Solar Metal Roofing – How to Make your Metal Roof work for you!

In this solar roofing guide you will learn about the pros and cons of metal roofing with laminated thin-film PV panels such as the ones manufactured by Uni-Solar Ovonics, or simply UniSolar, which is an Energy Conversion Devices company/brand.

UniSolar thin-film solar panels have been specifically designed to be installed with a standing seam metal roof and have a nominal width of 15.5 inches, which fits perfectly onto a 16″ standing seam panel. With a special butyl adhesive backing, the installation of thin-film solar panels is very simple and fast.

Watch how the the solar metal roof is installed and how free electricity is produced right away:

Benefits of Solar Metal Roofing and Roof-Integrated Solar Systems

Installing a solar metal roof is the most cost effective way to get a lifetime roof together with a solar PV system. The savings come from the fact that the installation of a solar power system is greatly simplified, because there is no need to install the racking system, which is needed to hold your conventional solar panels. This saves you about $1 (one dollar) per watt DC of solar system, and eliminates an additional $0.50 per watt for the installation of the racking system and solar panels. With thin-film solar PV laminates, the installation is reduced to cleaning the inside of the metal roof panels, applying and rolling in the PV laminate and installing the metal roofing panels.


Later, when all the standing seam metal roofing panels have been installed, the solar integrator connects the mom and pop contacts on each solar panel to form one, two or more strings of solar panels, and runs the wiring down to the inverter, which then converts the DC power from solar panels into AC power at 240 volts and feeds the electricity into your home’s power network. All excess electricity is sent into the grid (for grid-tied solar systems), or to your storage batteries (for off-grid systems).

Installation of Solar Metal Roofing

Why use a Roof-Integrated Solar System vs. Conventional Solar Panels?

The main problem associated with general solar PV systems that you can now see on many homes around the country, is the fact that an asphalt shingles roof will fail much sooner than the PV solar panels. When that happens, those homeowners will be faced not only with the re-roofing expense, but also with complete removal re-installation of the solar array. This MUST be performed by both the roofer and the solar integrator, as the roofer alone will 99% of the time screw things up. And bear in mind that a roofing warranty will usually not cover damages to the solar equipment, let alone all the possible short-circuit type situations.

Solar Metal Roof Installation Video:

The additional cost associated with these procedures should be at-least the same as the cost of the new roof itself. Think about it: Electricians unlike roofers have to be licensed. An apprentice electrician needs at-least 4 years of schooling/work experience. This is like an undergraduate degree. A master electrician needs another 4 years. Therefore, electricians usually charge $75-100 per man-hour. You’ll need at least two electricians for this job, which will take a whole day to remove the panels and another day to put them back, if not more.

The math is simple: 2 guys * $75/h * 8 hrs. * 2 days = $2400 plus any possible parts and supplies that may be required. So let’s say it costs you $2500 extra. In some parts of the country that is how much an average 1200 sq. ft. cape house roof will cost to install (materials included).

Thin Film Solar Panel Installation Video:

Metal Roofs vs. Asphalt Shingles

Unlike the very “popular” asphalt shingles, metal roofs are pretty much permanent. They are for the most part manufactured from recycled metals, and when installed by a trained professional, they will not leak for decades.

Metal roofs combined with Renewable Energy technologies can create an ideal, long lasting and affordable solution for residential Solar Electric and Solar Hot Water needs.

Solar electric, hot water and heating

There are other numerous benefits to having a metal roof combined with Solar PV and other renewable energy technologies. When looking at a metal roof vs. asphalt shingles, also consider that a metal roof will save our landfills from getting more shingles dumped there in 10 years or so. With metal, you get a beautiful, permanent roofing solution that you can combined with a solar system, and if you choose to add a Geothermal system, you can design a 100% energy-free home!

Metal Roofing and Rain Water Harvesting

Metal roofing for rainwater harvesting is considered one of the best options for maximum efficiency and potability of the harvested rainwater. In any building, a roof is the major catchment area of rainwater, making the quality of the roofing material highly important. According to scientific research, a metal roof has an estimated efficiency quotient of 0.9 on a scale of zero to one. This is ideal for maximum catchment of rainwater.

It is obvious that rainwater catchment would be higher with smoother surfaces. All types of metal roofing materials, such as galvanized iron, corrugated steel, aluminum, various alloys, etc. provide not only smooth surfaces, but they are also bacteria-resistant. Hence, the harvested rainwater is highly potable. Metal roofing easily meets major criteria required for roofing materials used in catchment of rainwater. These criteria and the effectiveness of metal roofing are listed below.

Metal roof installation:



Durability

The roofing system should withstand the weight of the water even during heavy rains. It should not be affected by the accumulation of water on its surface and last for a longer period. Metal roofing is able to meet these conditions perfectly.

Functional Design

The roof should be easy to fix and maintain. It should not leak during periods of heavy rain and remain strong. The roof should allow accumulated water to flow to the rain water harvesting tank smoothly and easily. The metal roofing is better in this aspect, compared to many other types of materials.

Purity of Water

Since metal roofing is resistant to bacteria, the water collected from rain is generally potable straightaway. Still, bugs, dust, dirt, and debris that accumulate on a metal roof are likely to contaminate the water to a certain extent. Hence, the rainwater harvesting system should have adequate filters and other water purifying techniques to remove these materials from the rain water. It is advisable to clean a metal roof before rains are expected to minimize these problems.



Aesthetics

Metal roofing can be made from various materials, such as galvanized iron, corrugated steel, aluminum, and alloys, and can also be manufactured in various designs, patterns, styles and colors. Consequently, the variations in aesthetics that could be achieved with metal roofing materials can never be obtained with concrete roofing, a major alternative to metal.

