<![CDATA[YOUR LOW ENERGY HOME - NCC 2022 Blog]]>Thu, 14 May 2026 11:51:20 +0930Weebly<![CDATA[NatHERS vs Passive House: What’s Right for Your Home or Project in Adelaide?]]>Thu, 23 Oct 2025 00:44:04 GMThttps://www.lowenergyhome.com.au/ncc-blog/nathers-vs-passive-house-whats-right-for-your-home-or-project-in-adelaideA 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.
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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.
]]><![CDATA[Is it time to rethink windows?]]>Tue, 01 Apr 2025 01:06:33 GMThttps://www.lowenergyhome.com.au/ncc-blog/is-it-time-to-rethink-windowsWindows are an essential part of our homes and buildings, providing natural light, ventilation, and a connection to the outside world. However, they also come with costs that we often overlook. In this post, we'll explore the historical background, cost of windows in terms of energy flows, the price of high-performance windows, the extra cost of complying with energy efficiency requirements for large windows, why we have windows and glazed doors in the first place and what we can do to keep the benefits but minimise the costs.

Why We Have Windows and Glazed Doors

​Despite the costs associated with windows, they remain a crucial element of building design. Windows and glazed doors provide natural light, which can improve mood. They also offer ventilation, helping to maintain indoor air quality. Additionally, windows can connect us to the outside world, providing views and a sense of openness and oneness with nature. These benefits make windows an indispensable part of our homes and buildings, even as we work to improve their energy efficiency.

Historical background

​If you consider homes built in Australia built before the fifties, they had small windows because the predominant form of heating was open wood fires. Because they are not an effective form of heat and insulation was rare, windows were as small as possible to reduce heat loss so the rooms could be heated to a moderately comfortable temperature. The small windows also minimised summer heat gain. Because house comfort levels were so poor, most people were aware of the comfort cost of windows.

Frank Lloyd Wright (1867-1959) an American Architect is generally attributed with developing the concept of large glass windows connecting to the outside which has been embraced in Australia. The early Australian exponent of this concept was Robin Boyd (1919-1971).

However, you need to recognise Frank Lloyd Wright was designing for the wealthy who could afford the high heating costs of the buildings, and he experimented with early air conditioning systems to try and keep them cool. Although he later embraced the use of shading to maximise winter warmth and minimise summer heat build-up, these techniques are insufficient in South Australia to achieve comfort all the time.

It should be noted that even Frank Lloyd Wright implicitly recognised his homes didn’t give year-round comfort and he later lived in Chicago in the summer, and Arizona in the winter.

During the 1970’s builders in Australia realised that the construction cost of a square meter of brick veneer wall and a square meter of single glazed aluminium sliding windows was the same. This meant a show home could be built with large windows facing a landscaped garden to give the wow factor that closed the sale. Because the show home could have air conditioning and people were less likely to go out on an extremely hot or cold day (cars didn’t have air conditioning) people didn’t notice the problems until after the house was built.

The problems with excessive windows include:
  • High cost of compliance with the National Construction Code
  • the high cost of window treatments
  • poor comfort in hot and cold weather (even with window treatments)
  • high heating and cooling costs

Because expectations in Australia have moved to large, often floor to ceiling windows, to achieve the star rating can be expensive. We need to minimise these negatives while still retaining the positives of light and the connection to the outside.

The Cost of Energy Flows Through Windows

​Windows can be a significant source of energy loss in a building (up to 40% of energy loss in existing homes that I energy audit). During the winter, heat escapes through windows, leading to higher heating costs. In the summer, windows let in unwanted heat, increasing the need for air conditioning. It's essential to consider these energy flows when designing or renovating a building to ensure energy efficiency.

​You also need to spend money on curtains or blinds, even in a 7-star home, so avoiding excessive windows also reduces this cost.

The Extra Cost of Complying with Energy Efficiency Requirements

Large windows can be a beautiful feature in a building, providing ample natural light and stunning views. However, they also come with additional costs to comply with energy efficiency requirements. 

High-performance windows are designed to minimize energy loss and improve a building's overall energy efficiency. These windows often feature multiple panes of glass, low-emissivity (Low-E) coatings, and Argon gas between the panes to reduce heat transfer. They also have high performance window frames. While high-performance windows are more expensive upfront, they lead to significant energy savings over time.

In fact, if you have a lot of glass, you won’t be able to achieve a 7-star rating without high performance glass. This is the main driver of increased costs for 7-star homes. However careful design can minimise this cost. The Australian Glass Window Association research has shown the average premium is $4,300, not the $40,000 plus premium touted by the Housing Industry Association (although this latter figure is possible, if you don’t consider windows, orientation and building form carefully).

However, it is possible to achieve the benefits of windows with substantially smaller windows that are common today, but you need to start considering these ideas when considering the block and house concept, not when you have detailed designs as the costs will already be locked in. See How early design decisions impact the cost of achieving energy efficiency in homes - YOUR LOW ENERGY HOME and Optimal House Orientation in Adelaide: More Than Just Facing North
- YOUR LOW ENERGY HOME

A future knowledge base post will address how we can achieve this and achieve a lovely home at an affordable cost.

