My house has a 6.5 star HERS rating.
The Home Energy Rating Scheme is a new programme the government has started (this month) to provide standards based home energy audits. The assessments are carried out by nationally credited assessors.
My assessment was done by Steve is from Ecosphere. He spent 30 minutes measuring the house dimensions, walls, foot print and windows and documenting the insulation, space heating and hot water heating we've got. Then a few hours back at the office feeding the data into the special HERS software, plus some more to write up a list of improvement recommendations.
He says; "your house has a 6.5 star rating [out of 10] which is exceptional considering the age of your house. That second layer of insulation in your ceiling was worth half a star."
"...the only realistic recommendations that could be made for your house were, new sealed double glazed windows (which would save you approximately $50 a year in heating costs), and replacing your heatpump with a highly efficient 6 star rated unit, which if used in conjunction with a low voltage heat transfer system would be able to save you more."
It's nice to have external validation for what I've done. The windows were my main (low priority) insulation project going forward - so it looks like I'm on the right track.
It would be nice to get it up to 7 stars.
Here's the interim HERS report for our house.