Photo: Walmart via Flickr
Policy Solution

Cool roofs

Mandate

Overview:

Summary: Cool roofs are designed with materials that reflect more sunlight than conventional roofs, reduce building heat retention, and in turn reduce the urban heat island effect. Cool roofs can reduce internal building temperatures by up to 30%.

Implementation: Update code requirements for construction of new buildings and substantive rehabilitations. These mandates can include building codes or energy codes. Building codes can require a minimum percentage of cool roofs on new buildings.

Considerations for Use: Areas with cold winters will trade-off reduced heat retention during warmer months with increased heating needs and moisture buildup during colder months. Cool roofs work best in areas with uniform building heights. Shorter buildings may cause glare on taller buildings. Depending on the treatment applied, cool roofs lose some surface reflectivity over time. The cost of coating materials will vary based on selected coating and local availability. Integrating cool roofs in new construction is more cost effective than a retrofit, but cool roofs are still one of the most affordable and approachable retrofit measures.

  • Policy Levers: The mechanism municipalities can use to actualize the intervention. These policy levers will likely be used in combination with each other.

    MandateMandates are government regulations that require stakeholders to meet standards through building codes, ordinances, zoning policies, or other regulatory tools.
  • Trigger Points: Opportunities for municipalities to implement risk reduction and preparedness interventions based on the policy lever, building on the United Nations Environment Programme triggers used in the Beating the Heat handbook (2021).

    City planning processesIncludes city initiatives such as the development of climate action plan, pathway to zero-energy, master plan, transit plan, energy mapping etc.
    Introducing new or updated zoning/codesIncludes codes, zoning requirements or by-laws pertaining to urban planning and building construction activity.
    No-regrets actions (low cost/low effort but substantial benefit)Interventions that are relatively low-cost and low effort (in terms of requisite dependencies) but have substantial environmental and/or social benefits.
  • Intervention Type:
    Buildings and Built Form
  • Sectors:
    Buildings,

    Impact:

  • Target Beneficiaries:
    Residents; Property owners; Heat-vulnerable communities
  • Phase of Impact:
    Risk reduction and mitigation
  • Metrics:
    Number of buildings compliant with provision; Energy savings by building; Indoor air temperature reductions; Outdoor ambient air temperature

Implementation:

  • Intervention Scale:
    Building
  • Authority and Governance:
    City government
  • Implementation Timeline:
    Medium-term (3-9 Years)
  • Implementation Stakeholders:
    Array
  • Funding Sources:
    Public investment; Private investment
  • Capacity to Act:
    Medium; High

    Benefits:

  • Cost-Benefit:
    Low
  • Public Good:
    Low
  • GHG Reduction:
    Medium
  • Co-benefits (Climate/Environmental):
    Reduce greenhouse gas emissions
  • Co-benefits (Social):
    Save on utilities; Create jobs