Many Denver CO homeowners sometimes refuse installing or replacing an old roof with metal because they fear it will elevate residential utility costs. Logic tells us that metal is a great conductor of heat and will pass this energy in the house. This was true in the early centuries that used metal roofing -- the same ones whose roofs suffered from rust and short metal roof lifespans. Nowadays, many metal roof heat reduction methods exist, and one of them is to use glass or heat-reflective coating.
How does it work? Glass or heat-reflective coating can bounce off both heat and UV rays outward. Uncoated roofs will absorb these energies especially dark-colored metal roofs. In turn, it achieves significant metal roof heat reduction. National Geographic has a great feature on metal roof heat reduction using glass paint.
Heat-Reflective Coating: Effective Metal Roof Heat Reduction
Scientists have created a glass paint that can bounce sunlight off metal roofs and keep them at air temperature. This is no minor feat. The sun can heat metal surfaces so much that playground slides or stadium bleachers can become too hot to use.
The new paint has another potential upside. Since it’s almost completely inorganic—a mixture of silica, the main ingredient in glass, and silicon rubber—it doesn’t degrade in ultraviolet light and can last much longer than typical polymer-based coatings.
“It’s almost like painting a rock on top of your metal. And this is going to last not tens of years but maybe hundreds of years,” says Jason Benkoski, senior scientist at Johns Hopkins University Applied Physics Laboratory. He presented his team’s work Sunday at a conference of the American Chemical Society in Boston.
Paint, low tech and common, hardly seems an effective tool for helping the environment. Yet several products promise they are. Air Pure Paint can remove indoor pollutants including formaldehyde, and Boysen KNOxOUT can suck smog-causing nitrogen oxide from the atmosphere.
More common is white paint and its increasing, though slightly controversial, use on rooftops. There’s even the White Roof Project, a New York-based advocacy group that says such roofs can reduce a building’s summer energy use 10 percent to 40 percent. (Continued)
In the US, a house with a Passive House Institute certification has recognition for being highly efficient. To receive this award, a Denver CO property must comply with its requirements to use metal roofing as a primary roofing material.
Do you achieve this by using heat-reflective coatings? Indeed, you both achieve excellent metal roof heat reduction, excellent property insulation, and a great foundation if you're saving energy by installing solar panels. Metal Roofing Alliance has a great feature on metal roof heat reduction and overall residential energy efficiency below.
Metal Roof Heat Reduction: Passive House Institute Certification
At the highest rank of energy efficient homes stands the Passive House Institutes Certification. Due to metal roofing’s incredibly efficient solar reflectance and thermal emittance, metal is the ideal roofing material for the construction of a net-zero energy home. Metal roofing is also Passive House ready in several key areas:
- Metal roofs protect their insulation backup better which ensures strong long-term thermal resistance.
- Passive House Certification requires airtight construction which is one of the benefits of the inherent air barrier quality of metal panels.
- Metal roofing is a perfect candidate for high efficiency windows and skylights which maintain certification qualities.
Solar energy panels can easily be installed on metal roofs, sometimes even with attachment solutions that do not penetrate the roof system. Since the service life of the metal outlasts the service life of the solar energy system, installations can occur even on existing metal roofs. The ease of installation, roof cooling maximization, and long lasting durability of the metal roofing under your solar panels make solar an easy upgrade for your home with countless benefits.
Apart from the metal roof coating itself, finding the right material will contribute greatly to your metal roof heat reduction efforts. Each metal type has different heat conductivity. In fact, what passes with high electrical conductivity differs from their overall thermal conductivity.
In a simple fourth-grader experiment, Education.com illustrates the thermal conductivity levels of copper, brass, and steel. Read the explanation about the experiments' results below.
Metal Roof Heat Reduction: Thermal Conductivity Experiment Results Explanation
Copper has the highest heat conductivity value, while steel has the lowest heat conductivity value. Heat conductivity is a really important property of a material—we need to keep it in mind when we’re deciding what we’re going to use the material for! Here’s an example: Because copper is such a great conductor, we use it for things like heating rods and wires. Because steel is a poor conductor and can withstand high temperatures, we use it to build engines in airplanes.
Think back to when we folded our wire bridges in half twice. Why do you think we did this? Remember: conduction happens best when more molecules are in contact with each other. Folding the rod in half twice allows the heat from the hot cup to travel through more molecules, allowing more heat to travel from the hot cup to the cold cup. Folding the metal rods only once will still create a good heat bridge, but we would see a smaller temperature change in the cold cups, making it harder to see which metal is the best conductor!
As for the volumes of water needing to be equal? To get good data from our experiment, each hot water cup needs to hold the same amount of heat, and water has a very specific heat capacity. Heat capacity is how much heat energy it takes to change the temperature of a given amount of a substance. Think about it this way: all four of our cups have equal volumes of water at the same temperature, so that means that each hot water cup holds the same amount of heat energy.
So when heat conducts away from the hot cup, does all of that energy go through the metal bridge and into the cold cup? Not at all. Heat is often lost to its surroundings, and in this case, some of the heat from the hot water will be lost to the air. Similarly, the air in the room will lose some of its heat to the cup of cold water. We tried to minimize heat loss by using Styrofoam cups, because Styrofoam is known to be a great insulator—a material that’s a poor conductor of heat. (Continue)
Metal roof heat reduction is simple. With glass or heat-reflective coating, you significantly reduce the thermal conductivity of any metal roofing material. However, to achieve optimal energy efficiency, you'll need the best metal roofers in Denver CO to install your roof. If you have yet to find them, you can call our professionals from Roper Roofing to help you. We have been providing excellent roofing services across Colorado for decades. Call us today!