So you've decided to build a new home - congrats! As you start talking to builders, you'll hear a lot about "building science" and how they use the latest and greatest construction techniques to build you an energy-efficient, high-performance house. But, for most project home builders, building science is more marketing than real science. Don't get me wrong, we've come a long way in residential construction and building science has led to homes that are safer, more comfortable, and more sustainable. But when it comes down to building at scale, most project builders take shortcuts to save time and money.

The building methods they sell you during the sales pitch aren't always what they actually build (is the display home fully insulated yet your specification excludes the same insulation?).

As you choose a builder, go in with open eyes about the difference between building science in theory and building science in practice. Your new home is too important an investment to end up with something that doesn't live up to the hype.

What Is Building Science?

Building science aims to create structurally sound, energy-efficient homes. But for project home builders in Australia, building science isn't always an exact science. Here's why:

Building science relies on established best practices for home construction based on research and field testing. These recommendations consider factors like climate zone, materials used, and building type. Project builders, however, often value speed and cost-effectiveness over implementing all best practices. They may cut corners to meet tight deadlines or control costs.

Building science also depends on high quality workmanship and close attention to detail. Yet project home construction typically involves many subcontractors and tradespeople, making consistency and precision difficult to achieve. Minor mistakes can reduce a home's structural integrity, energy efficiency, and durability.

Perhaps most significantly, building science aims for optimal long term performance, considering how a home will function over decades. But project builders usually focus on the initial sale, constructing homes to meet minimum standards and buyer expectations. They have little incentive to invest in enhancements that may outlast their responsibilities.

Of course, reputable project builders do apply a degree of building science, and homes that grossly neglect best practices are unacceptable. But if you're choosing a project builder, understand that building science won't always drive their decision making. Do thorough research, ask the right questions, and get professional advice to ensure your home is built as scientifically - and sustainably - as possible. With knowledge and vigilance, you can work with your builder to make building science a higher priority.

Common "Building Science" Myths in Project Home Construction

As a first time home owner looking to build, you’ve probably heard a lot about ‘building science’ and how important it is. The truth is, while building science does aim to create energy efficient, sustainable homes, project home builders don’t always apply the latest research.

Common “Building Science” Myths in Project Home Construction

Many project builders promote building science as a selling point, but the reality is often quite different. Here are a few common myths to be aware of:

  • “We use the latest building science.” The field of building science is constantly evolving, but project builders are slow to change practices and adopt new methods. What was considered cutting edge 5-10 years ago may now be outdated.
  • “Our homes are highly energy efficient.” Project builders face tight deadlines and budgets, so they cut corners where they can. Things like insufficient insulation, leaky ductwork, and inadequately sealed attics and basements are common and reduce energy efficiency.
  • “We consider the local climate.” While building science emphasizes designing for your climate zone, project builders frequently use generic plans across multiple regions with little modification. A house design well-suited for one climate may perform poorly in another.

The reality is that for project builders, building science principles often take a back seat to maximizing profits. As an owner, the best way to get a home tailored to your needs and climate is to do thorough research, get multiple opinions, ask lots of questions, and consider custom building. Building science is complex, but understanding the basics will help you make the choices that are right for you.

The Problem With Prescriptive Building Codes

The problem with prescriptive building codes is that they are focused on minimum standards, not best practices. These codes aim to ensure basic health, safety and welfare, but they don’t necessarily encourage high performance or energy efficiency. For project home builders, the temptation is to just build to the minimum standard in order to maximize profits.

Cost Cutting

When bidding on new home construction projects, builders are under pressure to submit the lowest price to win the job. One easy way to cut costs is to only meet the bare minimum requirements of the building code. The home owner may not realize the house isn’t built to a high standard until issues start popping up down the road. Things like poor insulation, leaky ductwork, and subpar ventilation can lead to high energy bills, indoor air quality problems and premature breakdown of materials.

Lack of holistic thinking

Prescriptive codes focus on individual components like insulation levels, window specs and HVAC sizing. They don’t encourage thinking about how all these parts work together as an integrated system. A high-performance home needs to consider moisture management, air sealing, passive solar design, and other factors that interact with each other. When parts are only built to code minimums, it’s unlikely they will function cohesively as an efficient, durable structure.

