NABERS - National Australian Built Environment Rating System EWO-3.4: Base the rating on acceptable data, with estimates within the 5 % limit

What does EWO-3.4 require?

3.4 and Appendix B.5: accurate, verifiable data must be used when it exists, in the preference order: data the assessor obtains directly; data from a disinterested third party (verifiable records such as utility bills, attested records, signed written information, or recorded verbal information naming the person); then data from the owner or an interested party (verifiable agreements, attested records, recorded verbal information). Estimates (assumptions, approximations, unvalidated data) may be used only as acceptable estimates, and their combined potential error must not exceed 5 % of the rating's emissions or water use, tested in the input form by comparing a Case A rating with a Case B rating in which area, hours and computer errors are added and consumption errors subtracted; above 5 % the building cannot be rated until better data is found.