A recent NOAA headline read that July 2021 was the hottest month ever recorded globally. And while today’s calendar announces the beginning of autumn, scorching daytime temperatures in the mid 900’s point to a lengthening duration of summertime highs. Even more concerning, the overnight low temperatures have crept up over the last 25 years, especially in urbanized areas, and they are actually warming faster than daytime temperatures. Hotter summers exacerbate health issues like heat stroke, COPD, asthma, sleep interruption, and even violence. There are also concerns about possible energy grid failures as air conditioners draw more electricity to cool homes for longer periods of time.
While reducing greenhouse gas emissions and sequestering CO2 are key to halting warming temperatures, adapting our built environment is fundamental to minimizing the negative impacts of heat. Well before the ubiquitous presence of air-conditioning, architects and builders designed structures for natural passive cooling, relying on the orientation of windows, airflow and ventilation, cooling water features, and shaded outdoor space. Today, increasing SHADE – all types of shade – is one of the most tangible solutions to heat, and one that can be done as a post-construction improvement.
Increasing tree canopy is the obvious remedy, as temperatures under tree shade can be 10 to 15 degrees cooler than the surrounding environment. Nearly all building development begins with clearing land of trees, only to sparsely add back ornamentals for aesthetics. Building around trees and preserving trees on development sites is costly and challenging, but wholesale clearing should no longer be tolerated in the name of cost and efficiency. Mature trees provide value, including increased property value which can offset the costs associated with preserving a more natural landscape. Trees should also be replanted on existing lots to shade entrances, driveways, sidewalks and yards. So simply planting a few strategically placed trees is very helpful.
Shade can also be created with canopies, awnings, covered patios, and arcades. Homeowners will likely save money and add enjoyment to time spent outdoors by adding a canopy or other shade coverings to facades to shade windows and patio areas. According to the Professional Awning Manufacturers Association, a high-quality awning can reduce solar heat gain between 72-77% for windows and glass doors facing west, saving up to $200 annually in energy costs. That figure is probably higher in Florida. If you can’t install them outside, consider adding new opaque or reflective shades or curtains inside the home. Drawing shades closed in rooms that are not used, or when you leave the house, prevents solar heat gain, reduces energy use, and lowers your electric bill.
At a commercial and urban street-scape scale, providing covered or shaded walkways in front of storefronts is a no-brainer. Coverings also protect from rain and sun, allowing pedestrians to stroll comfortably, lingering and looking through windows at merchandise or the menu and décor of a restaurant. Shade can prevent damage and discoloration of items in the showcase. Areas with contiguous covered arcades attract shoppers and become urban destinations, likely improving sales. And while some people point out that covered areas also attract a homeless population, social welfare problems shouldn’t overshadow the environmental benefits. Copious amount of shade must be incorporated into public parks, playgrounds, and bleachers on sports fields. On a grander scale, solar canopies could potentially shade parking lots. Solar carports could power car dealerships, which consume 18% more energy than typical office buildings. Solar carports allow customers to walk the lots in comfort, even in the rain, and provide cars with protection from hail or a wayward bird.
On rooftops and facades where canopy shading is challenging, cooling can be achieved by coating heat-absorbing surfaces like roofs, walls, asphalt roads, and parking lots in light-reflective materials. Keeping rooftops cooler can be as simple as painting them white, which reflects sunlight. Purdue University engineers recently created the world’s whitest paint, which they claim may dramatically reduce or even eliminate the need for air conditioners. Green roofs and living green walls also minimize heat absorption and help manage rainwater run-off. Blue roof systems include technologies that capture and store rainwater, providing both cooling and water retention benefits.
Climate change will make our region warmer in the years to come. It is imperative to design our homes, buildings and public infrastructure with this in mind. Increasing shade is an easy first step, something many property owners can do today and city officials could easily incorporated into development codes.
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