Energy Savings and Energy Production from Your Roof
The topic of energy is once again in the news all the time these days. I remember first reading about the “Energy Crisis” in my elementary school Weekly Reader, and it’s still relevant many years later. Back then, we turned our heat down to 55 degrees at night in the winter and no higher than 65 degrees during the day. Today that seems pretty drastic, but we “chilled” and lived with it back then.
About 15 years ago, I said, “If you’re in the roofing business, you’re also in the energy business.” And, with energy still such a big topic today, I stand by that statement. As a roofing manufacturer, we consider ourselves to be in the business of helping homeowners save energy, produce energy, or better yet, both!
Saving Energy and Energy Costs
When our company first produced metal shingles in the 1980s, we heard from customers that their energy bills were going down after installing our products. We didn’t know why, so we contracted the Florida Solar Energy Center to research the thermodynamics of metal roofing. Why would a metal roof reduce energy costs for the structure it protects?
After some comparative studies, we found that our products had the impact of R11 insulation in keeping heat out of a structure and reducing the air conditioning load. As we heard from more homeowners, their summer cooling costs dropped by up to 20% after their metal roof installation. Over the years, we have done additional testing to determine exactly why the cooling reductions occur.
Through this research, we’ve determined the cooling load reductions to be the result of:
- The low thermal mass of metals like aluminum and steel. Heat gained from the sun is quickly dissipated when it goes down or behind a cloud or when a gentle breeze blows. Other roofing materials absorb heat all day and then radiate it into the house at night.
- The integral air gap between the metal and the structure with a stamped metal shingle is highly beneficial. This air gap blocks conductive heat transfer from the roof to the attic.
- The reflective pigments used in our paint system block a large percentage of radiant heat transfer.
- The use of natural convective airflow to move heat from the structure to the outside through attic ventilation.
This energy savings, for most homes, reduces the need for summer air conditioning. If the property owners power their home with solar, it reduces the size of the solar array they need. Back to roofing, the roof is usually the ideal location on a property to harness solar power.
Getting solar panels up as high as possible helps them avoid shadows that cut energy production. It also keeps them from potential damage and allows them to be angled for maximum sun exposure.
Energy Production from Your Roof
A metal roof provides an excellent base for traditional solar panels. Consider the following:
- Asphalt shingles, the most commonly used roofing material, have an average life expectancy of 17 years. Solar panels are estimated to last for 20 – 25 years or longer. The solar array will outlast the roof it sits on.
- Metal provides a safe, walkable surface for servicing solar panels.
- Metal roofs often have a cooler surface temperature than other roofing materials. This cooler surface can increase the effectiveness and life of solar panels.
- One option for mounting solar panels is clamping them on the ribs of standing seam metal roofs, reducing or even eliminating roof penetrations.
- Solar customers also desire many of the same things that metal roof customers care about – environmental friendliness, added home value, and decreased operating costs.
For property owners thinking about a new roof, considering the impact on energy, is critical. Metal offers benefits both in terms of saving and producing energy. Feel free to contact me if you’d like to discuss the impact on your home.
Todd Miller has spent his entire career in the metal building products manufacturing industry. He is president of Isaiah Industries, an organization recognized as one of the world’s leading metal roofing manufacturers. Todd is currently Vice President of the MRA (Metal Roofing Association) and a Past Chair of MCA (Metal Construction Association). Through his website, he strives to raise the bar on standards and practices to provide property owners with the best possible products for successful roofing projects.
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