Difficulty keeping up with technology

Building codes are slow to adopt new materials, systems and methodologies. They can lag 5-10 years behind innovations in the home building industry. Project builders who want to use the latest energy-efficient and sustainable technologies may find their hands tied by outdated codes. It often takes a long time for updates to work their way through the political and review process before making it into the adopted building codes.

In summary, while prescriptive building codes play an important role in setting minimum health and safety standards for home construction, they should not be viewed as a proxy for best practices or high performance building. Home owners looking for an efficient, sustainable new home are better served working with builders who follow advanced building science and high-performance design principles.

How Construction Details Impact Building Performance

The details in how a home is constructed have a huge impact on its performance and energy efficiency. As a homeowner, it’s important to understand how these construction details affect the building science behind your home.


The type of framing used in your home's walls and roof plays an important role in its structural integrity and insulation. Steel framing conducts more heat than timber, while timber framing may require more maintenance. The spacing between studs also impacts insulation - the smaller the spacing, the less heat transfer.


Proper insulation is key to controlling the temperature in your home. Wall and ceiling insulation helps prevent heat gain in summer and heat loss in winter. Insulation with a higher R-value, like wool or polyester, provides better insulation than fiberglass. The installation method also matters - poorly installed insulation won’t achieve its rated R-value.

Windows and doors

The performance of windows, doors, and any openings in the building envelope significantly impacts the energy efficiency of a home. Double or triple-glazed windows with low-emissivity coatings help prevent heat transfer. Well-sealed doors and weatherstripping around openings limit air leakage.


Effective ventilation removes pollutants from the air and controls humidity in the home. Both natural and mechanical ventilation methods should be considered for a well-performing home. Mechanical heat recovery ventilation systems can recover up to 95% of the energy from exhausted air and redistribute it in the home.


Proper waterproofing, like damp-proof membranes and water resistant coatings, helps prevent moisture damage and improves the durability of a home. Water damage can lead to mold growth, structural damage, and reduced insulation performance.

Following building science principles for these critical details will result in an energy efficient, durable, and comfortable home. While project home builders aim to build efficiently, ensuring the best construction methods are used for your home is well worth the investment.

Questions to Ask Your Builder About Thermal Mass, Rain Screens, and Energy Efficiency

When choosing a project builder, it’s important to understand their approach to building science and how energy efficient they aim to make your new home. Ask them questions about the following key areas:

Thermal Mass

Thermal mass refers to materials that absorb and store heat, like concrete, bricks and tiles. Homes with high thermal mass moderate temperature fluctuations and improve comfort. Ask your builder:

  • Will they include materials with high thermal mass, such as concrete floors and brick external walls? These provide insulation and help regulate indoor temperatures.
  • How will they design the home to utilize thermal mass effectively? For example, will living areas be separated from bedrooms to prevent heat transfer at night? Proper design and placement of thermal mass materials is key.

Rain Screens

Rain screens are barriers behind external walls that allow moisture to drain and evaporate, preventing it from seeping into the home. Inquire if your builder will install rain screens, such as:

  • Cavity walls: Two separate walls with an air gap, allowing moisture to run down the outer wall.
  • Ventilated facades: Panels attached to the outside of walls with an air gap behind.
  • Moisture barriers: Waterproof membranes under external walls to divert moisture.

Rain screens, when installed correctly, improve home durability and energy efficiency.

Energy Ratings

Australian homes are given energy efficiency ratings from 0 to 10 stars. Ask your builder:

  • What star rating do they aim for? At minimum, a 6-star home meets basic energy standards. Higher is better.
  • Will they get an independent rating assessment? Some builders self-rate, but independent assessments are more accurate.
  • What energy saving features will they include to achieve that rating? Things like insulation, double glazing, LED lighting, etc.

The more energy efficient the home, the lower your utility costs will be. An independent energy rating gives you confidence in the builder’s claims.


So there you have it. As you embark on the exciting journey of building your first home with a project builder, go in with realistic expectations about the role of building science. While the concepts around energy efficiency, ventilation, and sustainability seem straightforward in theory, the reality of applying them in the controlled chaos of a building site is far from an exact science. The key is finding a reputable builder who understands these principles and aims to implement them as best as possible within the constraints of budgets, timelines, and variable factors on any given day. Rather than getting caught up in the technical details, focus on the end result of a comfortable, well-built home that suits your needs. After all, your new house is for living in, not just analyzing! Trust in the experience and expertise of your builder, ask practical questions, and try not to get distracted by idealistic notions of building science perfection. Your dream home awaits!