A metal roof with built-in solar panels is the most energy efficient and longest lasting solar roofing solution. A metal roof will usually last in excess of 50 years, and solar PV panels usually last 30+ years with minimal loss of efficiency or or electric power production. The combination of the two creates a one-time green roofing investment that will pay for itself over time, and then it will produce free electricity. Such a smart combination eliminates the chance of roof leaks, since there are no roof penetrations, and gives a homeowner piece of mind and confidence in their green metal roof.
Why go with a metal roof, instead of asphalt shingles:
Why would you want to install PV solar panels with a metal roof, instead of installing it on the existing asphalt shingle roof? The answer is very simple; asphalt shingles last an average of 15 years, while your solar panels should last at least 30 years. That means that even if you install your solar panels over a brand new asphalt shingles roof, you will have to remove the whole solar system in 15 years, replace the roof, and then put the solar panels back onto the roof. With the installation costs of a solar PV system being about $2 per watt, and an average solar system size of 3 KW, you will have to pay an extra $6000 (in today’s dollars, before any inflation is calculated) to reinstall your solar panels, and another $1500-2000 to
remove the panels, so that the roof can be replaced. With today’s average solar system price of $9-11 including solar panels, inverter, all wiring, rack-mounting system, permits, installation, etc.), the removal and re-installation price amounts to about 25% of the total solar system cost.
A properly installed standing seam metal roof will easily outlast any asphalt shingles roof by 3 time or more, and it will also outlast a warranty period on any solar panels. When your solar panels get old, and start producing less electricity than what they were designed for, you will have an option to either keep the old solar panels or install the new ones (as a side-note – average efficiency loss of a solar panel is 0.5% per year or 10% over a 20 year warranty period). All your infrastructure will already be in place, and you can simply swap the old solar panels for the new ones. You may also have to swap the charge controller / inverter. In 20 or 30 years, as technology progresses, the efficiency of solar panels and inverters will be much higher, and the cost per watt will be considerably lower. At the same time you will still have your metal roof, performing at 100% efficiency – being leak free and beautiful, that is.
Installing solar panels on a standing seam metal roof
Solar panels can be attached to a standing seam metal roof in two different ways. One is to use a thin film Solar PV panel laminated inside the pan of a standing seam metal roof – a so called solar metal roofing concept, when solar panels are integrated with the roofing material. The limitations of solar metal roofing include lower efficiency (per sq. foot or sq. meter) of the solar PV laminates. Therefore you would need double the roof area to get the same number of kW of a solar system. Also the size limitation of each solar PV laminate (18 feet long panels) make it impossible to install them on roofs with a roof run of less than 18.5 feet.
A better way to install solar panels onto a metal roof is to use S-5 clips or mounting brackets, specially designed to add adequate strength and support of rack-mounting systems installed on standing seam metal roofs. S-5 clops are made of cast aluminum blocks, with stainless steel tightening screws. S-5 clips are attached to the ribs or locks of a standing seam panel, and provide great pullout ratio, meeting and exceeding Miami-Dade county building code requirements for wind uplift.
S-5 Solar Panel mounting clamps allow for a quick and inexpensive installation of the solar rack-mounting system. Solar panels can be attached directly to the clamps, or to horizontal / vertical rails. The overall cost of such solar racking system is reduced from about $1 per watt, to about 50 cents per watt, or less. Also, you do not have to worry about any roof leaks, as there are no roof penetrations, and all mounting hardware is attached to the ribs of the metal roof panels.
You can also get a double tax credit for your solar roofing installation – Your first tax credit would be a 30% tax credit for solar panels, and and another one – up to $1500 cool roof tax credit. An average cost of metal roofing materials will exceed $5000 per roof, so you will be able to get a full 30% cool roof tax credit. With today’s metal roofing prices for steel standing seam ranging from $15000-20000, a $1500 tax credit will save you about 7-10% off your lifetime metal roof.