When setting up your hot tub, you might focus on details like pad size, electrical standards and spa accessories. However, one often overlooked danger is the potential damage caused by reflective surfaces such as greenhouses, clear-roofed pergolas and windows.
The risk of reflective surfaces
Windows — particularly the new low-energy, heat-reflective ones — can cause significant damage to hot tub siding, vinyl and hardcovers. The harmful reflections from these surfaces can warp and melt the foam inside hot tub covers, often creating distortion or bowing in the shape of the nearby windows.
High temperatures can cause damage
Reflected heat from windows can raise the surface temperature to 175 degrees or higher. While UV inhibitors in hot tub cover materials help protect the cover and particularly the cover color, these extreme temperatures can melt the components, with damage not limited to covers but also extending to cabinets. To avoid this, it’s recommended to install hot tubs at least 20 feet away from windows.
Hot tubs aren’t the only products that are known to be affected. Other outdoor products and even cars, as noted in this story from WSB-TV out of Atlanta, Georgia, can be severely damaged.
Real-life example of reflective damage
Rob Anderson, vice president of Olympic Hot Tub, recalls a customer who experienced melting on their cover after replacing their windows with low-energy panes. Using a heat gun, Anderson measured that the reflection from a second-story window raised the temperature to 270 degrees, melting the hot tub cover. In contrast, the shaded part of the cover was the same temperature as the ambient air, while the portion in the sun but not affected by the reflection was around 130 degrees.
Anderson notes that glass patio lights and other reflective surfaces can also cause damage. Signs of this issue may include odd fading patterns on patio furniture or warping in synthetic decking materials. He advises thinking broadly when diagnosing damage, as reflective surfaces outside the immediate area, such as a neighbor’s yard, can also be culprits.
Often, the problem only becomes visible after the damage has already occurred.
“The sun moves across the sky not only throughout the day but also changes position in the sky throughout the year, which means the angle of the sun changes,” Anderson says. “While a customer may notice damage today and blame the [product] for failing the damage may have actually occurred days, weeks or months ago.”
Prevention and solutions
The simplest solution is to place your hot tub away from harmful reflections, but this isn’t always feasible. Another option is to install a clear, matte-finish UV film on windows or reflective surfaces to block up to 99% of UV rays, reducing damaging reflections while still allowing light into your home.
Anderson advises against using clear plastic coverings, tarps or corrugated roofing materials over your hot tub. Also, remember to check for potential reflective surfaces in your neighbor’s yard that could affect your hot tub.
Key considerations for hot tub placement
When choosing a location for your hot tub, consider the distance from your home, the view, room for accessories and a structurally sound flat surface. Additionally, be mindful of potentially harmful reflective surfaces. This kind of damage is not covered in hot tub or hot tub cover warranties. By being aware of these dangers and taking preventive measures, you can protect your hot tub and enjoy it for years to come.