How to Improve Your Existing Home Energy Rating with a NatHERS Assessment
A NatHERS assessment for an existing home measures how energy efficient a home currently is. Conducted by an accredited assessor, it involves a detailed inspection of your home’s design, materials, and insulation, followed by computer modelling to determine thermal performance. The result is a NatHERS Certificate showing your property’s star rating and clear recommendations for improving comfort and efficiency.
What Is a NatHERS Existing Homes Assessment? The Nationwide House Energy Rating Scheme (commonly known as NatHERS) is Australia’s national framework for measuring the thermal performance of homes. It provides a star rating from 0 to 10, where higher ratings indicate better energy efficiency and lower heating and cooling needs. While NatHERS is commonly used for new dwellings, it can also assess existing homes. A NatHERS rating for existing homes helps homeowners understand how their property performs before undertaking upgrades or renovations.
It identifies where energy is lost through walls, roofs, windows, and gaps — empowering owners to make data-driven efficiency improvements.
Why Conduct a NatHERS Assessment for Existing Homes? A NatHERS existing homes assessment is more than just a compliance exercise. It’s an essential step in creating a comfortable, energy-efficient living space. Here’s why homeowners and renovators choose to undertake an existing home energy rating NatHERS assessment: ● Understand current energy performance: Identify weak spots in insulation, glazing, or orientation. ● Plan upgrades effectively: Prioritise improvements that deliver the biggest performance gains. ● Access incentives: Many sustainability programs and green finance options require a NatHERS Certificate. ● Boost property value: Homes with higher energy ratings are increasingly sought after by buyers. ● Save on bills: Improved thermal performance reduces the need for heating and cooling year-round.
How is a NatHERS Existing Homes Assessment Conducted? The NatHERS assessment is systematic and transparent, designed to capture every detail that affects your home’s performance.
Step
Process
Details
1. Initial Consultation
You share home details and goals
The assessor reviews any existing plans, photos, or renovation ideas.
2. Onsite NatHERS Assessor Visit
Physical inspection of the property
The assessor inspects materials, insulation, windows, orientation, and shading.
3. Data Collection
Detailed measurements and notes
Roof type, window specs, floor construction, and building fabric are recorded.
4. Energy Modelling
Simulation using accredited software
Tools such as AccuRate, FirstRate5, or HERO calculate heating and cooling loads.
5. NatHERS Certificate
Final rating and recommendations
You receive a NatHERS Certificate with your star rating and tailored improvement suggestions.
Each stage contributes to a thorough existing home energy rating (NatHERS) that reflects your home’s actual performance, not just its design intent.
What Happens During the Onsite NatHERS Assessor Visit? The onsite NatHERS assessor visit is central to the process. A qualified professional will spend one to two hours examining your home’s structure and condition. This includes: ● Checking insulation levels in walls, ceilings, and under floors. ● Recording window and glazing types (e.g., single or double glazing). ● Assessing building orientation and natural shading. ● Noting external features such as eaves, trees, and awnings. ● Identifying air leakage points around doors, vents, and ceilings. These observations ensure the final NatHERS rating for existing homes is accurate and reflective of real-world conditions.
How the NatHERS Rating for Existing Homes Is Calculated? After data collection, the existing home energy rating NatHERS assessor inputs the details into NatHERS-accredited software. The program simulates how much energy the home needs for heating and cooling over a typical year, based on: ● The local climate zone ● Building materials and construction type ● Orientation and shading ● Insulation levels ● Window performance and ventilation The model then generates a star rating between 0 and 10, with 6 stars generally considered the minimum benchmark for good performance. A higher rating means your home stays comfortable with less energy, cutting emissions and costs.
What’s Included in a NatHERS Certificate? Once the modelling is complete, you receive a NatHERS Certificate, which includes:
Section
Description
Energy Star Rating
The overall rating (0–10 stars) reflects thermal efficiency.
Heating and Cooling Loads
Separate figures for each zone or floor level.
Assessor Details
Accreditation information and software used.
Recommendations
Suggested upgrades to insulation, glazing, or sealing.
Compliance Statement
Confirms adherence to NatHERS protocols and standards.
This document is often required for council approvals or as part of broader sustainability reporting.
Using Your NatHERS Report to Improve Efficiency Your NatHERS existing homes assessment doesn’t just highlight problems — it provides a roadmap for solutions. Here are common improvement examples based on report insights: ● Add or upgrade ceiling and wall insulation. ● Install energy-efficient windows or apply window films. ● Improve shading through eaves, awnings, or trees. ● Seal draughts and gaps in doors, floors, and vents. ● Replace outdated heating and cooling units with efficient models.
How do Eco Certificates help? Eco Certificates provides accredited NatHERS Assessments for both new and existing homes across Australia. Our qualified assessors handle every stage — from the onsite NatHERS assessor visit to generating your NatHERS Certificate — with precision and transparency. We help homeowners, builders, and architects meet energy performance goals efficiently, ensuring your home achieves a high existing home energy rating under NatHERS.
Summary A NatHERS existing homes assessment is a great investment for anyone wanting to boost energy efficiency, comfort, and property value. Through expert inspection and modelling, you’ll receive a NatHERS Certificate that highlights exactly how your home performs — and what upgrades will make the biggest difference. Whether you’re renovating or simply aiming to reduce energy use, a professional NatHERS assessment provides the insights you need to build a greener, more sustainable future.
Contact Us
Eco Certificates Website: https://www.ecocertificates.com.au Email ID:
[email protected] Address: Suite G.03, 23 Ryde Road, Pymble NSW, Australia- 2073 Phone Number: +61 1300162436
