NatHERS, the Nationwide House Energy Rating Scheme, is Australia's national system for rating how energy-efficient a home is. It uses accredited software and CSIRO modelling to assess how well a home holds comfortable temperatures and how much energy it uses, producing a nationally consistent rating.

The star rating measures thermal performance on a scale of 0 to 10. It reflects how much heating and cooling a home needs to stay comfortable, based on its design, orientation, insulation and glazing. A higher rating means a more comfortable, cheaper-to-run home.

A 10 star home needs almost no mechanical heating or cooling to stay comfortable year round. It represents the top of the thermal scale. Most existing homes sit much lower, which is why an assessment is useful for finding improvements.

NatHERS uses validated CSIRO modelling and accredited assessors to produce consistent, reliable results. It models a full year of local climate conditions, so it reflects how a home performs in its specific location rather than a generic estimate.

For most new houses and townhouses, yes. A NatHERS assessment is the most common way to demonstrate compliance with the energy efficiency requirements of the National Construction Code, and a certificate is generally needed before a building permit is issued.

New houses and townhouses must reach a minimum 7 star thermal rating plus a Whole of Home score of at least 60 out of 100. New apartments must average 7 stars with no unit below 6, and reach a Whole of Home score of at least 50.

Since the 2022 National Construction Code update, new homes must achieve at least 7 stars for thermal performance, up from the previous 6 star minimum. A 7 star home typically needs 20 to 25 percent less heating and cooling energy than a 6 star home.

As early in the design as possible. Modelling the design before plans are finalised lets you test cost-free improvements like orientation and window placement. Fixing a shortfall after construction documents are locked in is far more expensive.

It is the official document showing your star rating, Whole of Home score, modelled heating and cooling loads, and climate zone. Your building surveyor or certifier uses it as evidence of energy efficiency compliance.

Major renovations and extensions can trigger a NatHERS assessment, depending on the scope of work and your state or territory rules. If you are significantly altering the building shell, it is worth checking early.

No. NCC 2025 introduced no new residential energy efficiency measures, and further residential changes have been paused, so the 7 star and Whole of Home framework remains the standard for the foreseeable future.

In NSW, thermal performance is assessed through BASIX rather than NatHERS directly, with targets aligned to the 7 star standard. The compliance pathway differs, but the underlying performance outcome is comparable.

Yes. New home assessments are based on your plans and specifications, so they can be completed remotely from your documentation, wherever the project is located in Australia.

Yes. NatHERS has expanded to rate homes that are already built. An accredited assessor visits, records how the home is constructed and equipped, and produces a star rating and a Whole of Home rating along with practical improvement advice.

No. The assessor gathers everything needed during the home visit, so plans are not required. Any plans or renovation records you do have can help confirm hard-to-see features, but they are not essential.

The assessor records construction and materials, insulation, windows and glazing, shading, orientation, ventilation, and your heating, cooling, hot water and any solar. The visit is non-invasive and usually takes a couple of hours.

Because it turns guesswork into a plan. It shows where your home wastes energy so upgrades are targeted, and it adds credibility when selling, leasing or applying for green finance. It is useful whether you stay for decades or sell next year.

Not at this stage. It is currently voluntary, but it is being requested more often for property sales, renovations and green finance, and governments are trialling energy rating disclosure at sale and lease.

It is the part of a NatHERS assessment that scores your home's total energy use out of 100. It combines the energy used by major fixed appliances with the energy generated by any solar, giving a single measure of efficiency and running cost.

Higher is better. Below 40 is a poor performer, 60 is the compliance minimum for a new house, and 100 represents a net zero energy home with low or no energy bills. Scores above 100 are possible.

Yes. A score above 100 means the home generates more energy than it uses across the year, typically through a well-sized solar system, and exports the surplus. These homes usually have very low or no net energy bills.

The star rating out of 10 measures the building shell. The Whole of Home rating out of 100 adds appliances and subtracts solar. The star rating is about how the home is built, the Whole of Home rating is about how it is run.

For a new home, an assessor models your plans in accredited software. For an existing home, an assessor visits and records the home's details. Both are calculated using CSIRO-based software to produce your ratings and recommendations.

Accredited tools such as AccuRate, FirstRate5 and BERSPro for new homes, and AccuRate Enterprise for existing homes. All are built on the CSIRO Chenath engine and produce nationally consistent results.

Only an accredited NatHERS assessor. Accreditation involves training and ongoing professional development to ensure ratings are accurate and consistent. It is always worth confirming your assessor is accredited before booking.

An existing home visit usually takes a couple of hours, with the report following within a few business days. A new home assessment depends on the complexity of the plans. Ask for a timeframe when you request a quote.

It depends on the size and complexity of the home and whether it is a new build or existing home. The best approach is to request a clear, fixed quote up front so there are no surprises.

For most homes, yes. It turns vague concerns about comfort and bills into a clear plan, helps you spend upgrade money in the right order, and can support compliance, sale and finance, often paying for itself.

Evidence suggests so. Energy-efficient homes in Melbourne have been shown to command a significant price premium over comparable inefficient homes, reflecting growing buyer demand for comfort and low running costs.

State-based. Residential tenancy law sits with each state and territory, so minimum rental energy standards and their timing differ across Australia. There is no single national rental standard.

They phase in from 1 March 2027, with further requirements from 1 July 2027 and a final cooling requirement for all rentals from 1 July 2030. Many requirements are triggered at the start of a new or periodic lease.

Ceiling insulation where none exists, efficient electric heating and hot water as systems reach end of life, efficient cooling in the main living area, draught proofing of doors, windows and wall vents, and 4-star showerheads, phased across the deadlines.

It varies by home, but the biggest levers are usually ceiling insulation, draught sealing, glazing improvements, efficient electric heating and cooling, heat pump hot water, and rooftop solar. An assessment shows your priorities.

Electrification means replacing gas appliances with efficient electric ones, such as swapping gas heating for a reverse-cycle system and gas hot water for a heat pump. Paired with solar, it typically lowers running costs and emissions.

It can. As energy rating disclosure becomes more common at sale, a strong rating reassures buyers about comfort and running costs, and can help an efficient home stand out in a competitive listing.

A green home loan is a home loan with a discounted interest rate for properties that meet certain energy efficiency standards. Many lenders link the discount to a NatHERS rating, so an efficient home can mean a cheaper loan.

It can. A number of lenders offer rate discounts for homes with a NatHERS rating of 7 stars or higher. A strong rating is the evidence these lenders look for, which is one of the practical benefits of having your home rated.