Understanding and communicating the Home Energy Rating

What is a Home Energy Rating for an existing home?

A Home Energy Rating for an existing home provides a full assessment of how an already-built home uses energy and how easy (or difficult) it is to keep at a comfortable temperature. These are different from Home Energy Rating assessments for new homes. Find more information about existing home assessments, and how they differ from new homes assessments.

High versus low ratings

A high Home Energy Rating indicates a property that’s comfortable, energy efficient and cheaper to run. These qualities increasingly influence buyer and tenant decisions. Homes with higher ratings often attract more interest, hold their value and stand out in a competitive market.

Lower-rated homes represent a lot of potential. Home Energy Rating assessments offer a clear path for upgrades, with practical guidance that can reduce running costs, increase comfort and enhance future resale value. Whether selling or managing a property, understanding the rating helps you position it strategically.

Why higher ratings make a difference

Home Energy Rating assessments aren’t just numbers – they directly reflect a home’s comfort, running costs and resilience to extreme temperatures. Homes with higher ratings are often more attractive to buyers, leading to faster sales and higher sale prices.

There are two separate ratings on a certificate. A Home Energy Rating and a Star Rating. These ratings should be looked at together as they both provide important information.

A home with a high Home Energy Rating and a low Star Rating may be cheaper to live in but may be less resilient to temperature extremes, especially during a power outage. They require more energy to maintain comfort and rely more on heating and cooling systems than homes with a higher Star Rating.

The ratings are described below.

HOME ENERGY RATING	STAR RATING
The Home Energy Rating is based on the amount of energy expected to be used by the whole home, including its fixed appliances and any on-site solar and batteries.	The Star Rating is based on how much heating and cooling the home will need to stay in a comfortable temperature range.
Measuring energy efficiency A lower Home Energy Rating means higher energy bills. It costs more to live comfortably in a lower rated home. A higher Home Energy Rating means energy bills are lower. It costs less to live comfortably in a higher rated home. The current minimum Home Energy Rating in the National Construction Code for new homes and major renovations is 50 for apartments and 60 for houses.	Comfort in the home A 0-star rated home is quite uncomfortable to live in - too hot in summer and too cold in winter. It will require a lot of energy to heat and cool. A 7-star rated home will need a small amount of heating and cooling to keep it comfortable to live in. This is the minimum standard for new houses under the National Construction Code. A 10-star home is extremely energy efficient. It will remain very comfortable year-round, with limited or no heating or cooling needed to keep it comfortable to live in.
Running costs The difference between running costs for a low and high Home Energy Rating can be significant. A high rating means savings on household bills over time. Buyers and renters are increasingly aware of energy costs, with energy-efficient homes seen as more desirable, because they are more affordable to run as energy prices rise.	Running costs The difference between a 2 or 3-star and a 7-star home can mean thousands of dollars in energy bills each year. Buyers and renters increasingly view higher-rated homes as a safeguard against rising energy prices.

HOME ENERGY RATING

STAR RATING

The Home Energy Rating is based on the amount of energy expected to be used by the whole home, including its fixed appliances and any on-site solar and batteries.

The Star Rating is based on how much heating and cooling the home will need to stay in a comfortable temperature range.

Measuring energy efficiency

A lower Home Energy Rating means higher energy bills. It costs more to live comfortably in a lower rated home.
A higher Home Energy Rating means energy bills are lower. It costs less to live comfortably in a higher rated home.
The current minimum Home Energy Rating in the National Construction Code for new homes and major renovations is 50 for apartments and 60 for houses.

Comfort in the home

A 0-star rated home is quite uncomfortable to live in - too hot in summer and too cold in winter. It will require a lot of energy to heat and cool.
A 7-star rated home will need a small amount of heating and cooling to keep it comfortable to live in. This is the minimum standard for new houses under the National Construction Code.
A 10-star home is extremely energy efficient. It will remain very comfortable year-round, with limited or no heating or cooling needed to keep it comfortable to live in.

Running costs

The difference between running costs for a low and high Home Energy Rating can be significant. A high rating means savings on household bills over time.
Buyers and renters are increasingly aware of energy costs, with energy-efficient homes seen as more desirable, because they are more affordable to run as energy prices rise.

Running costs

The difference between a 2 or 3-star and a 7-star home can mean thousands of dollars in energy bills each year.
Buyers and renters increasingly view higher-rated homes as a safeguard against rising energy prices.

Achieving higher ratings

Making upgrades that improve the Home Energy Rating and Star Rating can be offset by energy bill savings over time.

If a loan is used to pay for the upfront cost of the upgrades, energy bill savings can often be greater than repayments on the loan. This means a household that makes upgrades can save money from day one.

There are different ways to upgrade a home and the best options will depend on the climate, type of home and technology used. A Home Energy Rating assessor can help households plan the most cost-effective upgrades.

Common buyer and renter questions

Essential information for agents and property managers

Buyers and renters increasingly ask about energy efficiency, and being prepared with clear answers builds credibility and trust. Here are some common questions real estate agents and property managers may encounter.

By preparing for these questions, agents and property managers can answer with confidence and position energy efficiency as a key part of the sales or rental conversation.

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What does a Home Energy Rating mean?

It is a measure of the overall energy use of the home taking into consideration the home’s design and construction as well as the energy efficiency of its appliances.

What does a Star Rating mean?

It measures how well the home’s design and construction keeps temperatures inside the home comfortable with minimal heating or cooling.

What’s the difference between the Home Energy Rating and the Star Rating?

The Home Energy Rating (from 0-100) measures the thermal performance of the home’s shell, plus the energy efficiency of appliances (e.g. heating, cooling, hot water, lighting, pool/spa pumps, rooftop solar (PV) and batteries). A home may rate over 100 where it generates and exports more energy than it uses.

The Star Rating (from 0-10) measures the home’s thermal performance and how well the building structure or ‘shell’ (i.e. floor, walls, roof, windows, insulation, orientation) keeps the home at a comfortable temperature.

Do higher ratings affect property value?

Yes. Homes with higher ratings can be cheaper to run, more comfortable to live in and are increasingly attractive to buyers and renters – which often translates into faster sales, higher prices and longer-term renters.

How do I know if a rating certificate is valid?

As an agent you should ask the seller or landlord if they have an official Home Energy Rating Certificate with the logo and QR code. You can check the certificate via the QR code or link included on the certificate. If the home has been renovated or upgrades made, a new assessment may be required.

Will the rating give me an idea of potential energy bills for the property?

Yes. The Home Energy Rating Certificate includes estimated annual energy use, which reflects how much energy the home is expected to use – and, where a solar (PV) system and household battery storage are present, how much energy it may generate and store. While it doesn’t show exact costs, it gives a strong indication of likely energy bills and overall efficiency.

Last updated

12 Aug 2026