01 / the gap
What does this home actually need?
Most installations are sized on a guess.
Households weighing solar, a battery, or a heat pump were quoted systems sized from a postcode and a recent bill. Two homes on the same street can need very different systems, and the difference only showed once the system was on the roof.
The goal was an estimate good enough to act on: the energy a specific home uses for heating and cooling, and what it could generate, before anyone climbs a ladder.
Two homes on one street
Same postcode, same bill band: one home needs more than twice the heating and cooling of the other.
02 / the build
Research → model → calibrate → explain
Start from the physics the research already measured.
Australia’s Nationwide House Energy Rating Scheme rests on decades of thermal research across climate zones and construction types. We built the model from that foundation: walls, glazing, insulation, orientation, and climate set heating and cooling loads; roof geometry and shading set solar yield.
Few homes come with plans, so the model works from what can be observed or asked—floor area, era of construction, roof aspect—and states its uncertainty whenever an input is missing.
- Stage 0101
Research
Thermal performance by climate zone and construction type, drawn from NatHERS research.
- Stage 0202
Model
Heating and cooling loads from envelope, glazing, orientation, and climate.
- Stage 0303
Calibrate
Estimates checked against metered consumption, with the uncertainty stated home by home.
- Stage 0404
Explain
A recommendation a household can read: what to install, what it will do, and why.
03 / the result
Installations sized on evidence
A better first recommendation.
Advisers could size systems home by home rather than postcode by postcode, and show each household the estimate behind the recommendation. Fewer systems were oversized, and homes that needed insulation before panels were told so first.
annual load estimate vs metered
oversized systems
NatHERS climate zones covered