October 22, 2021

PART THREE OF THREE: Having the ‘chat’ with your builder

In this three part series, founder and director of PassivEnergy, Rob Iacono demystifies the questions surrounding energy ratings, sustainable home building and his tips of what to consider when chatting with your builder. Today, Rob discusses why it is so important to constantly check in with your builder about the materials being used within your build, and their associated ratings.

Read part two: 10 must-haves to build a more sustainable home


When I meet someone for the first time and find out that they’re building a home, I like to ask them these 2 questions:

  1. How many double-glazed windows do you have?
  2. What type of insulation do you have?

The answers so far have all been a confused “no idea.” We often know that the kitchen bench top is Caesarstone or that Miele products have been fitted, but the glazing and insulation, which helps immensely in keeping our home comfortable all year round, is often overlooked for the shiny things that we can see and understand. As the saying goes, ‘out of sight, out of mind!’

The underlining truth here is that all new homes built after May 2011 require a mandatory 6-star energy rating to help keep our homes more comfortable year-round, and to reduce our need for mechanical heating and air-conditioning systems, which in turn keeps our quarterly energy bills lower. The materials you and your builder decide to use can impact greatly on the outcome of your star rating.

Unfortunately, a large percentage of homes that we have provided 6-star energy ratings for do not incorporate solar passive design principles, which results in the use of more double glazed windows and thick insulation to meet minimum requirements. That’s not even the worst part! Scarily, our 6-star energy rating reports, which are required by council and form part of the building permit, are often stamped and then hidden away in a file somewhere never to see the light again.

A building surveyor will be required to go out on site for mandatory inspections, one of those is for the frame work and then next one following that is for the occupancy certificate, deeming the home to be liveable.  Checking to see if the correct insulation or windows have been installed is not included in one of these inspections and can therefore be missed.

Sadly, it’s up to the future home owner to make sure the dwelling is being built to the minimum 6-star standard. But don’t panic, we’re here to help!

As part of the 6-star energy rating process, you will receive a report which will list the minimum specifications required to achieve compliance. There are minimum insulation values that are divided into 3 main parts that form the building envelope, the roof, the walls, and the floor.

The glazing will have 2 values that need to be matched, the U-Value and the SHGC value. It will also be noted whether these windows are single glazed or double glazed.

Speaking to your builder during the contracts stage is critical. You will be discussing a lot of things with the builder before you sign a contract, including what appliances you want installed, cabinetry styles, wall colours, cladding etc. It at this moment that you can also discuss what the energy rating requirements are to achieve the minimum 6 stars.

Insulation values and where they are required is paramount, as is the window requirements. I was shocked when I once received a call regarding energy efficient lighting and fixtures, to then discover the builder had installed all single glazed windows, when double glazed windows were nominated for the living and bedroom areas. It certainly happens, a lot more than you think.

Don’t be afraid to be in constant talks with your builder throughout the construction of your home. Once the frame is up and insulation has been installed, ask to inspect it to ensure the correct R-Value has been used and whether any gaps have been left. Gaps can be a real problem causing air to leak in and out of the building at free will, so it is important to ensure whatever insulation product is used, that it is cut to fit perfectly between all stud frames and services.

Ask to see the window data from the window manufacture’s specification sheet. Ensure that the windows specified as double glazing in the 6-star energy rating report have been ordered and built on site accordingly, and that the appropriate sealing has been used. Some window manufacturers are now asking for the energy rating report to feature their codes so that they can properly quote the window requirements, this is a good step in the right direction and will give the owners a better chance of having the correct windows installed.

Building a home is one of the biggest investments you have in life, whether it is your forever home or a home that you will have until you outgrow it. Getting the energy efficiency requirements built to at least the minimum 6 star standard will ensure that you are helping your home stay comfortable all year round and save a few dollars in energy costs. It is highly beneficial to be proactive about your homes energy efficiency.

Have more questions? If you’d like to work with me then get in touch today, let’s get you started on the right path!


Rob Iacono is the founder of Passivenergy, he has a background in architectural building design and sustainable design and is passionate about educating his clients on the importance of energy efficient homes and passive design principles.

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Efficient, cost effective sustainability (ESD) reports for building and planning permits.