Benefits

• Reduces surface temperatures by up to 30°C compared to traditional materials
• Decreases ambient air temperature by 2-4°C in surrounding areas
• Lowers energy consumption for cooling by 10-40%
• Mitigates the urban heat island effect at neighborhood scale
• Improves thermal comfort for pedestrians and residents
• Extends pavement and roofing material lifespans

Types & Applications

• Cool Roofs: White or reflective coatings, tiles, or membranes
• Cool Pavements: Light-colored concrete, reflective asphalt, permeable pavers
• Cool Walls: Light-colored paints, reflective cladding materials
• Retroreflective Materials: Specialized surfaces that reflect light back to its source
• Phase Change Materials: Absorb heat during day and release at night

How It Works

Cool materials leverage two key properties:

• Solar Reflectance (SR): The ability to reflect sunlight, measured on a scale from 0 to 1
• Thermal Emittance (TE): The ability to release absorbed heat, also measured from 0 to 1
• Solar Reflectance Index (SRI): Combined measure (0-100+) where higher values indicate cooler materials

Conventional dark surfaces can reach 65-85°C in summer, while cool materials stay 20-40°C cooler.

Global Examples

• New York City CoolRoofs Program: 10+ million square feet of cool roofs installed
• Los Angeles Cool Streets: Light-colored pavement reducing surface temperatures by 10°F
• Athens, Greece: Cool pavements in public spaces lowering ambient temperatures by 1.5-2°C
• Japan's Cool Road Technology: Water-retaining pavements combined with reflective properties

Implementation Strategies

• New Construction: Incorporate cool materials into design specifications
• Retrofits: Apply cool coatings during routine maintenance
• Policy Approaches: Building codes, rebates, and cool roof ordinances
• Prioritization: Focus on large surfaces with high sun exposure
• Community Involvement: Volunteer cool roof painting programs

Performance & Considerations

Consider potential glare issues, seasonal effectiveness (more effective in summer), and the importance of maintenance to preserve reflectivity over time.