Brief definition
Usable floor area (NF) under WoFlV is the sum of areas of living and usable rooms in residential buildings. It is central to dwelling counts, comparability of housing offers, and many estimating metrics.
Distinction
NF is not identical to DIN 276 cost groups or to gross floor area (BGF). For tendering and BoQ, standards and cost-group assignment remain separate from pure living-area calculation.
AIGO relevance
AIGO determines room areas from calibrated 2D floor plans deterministically and exports structured values for planning and estimating — with a traceable audit trail.