Review and Critical Analysis of International UHI Studies

� Preparation: Substantial preparation is needed to the surface before the paint can be
applied [238].
� Aesthetics: Given the choice homeowners and building owners typically prefer a darker
colored roof [238].
� Knowledge and Enforcement of Building Codes: Lack of knowledge and enforcement of
the Title 24 reflectivity requirements in California inhibits their full deployment [238].
� Funding: Another barrier to rolling out these approaches in a retrofit market is funding.
Akbari et al suggest selling albedo‐based offsets into the carbon market as a means of
funding UHI mitigation projects, this has never been done before and provides a good
alternative to making lengthy building code revisions [201].
� Time: A drawback of using building codes to implement roof products is the time the
codes take to implement, it can sometimes take over 10 years.
Scale and Magnitude
In the US national model codes and standards exist for cool roofs as well as green building
programs and incentive schemes, however they are adopted and enforced at state and municipal
level so take up is fragmented across the country. Outside of the US the technology is not so
widely promoted or implemented but it is considered very likely that it will as a result of the
increasing popularity and demand in the US.
Building codes are an effective way of incorporating cool roofs into new buildings. On a global
scale however, building codes vary significantly from country to country, some having rigorous
processes rolled out on a country by country level, e.g. Europe, and some have a one‐size‐fits‐all
approach for example, The National Building Code of India. This variation could be seen as a
positive in that a variety of strategies can be adopted to promote cool roofs [201], or as a negative
in that it is currently difficult to capture all the policy that exists in the world due to the process
currently being something of a silo. Without information on other policies around the globe it is
hard to build knowledge and understanding of the benefits and pitfalls associated with policy.
Conclusion
The increasing demand for cool roof products in the US fuels technological advancement,
meaning that materials with improved durability and resistance to UV are currently being
developed. It is also expected that synergies will be developed between cool roof technology and
other efficiency measures such as insulation and air spaces under roofing, thus achieving the
maximum benefits for the building. Building codes for sloped roof designs and government
requirements for cool roofs are also expected to increase in the future if current trends continue
[238].
A key message emerging from the paper review was that incremental strategies such as cool
roofing requirements, are easier to incorporate into policy than comprehensive measures and are
a good way of raising awareness of the technology [081]. A mixture of policy and incentive
schemes are the most advisable and appear to get the most favorable results as they capture the
retrofitting market which is easily overlooked as it is harder to enforce and monitor than new
build schemes.
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