Residential Performance
Australia’s existing homes are beginning to enter a more visible era of energy performance. The 2026 NatHERS Existing Homes Trial Outcomes Report marks an important step toward helping established homes be understood with more clarity, not just as buildings, but as places people live, renovate, improve and prepare for the future.
Most Australians do not live in new homes. They live in existing homes with different ages, materials, upgrades, comfort issues and energy costs. Some perform well. Others are difficult to heat, cool or improve without a clearer understanding of what is actually happening.
For new homes, NatHERS has long provided a structured way to assess thermal performance before construction. Existing homes have needed a more practical equivalent: a way to assess the homes already standing, already occupied and already shaping everyday comfort.
The trial tested whether that kind of assessment pathway could work in real conditions. The outcome is significant: the model was found to be viable and fit for purpose, while also identifying the improvements needed to make delivery more consistent, scalable and easier to integrate over time.
For homeowners, the most important shift is clarity. Without a rating, many upgrade decisions are made from visible symptoms: a cold room, high bills, old glazing, poor insulation or uncomfortable summer heat. Those signs matter, but they do not always show the whole picture.
A Home Energy Rating can help create a clearer starting point. It can support better decisions about insulation, glazing, heating and cooling, appliances, solar, electrification and future renovation priorities.
It also connects naturally with broader Whole of Home energy performance thinking, where the building fabric, appliances and future upgrades are considered together rather than separately.
The larger shift is not only about rating homes. It is about giving households, renovators and future buyers a clearer language for comfort, efficiency and upgrade readiness.
The trial included more than 1,000 assessments across a range of existing homes, dwelling types, climates and delivery conditions. It confirmed that ratings can be delivered in practice, while also showing that training, software usability, data quality and workflow integration are central to successful scale-up.
Assessment times improved as assessors gained experience, showing a clear learning effect. This matters because existing homes are rarely uniform. A scalable rating system needs to work across ordinary homes, complex homes and real property processes.
The report also highlighted the importance of connecting ratings with existing property, valuation and finance workflows. For home energy ratings to become useful at scale, the process must be practical for households and workable for industry.
Stage 1 of NatHERS Existing Homes commenced in July 2025. Stage 2 is expected to broaden access, with updated tools, expanded assessor accreditation and improved household-facing materials.
Over time, this may support future energy performance disclosure during sale or lease processes. If that occurs, existing homes could become easier to compare, and energy performance could become a more visible part of residential property decisions.
Certified Energy contributed to the national NatHERS Existing Homes trial and was referenced in the 2026 outcomes report as a high-volume delivery participant. Through this work, our team gained practical insight into what it takes to deliver ratings at volume, where workflows need to be strengthened and how the scheme can become more useful for households and industry.
For us, the purpose of this work is simple: helping existing Australian homes become easier to understand, more comfortable to live in and better prepared for the future.
Home Energy Ratings
If you are planning upgrades, preparing for future disclosure or simply want to understand your home’s comfort and efficiency, Certified Energy can help review the available information and confirm the next practical step.
Explore Home Energy Ratings