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Metal roofing for rain water harvesting is considered one of the best options for maximum efficiency and the potability of the harvested rain water. In any building, the roof is the major catchment area of the rain water. Hence, the material of the roof is very important in proper rain water harvesting. According to scientific research, the metal roof had been estimated to have an efficiency quotient of 0.9 on a scale of zero to one. This is ideal for maximum catchment of rain water.

It would be obvious even to lay persons that rain water 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 rain water is highly potable. Metal roofing for rain water harvesting easily meets the major criteria required for using metals as the roofing materials in catchment of rain water. These criteria and the effectiveness of metal roofing against each criterion are listed hereunder.

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 for rain water harvesting is able to meet these conditions perfectly.

Functional Design

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

Purity of Water

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

Aesthetics

Since the metal roofing for rain water harvesting could be made from various materials like galvanized iron, corrugated steel roofing, aluminum, and alloys, they could be manufactured in various designs, patterns, styles and colors. This would boost not only the functionality of the roof as a powerful rain water harvesting medium but also the aesthetics of the entire building. The variations in aesthetics that could be achieved with metal roofing materials could never be obtained by concrete roofing, the major alternative to metal roofing.

Cost Considerations

Metal roofing for rain water harvesting is among the cheapest roofing materials. In particular, compared to solid concrete roofing, the metal roofing 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 least maintenance cost over several years. Hence, metal roofs are highly cost effective.

Englert Inc is just one of the many metal roofing manufacturers offering integrated metal roofing and water harvesting systems.

From the above features, it is clear that metal roofing for rain water harvesting is the ideal solution.

Reducing Energy consumption to Maximize Solar PV system efficiency

Part II of solar PV design Guide:

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

Before you start shopping for 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, and as a result you will need a smaller Photovoltaic System.

On average, every dollar you spend on reducing resources consumption, will provide 2 dollar 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 long time ago as these have been available for years. Benefits include reduction in electricity use by 3 time. Service life of SFB is… well, i have a bunch of them that are 3 years old, and I have not had to replaced 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 retailer 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 it’s 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. 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 sky-rocketed in the last couple of years. Mine definitely have 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 solar heat gain. Even light-colored asphalt shingle 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 you 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 ground-mounted array), your firs 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 you 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 metal roofing 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 on the exotic side, as well as the more expensive options. If you look 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 ration is more than that of Uni-Solar’s PV modules.

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

Planning a Solar PV system

Solar electricity is probably the most expensive form of electricity, yet it is very popular due to some constrains associated with other forms of renewable energy. Wind power for example requires 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 requires as water stream or a river nearby your house or building, which also limits it’s use to certain situation. Solar on the other hand can be installed almost everywhere, as long as there is unshaded southern exposure and adequate installation area. Solar PV can be installed on the ground, on the roof of a house, barn/garage, sky-scraper or a warehouse. It can be installed in urban environment – grid-tied, as well as on a remote unpopulated island – off-grid.

With Solar you also have a variety of architectural styles, panel types and mounting methods available. Most popular (yet, least efficient) is to mount mono or poly-silicon solar panels right to the asphalt shingles roof, using mounting rails and brackets.

Why we believe that Metal Roof with Solar Panels is the most practical, and sustainable option for residential Solar PV installations?

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

UniSolar thin-film solar panels have been specifically designed to be install with a standing seam metal roof and have a nominal width of 15.5 inches, which fits perfectly into a 16″ standing seam metal roof 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 install and how solar panels start producing free electricity right away:

Solar Metal Roof Installation video:

Benefits of Solar Metal Roofing and roof-integrated solar systems:

Solar metal roofing is the most cost effective way to get a lifetime roof installed together with a solar PV system. The saving comes from the fact the installation of the solar system is greatly simplified, and elimination of the racking system, which holds conventional solar panels, is eliminated. This save you about $1 (one dollar) per watt DC of solar system, and eliminates an additional $.50 per watt for the installation of the racing system and solar panels. With thin-film solar PV laminates, the installation is reduced to cleaning the inside of the metal roof panel, applying and rolling in the solar 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 on, two or more string 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 and all the excess electricity is sent into the grid (for grid-tied solar systems) or to your storage batteries (for off-grid solar systems). You can use solar calculator to estimate the cost of solar system and calculate solar roof price

Why use 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 Solar panels, and when that happens, those home owners will be faced not only with re-roofing expense, but also with complete removal of solar array and re-installation. 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 roofing warranty will usually not cover damages to the solar equipment, let alone all the possible short-circuit type situations.

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. Apprentice electrician needs at-least 4 years of schooling/work experience. This is like an undergraduate degree. 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 today with the material.

Metal Roofs vs. Asphalt shingles

Unlike very “popular” asphalt shingles, metal roofs are pretty much permanent. They are for the most part, produced from recycled metals, and when installed by a trained professional, should not leak for decades. Read more about residential and commercial metal roofing .

Metal roofs combined with Renewable Energy technologies can create a perfect combination of light, long-lasting and affordable solution for Solar Electric and Solar Hot Water, as demonstrated in the image to the below:

There are other numerous benefits to having metal roof combined with Solar PV and other renewable energy technologies. When looking at metal roof vs. asphalt shingles, also consider that metal roof will save our land fills from getting more shingles dumped there in 10 years or so. Combined with beautiful looks, you get a permanent roofing solution, various solar technologies, and when paired up with geo-thermal system, you can easily design a 100% energy-free home, with a great curb-appeal.

Check back in a couple of weeks for a complete Solar Metal Roofing Guide.