In the meantime, contact us to get started on the energy efficiency planning for your home as early as possible.

Conclusion

​While windows offer significant benefits, they come with costs in terms of energy flows, comfort,  window treatments and the cost of compliance with energy efficiency requirements. By careful design we can achieve the benefits with smaller windows than is common today, minimising the cost of high-performance windows, and we can enjoy the advantages of windows while minimizing their impact on our hip pocket.
​
​Contact us to get started on the energy efficiency planning for your home as early as possible.
Contact us
]]><![CDATA[Save money by considering energy efficiency early in home design]]>Mon, 24 Feb 2025 00:15:44 GMThttps://www.lowenergyhome.com.au/ncc-blog/how-early-design-decisions-impact-the-cost-of-achieving-energy-efficiency-in-homesEarly design decisions (even as early as choosing the block and associated building shape) have a significant and often overwhelming impact on a new home or renovation final cost, particularly with respect to meeting energy efficiency requirements. The majority of the cost is locked in during the initial conceptual stages, as correcting early design decisions is significantly more expensive due to the ripple effects on other decisions.

Key points about the impact of early design choices on building cost to meet energy efficiency requirements:

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Showing typical relative costs to achieve a 7-star energy efficiency rating at different stages of the design process. The earlier in the process you introduce an energy efficiency advisor, the lower the eventual cost to achieve the required rating.
  • High percentage of cost locked in early:
Studies show that up to 80% of a building's total cost can be determined during the early design phases, making these decisions highly critical for budget management. 
  • Cost of change escalates later:
Modifying design elements during detailed design, often results in increased costs due to the need to, for example, employ more expensive components, to avoid having to redesign the whole building. 
​
  • Factors impacting cost in early design:

  • Site selection: The site and the building concept generally, have the biggest impact on overall costs. This is not about whether the site faces north, but is about whether the proposed building concept is compatible with the block and its orientation.  
  • Building footprint and orientation: The size and shape of the building, along with the orientation of windows relative to the sun, can impact energy efficiency and the need for more expensive components to meet energy efficiency requirements. 
  • Window size and orientation: excessively large windows particularly if facing the wrong way have an enormous impact on the cost of compliance. Poor decisions can result in doubling or more the cost of windows.
  • Material choices: Early decisions on materials like exterior cladding, roofing, and interior finishes can significantly influence overall cost. 
  • Structural Complexity: The complexity of the building’s structure is another critical factor. Intricate designs with complex shapes or elaborate details require specialized skills and more time to construct, driving up labour costs. For example, a complex roof design, can make installing solar more expensive, increase the risk of roof leaks, place more constraints on air conditioning system design in addition to being more expensive. Simplifying the structural design can make the building process more efficient and cost-effective, without necessarily compromising on functionality or aesthetics.​

Benefits of careful early design consideration:

  • Cost optimization: By proactively evaluating design options during the initial stages, architects and engineers can identify cost-effective solutions and minimize unnecessary expenses. 
  • Improved constructability: Well-thought-out design plans with clear details can streamline construction processes, reducing potential delays and rework. 
  • Enhanced energy efficiency: ​Early design decisions regarding building orientation, glazing, and insulation can significantly influence both the cost of compliance and ongoing energy consumption and operational costs. 

Strategies to manage early design cost implications:

  • Matching the building to the block: Whether starting with a block you want to develop, or have a home concept in mind, they need to be compatible. I have recently seen a case where a different building concept would have resulted in a very affordable home, but because the architectural drawings were nearly complete, the cost to meet energy efficiency requirements was significant. Low Energy Home is prepared to offer a free one-hour meeting to address this, even before you buy a block. See also House orientation, more than facing north.
  • Detailed budget planning: Establishing a clear budget early in the design process and regularly monitoring against it. 
  • Value engineering: Evaluating different design options to identify cost-effective alternatives without compromising functionality. 
  • Collaboration between the designer, energy efficiency advisor and contractor: Fostering open communication as early as possible to identify potential cost issues and incorporate constructability considerations early on. As part of the energy efficiency assessment, Low Energy Home is prepared to have a discussion with the client and the architect or building designer at concept design stage to ensure low-cost energy efficiency provisions aren’t designed out at the concept phase. This is particularly important with the introduction of NCC 2022.

To find out how I can help you cost effectively achieve a 7-star energy rating go to Architect and Builder Services. or Contact us
Architect and builder services
]]><![CDATA[Optimal House Orientation in Adelaide: More Than Just Facing North]]>Fri, 10 Jan 2025 00:24:26 GMThttps://www.lowenergyhome.com.au/ncc-blog/optimal-house-orientation-in-adelaide-more-than-just-facing-north

Understanding the Best Orientation for a Home

When it comes to building a house in Adelaide, the conventional wisdom suggests that facing a home north is the ideal orientation. However, this is not always the case. The shape of a block and the type of home you intend to build are crucial factors that influence the best orientation for a specific situation. By choosing the right orientation for a home, you can reduce costs and enhance comfort.

