Energy Efficiency on the She Renovates Podcast
“Unlock the secrets to creating comfortable, sustainable homes without breaking the bank!
Join us as we delve into the world of Passive House design with Audrey Whisker, director of Whisker Architecture.
Discover practical tips to save on time, money, and energy bills while transforming your space into a cozy haven.
From DIY insulation hacks to maximizing natural light, Audrey shares invaluable insights to elevate your home's efficiency.
Don't miss out on this episode of She Renovates, where we bridge the gap between profitability and purposeful living.
Tune in now!” - She Renovates Podcast
Archive note: This page preserves a 2024 podcast conversation. For Whisker Architecture’s current approach to comfortable, efficient homes—including passive-design thinking, right-sizing, reuse and careful material choices—see Sustainable Architecture.
Passive House or PassivHaus - It's a great option for your home.
Current reading notes — reviewed 5 October 2026
The recording above preserves a 2024 conversation. These revised written notes explain the design decisions we would discuss today; they supersede the earlier show notes rather than reproducing the interview word for word.
Start with the house and the people
A comfortable home starts with understanding its orientation, shading, insulation, windows, unwanted air leakage and ventilation. Existing buildings need an assessment of their condition and practical upgrade opportunities before choosing a package of works. A star rating, a comfortable temperature range or an energy-saving percentage is not a guarantee of an individual household’s experience or bills.
The earlier notes quoted population-level mortality figures. Those figures do not establish how many deaths were caused by inadequate insulation, and we have removed that attribution. This article offers architectural guidance, not medical advice.
Passive design and certified Passive House
Passive design uses the site, climate, sun and building envelope to reduce heating and cooling demand. Certified Passive House is a defined performance standard that requires appropriate modelling, documentation, testing and independent certification. A home using passive-solar principles is not automatically a certified Passive House, and heating or cooling may still be needed.
For existing buildings, the Passive House Institute’s EnerPHit pathway addresses retrofit conditions through its own requirements. If certification is part of your brief, agree the target, specialist team and verification process at the outset. Whisker’s past Passive House training informs our design thinking; it is not a claim of current designer certification.
Plan upgrades together
Insulation, glazing, shading, draught sealing, efficient equipment and ventilation work as a system. Improve the weakest parts in an order that fits the building, budget and future renovation. Seek advice on insulation installation, electrical safety, combustion appliances, moisture and any hazardous materials before starting work.
Do not block required ventilation or seal combustion-appliance openings as a DIY shortcut. Airtightness and ventilation need coordinated design. An air-change result must identify its test conditions; “5 ACH” alone does not create a universal requirement to install heat-recovery ventilation. The applicable building requirements and ventilation solution must be assessed for the project.
Compare costs and benefits for your project
A modelled rating describes an assessment under stated assumptions. It does not measure actual household energy use or establish a universal payback period. Heating and cooling demand is also different from total household energy consumption. The earlier “up to 90%” total-energy claim has been removed.
Upgrade costs, savings and priorities depend on the existing house, climate, equipment, use patterns, energy prices and scope. Historical case studies can help explain a decision, but their prices and outcomes should not be treated as a current quote or a promise for another home.
For current building-code requirements, confirm the building class, approval timing, applicable provisions and any transition arrangements with your building surveyor and energy assessor. The interview’s 2024 adoption reference should not be read as a single rule covering every new building or renovation.
Historical modelling example from the 2024 conversation: The figures below compare design options for one existing home. They are modelled star-rating results under that assessment’s assumptions, not measured bills, current prices or a prediction for another property.
Renovation Case Study
Existing Home: 2.2 stars
Option 1 - Star rating: 4.3 stars
- R6.0 to the ceiling
- No insulation to walls / floor
- Timber windows to North and South, uPVC to remainder
Option 2 - Star rating: 4.6 stars
- R6.0 to the ceiling
- R2.5 to the floor
- No insulation to walls
- Timber windows to North and South, uPVC to remainder
Option 3 - Star rating: 6.7 stars
- R6.0 to the ceiling
- No insulation to the floors
- R2.5 to walls
- Timber windows to North and South, uPVC to remainder
Option 4 - Star rating: 7.2 stars
- R6.0 to the ceiling
- R2.5 to the floor
- R2.5 to walls (e.g. https://enviroflex.com.au/wall-insulation/ )
- Timber windows to North and South, uPVC to remainder
For this project we chose to proceed with Option 3 as there wasn’t enough room under the floor to install insulation.
Explore current guidance and relevant projects
Read the Australian Government’s insulation guidance and ventilation and airtightness guidance, or the Passive House Institute’s explanation of the standard.
See our sustainable architecture approach and how an existing footprint was reconsidered at Banksia Renewed in Wonga Park. Planning a larger upgrade? Our renovation service and Home Masterplan Report can help you compare scope, priorities and early cost guidance before committing to a design direction.
