is demonstrated through the relevant calculation methodology and carried in the specification, the schedules and the BER/energy documentation.
On the document-quality side the questions are whether the specification actually delivers the fabric and services performance the energy calculation assumed — U-values, air-tightness, ventilation strategy, the renewable contribution — and whether those figures are consistent everywhere they appear. A specification cut from an earlier project can quietly carry the previous job's U-values or a superseded methodology reference, which is precisely the kind of currency gap a read is built to surface.