Factors Influencing House Orientation

The Importance of the Block Shape

The shape and size of a block significantly impact the optimal orientation of a house. For instance, if you have a deep and narrow block, you may be forced to use a different home layout than if you have a wide fronted block. The wider the frontage, the more flexibility you have in designing a home with either large windows facing the street or a patio at the back. However wider frontages tend to be more expensive, regardless of whether it is an infill development or a greenfield site.

The Type of Home You Want to Build

The design and layout of a home also play a pivotal role in determining the best orientation. If your house design includes large windows facing the street, a north-facing block may be optimal as it allows for passive solar heating and natural light. However, if you prefer large windows overlooking a backyard patio, a south-facing block might be more suitable. If the block faces south the main windows can face north and open onto the back yard giving a very pleasant aspect.

Window Orientation Over Block Orientation

While the block's orientation is important, it is through how it influences the shape of a house and orientation of the windows and is not inherently important by itself. The placement and size of the windows will determine how much natural light and heat a home receives. For example, if a home has large windows on the front façade and you are building on a wide-fronted block, a north-facing block will maximize sunlight. On the other hand, if the main living areas have large windows facing the backyard, a south-facing block will provide a more comfortable living environment.

Deep Blocks and Side Windows

Narrow, but deep blocks present a different set of challenges and opportunities. If the block is deep, you may need to place more windows on the sides of the house to ensure adequate natural light and ventilation. In this case, an east or west-facing block may be the best option. The side windows should ideally primarily face north and give you an opportunity to have a northern courtyard which will be pleasant in summer and winter. 

Challenging Traditional Notions

Traditionally, west-facing blocks are considered the least desirable due to the intense heat from the afternoon sun. However, this orientation can be advantageous if the front façade of your home is largely a garage. The garage can act as a buffer, protecting the living areas from the harshest sunlight and reducing cooling costs. The garage most importantly reduces the area of windows facing west and hence reduces the building cost required to keep the summer heat out.

Maximizing Comfort and Efficiency

By carefully considering the orientation of the house and windows, you can maximize comfort and efficiency. A well-oriented home will take advantage of natural light, reduce reliance on artificial heating and cooling and create a more pleasant living environment.

Reducing Construction Costs

Choosing the right orientation can also help reduce construction costs. Properly oriented homes require lower cost windows and window treatments, costing less to construct a 7-star home This can lead to significant savings during the construction process and greater comfort and more light in the home.

Conclusion

In conclusion, while north-facing homes are often idealized, the best orientation for your house in Adelaide is not a one-size-fits-all solution. It depends on the shape of your block, the type of home you want to build, and the placement of your windows. By thoughtfully considering these factors, you can create a home that is comfortable, efficient, and cost-effective. Whether you have a wide-fronted block, a deep block, or a narrow block, there is an optimal orientation that will suit your needs and preferences. Embrace the flexibility and design a home that truly works for you and your lifestyle.
To find out how I can help you cost effectively achieve a 7-star energy rating go to Architect and Builder Services. or Contact us
]]><![CDATA[Free White Paper]]>Thu, 12 Oct 2023 04:09:46 GMThttps://www.lowenergyhome.com.au/ncc-blog/free-white-paper

Leveraging Energy Advisors for South Australian Builders: A Strategic Approach to Meeting 7-Star Home Requirements

Get your free white paper and ensure you are one of the builders or architects who are ahead of the game and come out of the changes more profitable, not less profitable.
Sign up for our NCC 2022 newsletter and get the white paper.
]]><![CDATA[Building Green can be affordable]]>Sat, 07 Oct 2023 03:20:08 GMThttps://www.lowenergyhome.com.au/ncc-blog/building-green-can-be-affordable
Installation of expanded polystyrene insulation
Use of rendered expanded polystyrene insulation can very cost effectively meet 7-star building requirements.
Claims by the South Australian Housing Industry Association that costs of 7-star homes are $40,000 more than 6-star are simply untrue with appropriate design.

A large six-star home, facing the wrong way (likely a four-star home design tweaked to become six stars) upgraded with the first solution thought of, could cost $40,000, although with optimisation I could significantly reduce the cost.

Starting from a blank sheet of paper and designing from the ground up as a seven-star home the cost increase would be less than the government’s estimate of $10,000. The Australian Glass & Window Association has shown the cost averages $4,300. In many cases with careful consideration, starting at the purchase of the block, considering window orientation, form of the building and changed material selections, a home can be built for the same cost as before.

Some features with high energy demands were cheap to build with the old code, but now are more expensive, while other attractive features cost the same now as before. The trick is to design with the attractive features that are inexpensive but avoid the expensive features.

There is even the opportunity to add some marketing features that will be exceptionally low cost, given the improved building performance.

Even with high interest rates, the savings in running costs will be less than the interest on the extra loan for an intelligently designed home. 

To find out how to cost effectively achieve a 7-star energy rating go to Architect and Builder Services.
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