FORREST PASSIVE HOUSE

The Forrest Street, Spotswood project is a high-performance residential build completed in 2023 that achieves the rigorous Passive House Plus certification. With a Treated Floor Area (TFA) of 149.3 m2, the building is engineered to maintain extreme thermal stability in Melbourne's temperate climate.

1. Core Performance Benchmarks

The building's performance is defined by its ability to minimise energy loss while maximising comfort:

• Airtightness: Achieved a verified result of 0.4 ACH, comfortably exceeding the Passive House requirement of .6ACH

  Heating Demand: Calculated at 13 kWh/m2, well below the 15 kWh/m2limit.

  Cooling Demand: Extremely low at 3 kWh/m2

  Overheating Frequency: Controlled to 5.7% of the year (times when indoor temperatures exceed 25 degrees), which is well within the 10% tolerance.

2. The Thermal Envelope (U-values)

The building physics rely on low thermal transmittance (U-values) across all assemblies:

• Roof (Living/Kitchen): Achieved a superior U-value of 0.105 w/m2k using a combination of R7.0 and R2.5 insulation batts.

  External Walls: The primary wall assembly has a u-value of 0.258w/m2k. It features R4.0 batts in a 140mm stud, a woodfibre board, and a dedicated service cavity with an additional R1.0 insulation layer to prevent thermal bridging through electrical and plumbing runs.

  Floor: A suspended timber floor, insulated with 180mm of R5.0 insulation

  Glazing: Utilises Viridian Lightbridge triple glazing with unit U-values ranging from 0.75 to 1.02 w/m2k