Review and Critical Analysis of International UHI Studies

� Costs associated with the generation, collation and presentation of the information.
5.5.4.3 Technological Barriers/Catalyst
The five A’s are now examined to identify the barriers associated with the UHI technologies.
Availability: this examines the status, existence and level of maturity of UHI technology
including whether it has been fully tested and developed. This should also consider whether all
the required materials and tools are available for the mass manufacture of the technology. The
key technologies being discussed were: green roofs, shade trees, cool roofs and cool pavements.
The literature indicates that all (apart from cool pavements) technologies had reached maturity
and thus were readily available. Cool pavements, however, were demonstrated to still require
further research and development to overcome technical issues highlighted in chapter 4.4.2.
Awareness: this component examines the key stakeholders’ knowledge of the UHI technology,
performance benefits and what issues may prevent them from becoming informed. For example
the labeling of roofing materials and cool paints. The literature demonstrates that there is a
general awareness of technology existence however, when the stakeholders make decisions it is
often difficult to know what UHI sensitive alternatives exist and clearer labeling was mentioned
to help differentiate their relative benefits and often justify the higher initial purchase cost over
traditional alternatives.
Accessibility: it is important that once stakeholders are aware of the key UHI technologies and
their existence that they have access to the source of suppliers of UHI mitigating technologies and
materials across the entire supply chain. For example, if a state intends to launch a mass retrofit
of roofs on public buildings it must have access the appropriate materials to undertake the task.
The literature didn’t comment on any supply chain issues; however, in any mass scale up it is
important that the materials and equipment used can be sourced locally to avoid supply chain
bottlenecks.
Affordability: the price of the UHI technology is a vital component for the mass uptake of UHI
technologies. The literature indicated the importance of examining the life‐cycle costs and in
quantifying the benefits resulting from UHI technologies that would often help outweigh the
high initial costs. The price component was indicated to be dependent upon the performance
level of the UHI technology as well as if the technology was to be retrofitted or installed in new
developments. Moreover, it was indicated that the residential sector would be more sensitive to
the first cost element whereas the commercial sectors were more focused on long‐term issues
such as life‐cycle costs and the payback periods. The cool roof technology was indicated not to
suffer from first cost issues due to similar prices to traditional technologies they sought to replace
whereas cool pavements were demonstrated to be costly and life‐cycle benefits unproven.
Acceptance: the acceptability of UHI technologies depends upon the balance of drawbacks and
benefits, the level of benefits attributed to the UHI technology, price and availability. The
literature for cool roofs reported that their competitive pricing, range of alternatives, and ease of
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