Your source of information about Photovoltaic (PV) working principles and advanced technologies. This white paper does not address these topics but instead focuses on an often overlooked topic: durability, longevity, and mounting platform compatibility of these systems with roofs. Photovoltaics are not only environmentally friendly, but also a prudent financial investment for both residential and commercial rooftop power. In the continental United States, rooftop solar investments typically have a simple payback period of 3-7 years, after which they will continue to generate electricity for 25 years or more. However, it may not make economic sense to install PV onto a roof that has a shorter lifespan than the PV array.
Metal roofs have inherent aspects that make them the perfect platform for installing photovoltaic systems, including geometry, strength, sustainability and durability against wind, hail, rain and snow. First, metals are highly inert, and service life is measured not in years, but in decades. Given that solar PV has a lifespan of over 30 years and a price tag that far exceeds that of any roof it is installed on, this factor alone drives the wise choice of a metal roof.
Metal is the only roof type that outperforms solar slate, the only exception being natural slate (which is only suitable for steep slope applications and is 5-10 times the cost of metal). Installing PV on most other types of roofs will require roof replacement at the mid-life point of the PV life cycle. Replacement involves removing the PV array and reinstalling it once the roof replacement is complete - maybe even more than once.
Metal roofs come in many different colors, thicknesses and profiles, some of which are more suitable for photovoltaic installations than others. Standing seam profiles provide a significant advantage by providing a penetration-free method of attachment of the array to the roof surface. This profile enables the PV connection to maintain design intent - zero penetration of the roof, thereby maintaining weather integrity and roofing material guarantees throughout the PV lifetime and beyond.
While metal roofing systems may have a higher initial cost than some other roofing materials, the cost of installing a solar array can also be reduced, offsetting the premium cost of the roof. The benefits of metals are even better when analyzing "life cycle" costs. Compiled by Chen Yuanyun
