NatHERS vs Passive House: What’s Right for Your Home or Project in Adelaide?

A Practical Guide for Homeowners and Architects

Executive Summary

This guide compares two leading approaches to residential energy efficiency in Adelaide and the Adelaide Hills: Australia’s Nationwide House Energy Rating Scheme (NatHERS) and the international Passive House standard. Both aim to create comfortable, energy-efficient homes, but differ in philosophy, requirements, and outcomes.

​Most people focus on the visible differences, but to know which is right for you, we need to look deeper.

NatHERS

is Australia’s mainstream system, rating homes from 0 to 10 stars based on design features like orientation, insulation, and shading. It is primarily a design-based assessment, widely used for building approvals, and focuses on cost-effective compliance with the National Construction Code. However, it does not require post-construction testing, so actual performance may vary depending on build quality. To find out more how I can help, see New home, energy efficiency consultation - YOUR LOW ENERGY HOME

Passive House (Passivhaus)

originating from Germany, is a rigorous, performance-based standard. It requires strict limits on energy use, airtightness, and indoor comfort, verified through third-party testing. Passive House homes feature superior insulation, airtight construction, and mechanical ventilation with heat recovery, resulting in exceptional comfort, low energy bills, and healthy indoor air quality. This approach involves higher upfront costs and specialized skills but delivers long-term value and resilience. To find out more how I can help, see Passive House Design Services - YOUR LOW ENERGY HOME

In Adelaide’s Mediterranean climate (warm temperate)

NatHERS offers a practical, familiar route for compliance and moderate cost, while Passive House provides best-in-class comfort and energy savings, especially for those prioritizing health and long-term performance. A hybrid approach—either using NatHERS for compliance and incorporating Passive House principles or alternatively designing to Passive House, but operating like a NatHERS home—can help achieve optimal results.

Conclusion:

Both standards support Australia’s move toward healthier, more efficient homes. The right choice depends on your priorities: NatHERS for ease and affordability, Passive House for superior comfort and performance. Combining elements of both can deliver the best outcomes for Adelaide’s unique climate and evolving housing needs.
If you are thinking of building or renovating, contact me for a free discussion of your needs.
For a deeper dive, keep reading.

---

A detailed comparison

​Introduction

​Are you planning a new home or looking to elevate your building designs in Adelaide? If so, you’ve likely come across sustainability buzzwords like NatHERS and Passive House. But what do they actually mean for your comfort, costs, or project outcomes? This blog breaks down these two approaches—Australia’s NatHERS rating and the international Passive House standard—to help both homeowners and architects make informed decisions in Adelaide and the Adelaide Hills’s unique climates. Refer Where is my homes energy going? - YOUR LOW ENERGY HOME for why you should focus on information and consultants targeting your local climate.
Often when people look at Passive House they focus on the typical physical differences, but to understand what is best for you, you should look at the philosophical differences (see key differences below).

Understanding NatHERS: Australia’s Home Energy Rating System

The Nationwide House Energy Rating Scheme (NatHERS) is an Australian government system that assesses how well a home’s design keeps you comfortable year-round with minimal heating or cooling. You’ll see homes rated between 0 and 10 stars based on factors like orientation, insulation, glazing, and shading—think of it as a “first pass” on energy efficiency.

• Why it matters: NatHERS is the most common route for building approvals.
• Requirements: The National Construction Code requires a minimum 7-star NatHERS rating for most homes.
• How it works: Modelling is based on your plans, not post-construction tests, so it’s important to build as designed to achieve a comfortable and low energy home.
• Consequences: a seven star home (if assessed and built correctly) will be more comfortable than a three star home (typical of homes built before energy efficiency requirements were introduced.)

​​If you have specific questions, contact me.

What’s Passive House?

Passive House (or Passivhaus) comes from Germany but is growing in Australia. It’s a global gold standard for energy-efficient, ultra-comfortable homes. Unlike NatHERS, Passive House is performance-based: you must meet strict targets not just in the design, but also in the way the building is actually built and tested.

• Why it matters: Passive House aims for dramatically lower heating and cooling bills and exceptional comfort, regardless of external temperatures.
• Requirements: Rigorous limits on heating/cooling energy, airtightness, and indoor comfort, plus third-party certification to prove it.
• How it works: Features like double-glazed windows with high performance frames (Timber or uPVC), thick insulation, very airtight but with mechanical ventilation (with heat recovery) are standard.
• Consequences: If heated and cooled as assessed by the planning package the whole house will be comfortable all the time. However, many houses in Australia are actually heated and cooled as a hybrid, with only one or two wall splits, rather than every room heated. This leads to a lower energy use as wall splits are the most efficient way of heating (more efficient than a ducted system), and you are not maintaining the whole house at comfort temperatures all the time. But this means not all areas are heated. The heat recovery ventilator does spread the heat out, and the good building fabric prevent any room getting freezing but it doesn’t quite meet the original intent but in much of Australia achieves acceptable conditions, which will be more comfortable than a seven star home with wall splits.

