American’s have long preferred interior shades like drapes and blinds to exterior ones. In Europe, however, that’s not entirely the case. Largely because of their much higher energy costs, Europeans have discovered that exterior window coverings are just as, if not more, effective at blocking out the sun. In fact, devices like retractable awnings, sun screens, and roller shutters have shown to provide significantly more energy savings, and have since become a popular choice for shading European homes and businesses. 

In this informative post, learn the science behind why exterior shades can outperform interior ones, and find out why you may want to reconsider what products you use to shade your home.

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The Energy Trap: Why Exterior Shades Can Outperform Interior Shades

When it comes to understanding the advantages of exterior shading devices, it’s helpful to first understand how the sun’s energy enters your home in the form of heat. Simply put, the sun’s solar energy (or radiation) enters your home’s roof, walls, and windows in the form of two different wavelengths. Shortwave radiation is what heats your home in the form of direct sunlight. Longwave radiation (also known as “convection”) is heat that’s transmitted through the air and by the reflection of the sun’s rays. It’s a weaker source of heat compared to shortwave radiation, but it still accounts for some. 

Now, here’s the key point: when sunlight hits your home, your roof, walls, and windows will stop the longwave radiation, but can do little to shade your home from shortwave radiation, which contributes the bulk of the sun’s heat. Moreover, once the shortwave radiation passes through your home, it can also make contact with your floors, furniture or upholstery. This can cause the heat to then be absorbed and converted into long-wave radiation, trapping the heat inside your home, often to detrimental effect. As the sun’s heat continues to enter your home, your house can get warmer and warmer, straining your air conditioner in the process. 

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How Exterior Shades Can Block Short Wave Radiation

Exterior Shades have long been a popular choice in many European countries for their superior heat-blocking benefits. Here’s why: Exterior shades can absorb nearly all shortwave radiation, effectively “taking the hit” of the sun’s heat. This means that exterior shades can block shortwave radiation from even entering your home, as well as the absorption and conversion of shortwave to longwave heat inside it. 

As many European countries have discovered, this translates to much more comfortable homes on bright sunny days and significantly less energy-costs. In fact, a study done in Trappes France found that exterior shades placed outside a room with no air-conditioning could produce a whopping 15-degree difference compared to the same room with an indoor screen installed. Fortunately, the United States appears to be quickly catching on, with the U.S. Department of Energy recently confirming that exterior window coverings are considerably effective at reducing solar heat gain. 

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What About Interior Shades?

While interior shades can block both shortwave and longwave radiation, they can’t block out shortwave radiation in the same way that exterior solar shades do. That’s because while exterior shades can halt shortwave radiation before it enters your home, interior shades simply absorb the heat from inside it. This absorption is what converts direct sunlight into longwave radiation, effectively trapping heat inside your home.

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Get Your Exterior Shades from Hartley Window Coverings!

Intrigued by the energy-saving benefits of exterior shading products but not sure which one to get? You’ll be happy to know that you can consider all of them! Whether it’s an awning, solar screen, skylight cover, or rolling shutter, almost any exterior shading product will effectively stop shortwave radiation from making contact with your homes’ windows or walls. And, best of all, we provide all of them!

At Hartley Window Coverings, we’re experts in California sun control, and have a wide selection of exterior shading products to choose from. Our products are made with the highest quality materials, backed by many of the best warranties in the industry, and can be installed by our in-house team of professional shade installers. 

Contact us today to learn more about fantastic selection of exterior shading products and discover how they help you stay cool and comfortable all summer long!