Cost Considerations

Metal roofing for rainwater harvesting is among the cheapest roofing materials. In particular, compared to solid concrete roofing, metal is the most cost-effective solution. Additionally, concrete roofing needs to be reinforced and strengthened with water-proofing chemicals and treatments. This increases the cost of concrete roofs even further. The sturdiness and durability of metal roofing materials result in the lowest maintenance cost over several years. Hence, metal roofs are highly cost effective.



Solar PV and cool roofing

Reducing Energy consumption to Maximize Solar PV system efficiency

Part II of solar PV design Guide:

As a rule  of thumb, an average house in the US will need about 5 kW solar system to become self-sufficient and  independent of grid electricity. As another rule of thumb, an average Solar PV system installed in the US is about 2.5 – 3 kW, and you still have to buy about half of your electricity from a local utility company.

Before you start shopping for a Solar PV system, you will need to do some homework, and it is also in your best interest to do the preparations, which will reduce your energy use. As a result, you will need a smaller Photovoltaic System.

On average, every dollar you spend on reducing resources consumption will provide 2 dollars in savings. Things you can and should do to reduce your energy consumption (even if you do not plan to have a solar system installed):



  1. Get small florescent light bulbs – you should have done it a long time ago, as these have been available for years. Benefits include reduction in electricity use by 3 times. Service life of SFB is… well, I have a bunch of them that are 3 years old, and I have not had to replace a single one of them yet. I bought mine for $0.50 each, 4 years ago, from Ann & Hope in Cumberland, RI, and some from Building #19. You should have some similar discount retailers near you.
  2. Replace your inefficient appliances with new Energy Star certified ones. Do your research on energy savings. I calculated that if I replace my old fridge with a $200 new Energy Star fridge, I will recoup its cost in 1 year, as it contributes probably half of my $40 monthly electric bill. You can go to a Sears Appliances Outlet and buy brand new stuff for almost 50%  off in store prices.
  3. Insulate your home! Over 80 percent of homes built before 1960’s do not have any insulation. If you increase your insulation from a 3-r for a standard stick-construction walls with no insulation, to lets say 13-r by having a blown-in insulation installed, you will reduce your heating and cooling bill by 25 to 30 percent. Do the same to your windows. If you still have old, drafty single-pane windows, replace them with at least an Energy Star certified double-pane with Low-E film. the best option is to have a Triple Glazed, 2x Low-E, 2x Argon or Krypton gas premium window, that can go to almost 10-r value. Insulate your doors with weather-stripping. A lot of cold air enters the house through the doors, especially, if there is no second door. If you make your home super-insulated, your heating/cooling bill can be reduced to almost 10% of its original amount. That is a 10 times reduction, for which you pay only once, and it will save you money for years to come!
  4. Install Low-Flow shower heads and 1 gallon per flush toilet. Whether you are a landlord or a homeowner, your water bill has probably skyrocketed in the last couple of years. Mine definitely has gone up 30% in last 3 years.

Have a Cool Roof installed

While most heat loss in the winter occurs through the windows, in the summer, most of the heat gain occurs through your roof. Most homes in the US have an asphalt shingles roof, which is not only bad for the environment, but also contributes 90% of the solar heat gain. Even light-colored asphalt shingles attract solar radiation, transfer it into the attic and also act as thermal mass, by storing most of the heat gained during the day, and keeping your attic steaming hot at night, making the AC work around the clock.



Whether you do or do not plan to have a Solar PV system installed (be it on the roof of your house or a ground-mounted array), your first concern must be to reduce your energy use. This is especially true if you actually plan to have a solar electric system installed. A cool roof can reduce your Cooling cost by 25% or more and can help you trim your solar PV system requirements by as much as 1 kW. At $10 to 12 per watt of solar PV system, you are looking to save $10,000 to 12,000 before any incentives or tax credits.

Choices of Cool Roofing for Residential and Commercial use

A good example of a cool roof would be a Metal Roof coated with Kynar 500 Cool-Roof certified reflective coating. You have a variety of architectural styles and choices of metal available to you. From Standing Seam to Aluminum shingles, to Steel Slate or Tile impression to Heavy Cedar shake, Spanish Tile, etc. As for material, your two basic choices are Steel and Aluminum, with Zinc and Copper being the more exotic, as well as the more expensive options. If you are looking to integrate Uni-Solar Thin Film laminates to Standing Seam metal roofing, you want to go with a steel panel, as aluminum’s expansion/contraction ratio is more than that of Uni-Solar’s PV modules.

If you own a home or building with a low pitch or a flat roof, the most economical and greenest choice for you is to use a IB CPA/PVC single-ply membrane, which has a Cool roof acrylic coating, featuring over 90% solar reflectance. IB roof is also a long lasting membrane that features hot-air welded seams. The welded seams create a permanent bond between two sheets of membrane, effectively eliminating the possibility of a leak.

Planning a Solar PV system

Solar electricity is probably the most expensive form of electricity, yet it is very popular due to some constraints associated with other forms of renewable energy. Wind power for example requires an adequate amount of land and the turbine must be located above the trees and surrounding structures. This limits the use of wind turbines mostly to rural areas. Small hydro-electric systems require a water stream or a river near your house or building, which also limits its use to certain locations. Solar on the other hand can be installed almost everywhere, as long as there is unshaded southern exposure and an adequate installation area. Solar PV can be installed on the ground, on the roof of a house, barn/garage, skyscraper or a warehouse. It can be installed in an urban environment – grid-tied, as well as on a remote unpopulated island – off-grid.