Star ratings now cover existing homes.

Since 1 July 2026, NatHERS, now branded Home Energy Rating, rates existing homes as well as new designs. It is the scheme’s second stage. An accredited assessor models how the home’s design, construction and appliances perform in its climate, and the certificate gives a star rating out of 10 and the most cost-effective upgrades for that home.

The aim is to tell buyers and renters, before they commit, how efficient a home is and what it will cost to run. For owners, it shows where a home stands before a sale, a lease or a renovation, and which upgrades are worth paying for.

Our accredited assessors rate existing homes as well as new designs. And because we model how a house actually behaves, the upgrades we suggest are the ones that move the result most.