Cool Homes

Homes that can stay within a safe temperature range are critical for human health and wellbeing. To reduce reliance on air conditioning as a cooling solution, Cool Homes Credits promote passive design principles to make homes more resilient to high outdoor temperatures and potential power outages during extreme heat.

Resilience framework for heat - Cool Homes

Measures (credits)	Adapt
	Thrive	Survive
CH1: Site Coverage
CH2: Site Shade
CH3: Site Irrigation
CH4: Passive Cooling
CH5: Cool Roof materials
CH6: Cool and/or Porous Pavements
CH7: Alternative Energy Supply

CH1: Site Coverage

2 default credit points

Outcome

Site cover provides for permeable deep soil areas for shade and evapotranspiration from site landscapes to reduce mean radiant temperatures and air temperatures and improve thermal comfort.

Criteria

Site layout provides the following minimum deep soil area (% of site area)

Detached dwellings:
- Lot areas up to 300m²: 20% deep soil area (minimum dimension 3m)
- Lot areas 300m² to 600m²: 25% deep soil area (minimum dimension 3m)
- Lot areas greater than 600m²: 30% deep soil area (minimum dimension 3m)
Attached dwellings:
- Lot areas up to 150m²: 15% deep soil area (minimum dimension 3m)
- Lot areas 150m² to 300m²: 20% deep soil area (minimum dimension 3m)
- Lot areas greater than 300m²: 25% deep soil area (minimum dimension 3m)
Multi-dwelling housing:
- Lot areas up to 1000m²: 20% deep soil area (minimum dimension 3m)
- Lot areas 1000m² to 3000m²: 25% deep soil area (minimum dimension 3m)
- Lot areas greater than 3000m²: 30% deep soil area (minimum dimension 3m)
Apartments:
- Lot areas up to 650m²: 10% deep soil area (minimum dimension 3m)
- Lot areas 650m² to 1500m²: 15% deep soil area (minimum dimension 3m)
- Lot areas greater than 1500m²: 20% deep soil area (minimum dimension 3m)

Guidance

Site layout should, where practicable, provide for deep soil areas to support tree canopy shade to the eastern and western facades of the dwelling/building.

Site layout (across multiple lots) should seek to achieve larger contiguous private open space areas oriented to channel cooling summer winds.

Evidence Requirements

Site landscape plan showing location and extent of deep soil areas as % of total site (allotment) area.

Science Rationale

Research (36) (16) on the influence of land surface type on air temperatures shows:

Increasing the area of green spaces and tree canopy leads to cooling.
When provided in equal proportions, warming from hard surfaces exceeds cooling from green space.
Open space and tree canopy cover can reduce summer night-time air temperatures.
With reference to Figure UD4-1, effective cooling can only be achieved if the ratio of open space to hard surfaces is 2:1 or greater.

*Figure CH1-1 Predicted changes in mean summer air temperature along a gradient of different surface cover types and tree canopy (Source: Pfautsch, S., Tjoelker, A R. (2020)).*

Related Credits

UD1 - Wind Paths
UD5 - Water Sensitive Urban Design
CH2 - Site Shade
CH3 - Site Irrigation
CH4 - Passive Cooling
CH7 - Porous Pavements

References

(16) Pfautsch, S.’ and Rouillard, S. Benchmarking Heat Across Campbelltown City, New South Wales, 2019.

(36) Pfautsch, S., Tjoelker, A R. The impact of surface cover and tree canopy on air temperature in Western Sydney. s.l. : Western Sydney University, 2020.