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Game the Rating

One building, two rating systems, a fixed budget: hit the target, then see how much of your badge was real improvement and how much was clever measurement.

A NABERS IE star rates measured performance: five dimensions scored equally, then averaged into one star.

NABERS weights all five dimensions equally, so the overall star is just their average. You can raise a dimension two ways: a real upgrade that lifts what occupants actually experience, or a measurement tactic that changes when, where, or how you sample so only the reading moves. Because NABERS re-rates every three years with clean, full-period sampling, a rating built on tactics collapses at recertification while one built on real work survives.

NABERS IE Star Challenge

Five dimensions, each rated 1 to 6 stars from its measured performance; the overall star is their average (NABERS weights all five equally). Spend your budget on real upgrades (they lift what occupants experience and what the sensors read) or on cheaper measurement tactics (they lift only what the sensors read). Reach the target star without going over budget.

Target rating:
Intervention budget: pts
DimensionReal upgrade (raises true & measured)Measurement tactic (raises measured only)
The maths behind the star

Each dimension carries a true score (0 to 100, what occupants experience) and a measured score (what the rating sees). A real upgrade adds to both. A measurement tactic adds only to the measured score, because it changes when, where, or how you sample, not the building.

measured = clamp(true + tactic_inflation, 0, 100) dimension star = clamp(1 + measured / 20, 1, 6) overall star = mean of the five dimension stars

Real thresholds sit behind this (thermal = % time operative temperature inside the ASHRAE 55 band, roughly 75% for 4 stars and 85%+ for 5; IAQ = % time CO2 at or below 1000 ppm; acoustics at or below 55 dB(A) open-plan; lighting 300 to 500 lux with glare control; layout by m2/person and satisfaction). The 0 to 100 scale is a teaching simplification of those bands, not the NABERS algorithm.