​​​​If you have specific questions, contact me.

Key Differences at a Glance

Origin
NatHERS Australia
Passive House Germany (International)

Philosophy
NatHERS Follows the traditional Australian approach of only heating and cooling rooms when you use them. For a given level of comfort, this will use less energy in a Mediterranean climate.
Passive House Follows the northern European approach of keeping all rooms comfortable all the time. This is because if it is -20C outside, you can’t afford to have the bathroom freezing, apart from the comfort, you risk your water pipes freezing and bursting.

Consequences of the philosophy
NatHERS Lower cost building as not all rooms need to be insulated to the same level as a Passive House.
Passive House Higher cost building, but a significantly better level of comfort.

Rating
NatHERS 0–10 stars (modelling only)
Passive House Pass/Fail, strict targets and testing, although there are different levels of Passive House

Focus
NatHERS Thermal performance on paper
Passive House Verified performance: energy, airtightness, comfort, air quality

Testing
NatHERS No onsite testing required
Passive House Blower door airtightness test mandatory

Ventilation
NatHERS Natural ventilation only. (although the building code addresses short term mechanical ventilation in some rooms)
Passive House Mechanical ventilation with heat recovery (MVHR) standard

Adelaide’s Climate: Why Context Matters

With its hot, dry summers and cool, wet winters, Adelaide’s Mediterranean climate presents unique challenges for home comfort and efficiency. The difficulty of achieving comfort in Adelaide is illustrated by the fact that South Australia was the first state to reach 90% of homes with some form of air conditioning, in spite of being the poorest mainland state. It should also be noted that in most homes winter heating dominates energy use, rather than summer cooling.

NatHERS in Adelaide

NatHERS software is adapted to Adelaide’s conditions, encouraging smart passive design—like optimising your orientation, shading, and insulation. This approach is effective for compliance, cost control, and familiar to local builders. Keep in mind, though, that the final result depends on quality construction, as there’s no mandatory testing once the home is built.

• Integrates smoothly with planning and building processes
• Cost-effective and widely used in the local industry
• Potential gaps between what’s designed and what’s built

Passive House in Adelaide

For those wanting to push the envelope—whether you’re an architect, developer, or adventurous homeowner—Passive House delivers year-round comfort and consistency. Superior insulation, airtightness, and controlled ventilation mean homes stay cool in summer and warm in winter, with minimal energy bills and excellent air quality.

• Achieves a higher level of comfort
• Slashes heating and cooling costs compared to a pre energy efficiency requirement home, and generally a lower energy cost than a 7 star home
• Creates a healthy indoor environment with constant controlled fresh air
• Requires higher upfront investment and specialised skills, but delivers long-term value
• Increasing local expertise as Passive House gains traction in Adelaide

So, Which Approach is Right for You?

The bottom line:

• For ease of building and building approval: NatHERS is the easiest route to meet building codes at the lowest cost.
  • Incorporating ideas from Passive House can lead to a more comfortable, lower running cost home.
• For best-in-class comfort and performance: Passive House is in a league of its own, but requires more careful design and construction oversight.
• For Adelaide’s unique climate: Passive House offers comfort and resilience—especially for those building for the long-term or prioritising health, comfort and energy savings.
• A Passive House with a hybrid heating and cooling approach, can offer a higher level of comfort than a similar seven Star home, with a similar or lower energy cost, but a higher construction cost.

​​​If you are looking to build or have questions, contact me.

Conclusion: Blending Strengths for Better Homes

Both NatHERS and Passive House support Australia’s transition to healthier, more efficient homes. In Adelaide, where climate extremes are the norm, using NatHERS for compliance and drawing on Passive House principles for design and construction can help you achieve the best of both worlds. Alternatively, designing the fabric to Passive house standards, but heating and cooling in the way NatHERS assumes, can also achieve a great solution.
Whether you’re a homeowner navigating your build or an architect seeking to stand out, understanding the differences between these standards will empower you to make smarter, future-proof choices for Adelaide’s evolving built environment. If you are thinking of building or renovating, contact me for a free discussion of your needs.