ALF 4.0 (Annual Loss Factor) is an online tool for determining the building performance index (BPI) of a house design.
The calculator can be used to demonstrate that a specific house design complies with New Zealand Building Code clause H1 Energy efficiency.
ALF 4.0 is an updated and completely redesigned version of the older ALF 3.2 calculator. This bulletin replaces Bulletin 555 A guide to ALF 3.2.
This bulletin covers: