At SUHO, we work closely with homeowners and architects to explore sustainable design opportunities that deliver comfortable, healthy, and energy-efficient living environments. This project involved the retrofit of a single-family home in the Adelaide Hills region, a former 1960s estate given new life through performance-focused upgrades. Our engagement focused on assessing and optimising thermal performance, reducing energy loads, and exploring pathways toward Net Zero energy use while retaining the value of the existing building fabric.
Project Overview
As a retrofit, the home presented typical challenges associated with an older building, including energy losses through external walls, low-performing glazing, and the floor structure. SUHO conducted a Class 1 optimisation assessment, which considered both the existing and proposed building fabric to identify opportunities to improve overall dwelling performance.
Preliminary modelling of existing fabric indicated a significantly higher heating load than the cooling load, a common outcome for older homes in cooler Adelaide Hills climates with minimal insulation, single-glazing, and suspended timber floors. These characteristics highlight the importance of retrofit strategies that improve thermal performance without requiring full reconstruction.
SUHO Recommendations
Through our assessment, SUHO identified key areas to improve performance:
- Ceiling and fixture improvements
- Glazing upgrades
- Insulation enhancements
- Concrete slab improvements
Thermal Performance Outcomes
Optimisation modelling showed that the home’s thermal performance improves substantially with each upgrade. At 7.2 stars, comfortable temperatures (18℃–24℃) are achieved more frequently, reducing reliance on active heating and creating a healthier, more energy-efficient living environment.
Achieving 7+ stars aligns with the National Construction Code requirements, ensuring the home achieves energy-efficiency standards and demonstrating how retrofit projects can meet or exceed new-build performance expectations.
Thermal Comfort Analysis
SUHO’s analysis tracks temperature distributions and frequency throughout the year, highlighting the percentage of time habitable spaces remain within the 18℃–24℃ comfort range. This approach demonstrates how retrofit upgrades can significantly reduce heating demand while improving indoor environmental quality and occupant well-being.
Net Zero Analysis
Within the current NCC 2022 code, NatHERS developed a tool and certificate that includes both a thermal performance star rating and a whole-of-home rating. This whole-of-home rating combines thermal performance with energy use from appliances, as well as energy generation and storage.
For this retrofit project, the comparison was made between a standard whole-of-home appliance assumption and an all-electric whole-of-home appliance assumption, providing insight into how appliance choices influence overall energy performance, operational costs, and emissions. This assessment helps homeowners understand their home’s total energy profile and supports informed decisions that improve comfort while reducing energy bills.
From here, when a project is ready, SUHO can provide the maximum hourly heating and cooling kW demand to assist in HVAC system sizing, estimation, and cost planning.
SUHO Impact
This retrofit demonstrates how existing homes can be transformed through targeted performance upgrades rather than cosmetic renovation. By focusing on measurable improvements, such as insulation, glazing, electrification readiness, and building fabric optimisation, SUHO supported the creation of a healthier, more comfortable, and future-ready home.
Through this Class 1 optimisation, SUHO delivered clear, actionable strategies to improve thermal comfort and reduce energy demand, showcasing the value of retrofitting as a pathway to Net Zero outcomes.
