Heat Island Effect

Why the Built Environment Matters

As Winston Churchill stated, “We shape our buildings; thereafter they shape us.” Although human and ecological health are significantly impacted by buildings, they are also affected by other aspects of the built environment such as roads and other human-made infrastructure. If you live in an urban area, you may have noticed that temperatures tend to be higher compared to that of rural areas. This is because roads, buildings, and other structures absorb the sun’s heat, raising temperatures, in what is known as the Heat Island Effect.


Impacts of the Heat Island Effect

The heat island effect is often associated with higher temperatures, however, the impacts of heat island effect are much greater and affect human health, environmental health, and energy consumption. As a result of higher temperatures, the usage of air conditioners and other cooling systems increases, subsequently creating a higher energy demand

Unfortunately, a higher energy demand is usually met using non-renewable sources of energy which leads to an increase in greenhouse gases and pollutants being released into the atmosphere. This creates a positive feedback loop since greenhouse gases retain the sun’s energy and drive temperatures up, creating even more discomfort.

Occupants living in heat islands are more susceptible to heat-related illnesses such as heat stroke, respiratory problems, and general discomfort. It should be no surprise that the distribution of heat illnesses are disproportionate and are more likely to affect children, older adults, and those with existing health conditions. 


Heat Islands Today

It is becoming increasingly common to hear about power outages and system failures occurring due to there being too high of an energy demand. A simple internet search of heat islands brings up current issues of heat islands occurring throughout the United States including Washington D.C., Kansas, and California. 

Learn more and view heat islands with this interactive map.


How To Mitigate the Heat Island Effect

Sustainable building practices are designed to help minimize the impacts of the heat island effect. One method used to address the heat island effect is green roofing. Green roofing is the process of designing a roof to incorporate vegetation, either fully or partially covered. Benefits of having a green roof include: 

  • Lowering air temperatures
  • Absorbing rainwater
  • Supporting wildlife
  • Sequestering carbon

Green roofing unfortunately is not always the best option for some projects. Those who rent or lease an apartment or house, and are not able to make these significant changes, can still landscape in lieu of green-roofing. Planting in pots, maintaining a garden bed at a community garden, and supporting  non-profits that help grow local urban forests, such as Tree San Diego, are great alternatives to helping improve air quality and overall comfort.  

Another sustainable building practice which helps mitigate the heat island effect is building structures using materials with a high Solar Reflectance Index (SRI). SRI is a measurement of how effective a material is at reflecting solar radiance. The higher the SRI of a material, the more effective it is. Benefits of constructing buildings with high SRI materials include:

  • Energy savings
  • Increased occupant comfort
  • Mitigating the heat island effect

In hot and arid regions, such as San Diego, using materials with a high SRI is especially important because it lessens the demand on HVAC systems which consequently reduces energy consumption and the amount of GHGs and pollutants released into the atmosphere. Furthermore, it's also important to ensure energy is being used as efficiently as possible. Whether it is through newer more efficient technologies such as induction cooktops or appliances that are Energy Star certified, reducing energy consumption is beneficial for people, planet, and profit. 


The San Diego Green Building Council is committed to inspiring, educating, and collaborating with the community on issues that affect human and ecological health such as the heat island effect. Our Electric Home Cooktop Program, helps address residential energy consumption as well as providing health benefits such as improved indoor air quality.

To learn more about the Electric Home Cooktop Program or participate please visit the Electric Home Cooktop Program (EHCP) Website. You can also find more information on the energy efficiency of induction cooktops by visiting the EHCP resources section.

Please check your e-mail for a link to activate your account.