Climate change and its effect on our population is a significant concern for leaders all over the world. Many cities like New York, Chicago, Denver, and San Francisco have instituted rules for types of roofs that new commercial or residential buildings must install in an effort to help with air quality, wildlife preservation, and energy efficiency. Learn more about the different types as we answer the question: “Do white roofs keep houses cooler?”
What Are Green, Blue, Brown, and White Roofs?
In recent years, scientists, engineers, and architects have made remarkable progress in figuring out how to help clean the air, preserve natural resources, and make more energy-efficient buildings as cities grow.
That’s a particular challenge in dense populations where there is little to no space between buildings other than roads and sidewalks, much less room for trees and plants to grow. When these monolithic structures block out the sun, where can plants flourish? The answer turned out to be on the rooftops. Biodiverse “green” roofs are installed with a substrate and seeds or plants at the time of construction.
“Brown” roofs are installed with the substrate to support plants but are left bare to organically collect and germinate seeds from birds or the wind.
There are many benefits to creating more biodiversity by claiming the roof spaces. They create more beautiful city vistas, allow for food sources from gardens, encourage people to get out of their apartments and enjoy nature, and provide shelter for wildlife. These multi-purpose rooftops also help with air quality and energy efficiency of the buildings. Let’s look at the different types of roofs and the benefits of each before we answer the question: Do white roofs keep houses cooler?
The Green Roof
A green roof can be anything from a thin layer of low-maintenance plants to an elaborate multilayer rooftop garden. They insulate against heat in the summer and cold in the winter. These gardens absorb carbon dioxide and act as a habitat for birds, bees, butterflies, and other wildlife. There is also research to support the positive effects of nature in building design for reducing stress and improving mood, along with reducing the carbon footprint.
The Blue Roof
When you hear the term “blue roof” it may bring to mind the iconic cliffside rooftops of Santorini. In this case, we are referring to a rooftop method of slowing stormwater runoff by holding it in an open area or porous material. These water storage systems can be housed under decking or walkways so the area can still be used as is or combined with green roofs to provide water to the plants. The water retained with blue roofs can be used to flush toilets to reduce water demand and can also help cool the building.
The Brown Roof
Brown roofs may not start out with any plants initially, but they offer benefits from the start. They require little to no water and they slow water runoff. Material that would otherwise be waste, like cleaned building rubble, boulders, or other stones, can be recycled into the substrate and used to attract wildlife. The earth on top of the building insulates against sound, heat, and cold.
The White Roof
A white roof is highly reflective by itself but even more effective at reducing temperatures in the buildings when combined with an additional coating designed to deflect sunlight and minimize heat absorption, known as a cool roof. White roofs can lower the overall energy demand in the building and mitigate the heat island effect, where pockets of higher temperatures form around areas dense with buildings and pavement. White roofs are becoming more important and more common as summer temperatures continue to break records even in areas not known for extreme heat.
Do White Roofs Keep Houses Cooler?
All of these roofing options, green, blue, brown, and white, play a role in energy efficiency. They each provide multiple highly valuable benefits. Green, blue, and brown roofs are beneficial for supporting wildlife as well.
While they do not grow plant life, white-painted roofs do reflect as much as 85% of sunlight, keeping the building cooler and reducing the need for air conditioning. The air temperature around these types of roofs is an average 7 to 8 degrees cooler than the surrounding area, answering the question, “Do white roofs keep houses cooler?” with a definitive yes.
Strengthen Your Company’s ESG Program
ESG Property Consultants helps companies stay competitive in a rapidly evolving business landscape. ESG consulting is our passion and our expertise. To find out more about energy-efficient roof options as well as other ways we can help you with a custom-tailored ESG strategy for your company, contact us today.