What is NatHERS for Existing Homes?
A NatHERS Existing Homes assessment provides homeowners with Home Energy Rating Certificate to gain practical, cost-effective upgrade advice tailored to their ‘as built’ home.
The goal is to help reduce energy consumption, lower bills, enhance comfort, and increase the home’s resilience to extreme weather conditions.
An Existing Homes NathERS Assessor will evaluate:
Thermal Performance – This assesses how well a home retains heat in winter and remains cool in summer. Factors examined include insulation levels in walls, ceilings, and floors, the thermal efficiency of glazing, and air leakage through gaps, vents, and poorly sealed areas.
Whole of Home Energy Performance – This evaluates how efficiently a home uses energy for essential functions. It includes an assessment of heating and cooling systems, hot water systems, lighting, and major appliances such as refrigerators and washing machines. Additionally, on-site energy generation and storage systems, such as solar panels and battery storage, are considered to determine overall energy efficiency.
Key Elements Assessed:
Climate Zone, Exposure, and Orientation
Assessing the home’s location, sun exposure, and surrounding reflectance.
Windows and Doors
Assessing glazing, framing, and shading properties
Ceilings and Roofs
Measuring insulation levels and roof colour.
Zoning
Evaluating how different areas of the home are used and conditioned.
Floors
Inspecting insulation levels, materials, and underfloor ventilation.
Heating and Cooling Systems
Examining installed HVAC systems and efficiency.
Hot Water Systems
Evaluating efficiency and energy sources.
Walls & Shading
Identifying construction materials, insulation, and exterior colour. Evaluating eaves, verandahs, and other shading elements.
Air Leakage and Penetrations
Checking for draughts, vents, and chimney seals.
Lighting Systems
Identifying lighting types and energy efficiency.
On-Site Energy Production and Storage
Factoring in solar panels, batteries, and grid interaction.
Pools and Spas
Assessing heating and energy usage.
While not yet mandatory, assessments are encouraged when buying or selling a property, applying for green home finance, or planning upgrades or retrofits. In future, they may become standard practice in real estate and renovation markets.
What happens during the assessment?
The assessor will inspect the property in person. They will record construction details, measure windows and openings, check insulation, and note zoning and orientation in MagicPlan. No invasive work is required and most assessments are non-disruptive.
What you will need on the day.
To help your assessor complete the job efficiently, please provide:
Access to all rooms and the roof space if possible. Any available building plans or renovation documentation. Details of any upgrades or insulation added since the original build. A recent power bill.
The more information you can provide, the more accurate your rating will be.
How Long Does a NatHERS for Existing Homes Assessment Take?
Most physical site visits take between one and two hours depending on the size and complexity of the home.
After the visit, the report is typically delivered within 3-5 business days.
How Much Does a NatHERS for Existing Homes Report Cost?
The cost of a NatHERS Existing Homes assessment typically starts from $600 to $800 + GST depending on the size, complexity and location of the property.
We are happy to offer an obligation free quote based on your property details. Contact us today to find out more or to request a tailored quote for your home.
What you will receive:
Once the assessment is complete, you will receive a NatHERS Certificate that includes:
A star rating between 0 and 10
Heating and cooling load figures in megajoules per square metre
A floor plan summary and description of key construction details
Optional upgrade recommendations to improve your rating
This report can be used to support renovations, property listings, green finance applications or simply to understand your home's performance better.
More information?
