Decreasing roof temperature which can extend the life of the roof materials (slows degradation).Reducing the pollution and greenhouse gas (GHG) emissions associated with building energy use.Reducing building air conditioning costs and reducing the strain on the electrical grid during peak energy demands.Keeping buildings cooler on hot days to improve indoor comfort and safety.The same basic principles apply to cool walls as to cool roofs.Ĭool roofs have several benefits for both for building owners and the environment. Exterior building walls are exposed to only about half the amount of sun as roofs, but they can also absorb heat.While lighter color roofs tend to have the best SR and TE, new coating and material technologies now exist for other colors that have high SR and TE. An ideal cool roof is a roof with both high solar reflectance (SR) and high thermal emittance (TE). Such a roof is said to have high thermal emittance. Second, a cool roof should also release or emit heat (infrared radiation) so it stays cool. Such a roof is said to have a high solar reflectance. First, a cool roof can reflect away sunlight, so it stays cooler. There are two ways to help cool a roof.Roofs that are lighter in color or are reflective stay cooler than roofs that absorb sunlight. In general, traditional roofs absorb sunlight during the day, heating the building and the surrounding air. A cool roof is made of a material or has a coating that can lower the roof surface temperature, decreasing the amount of heat transferred into a residential or commercial building.This is why the Energy Star label is applied to metal and not to asphalt roofing. You need high emissivity to re-radiate that absorbed heat. Emissivity is of key importance because heat not reflected becomes heat absorbed. With an Energy Star-rated roof product, ‘aged’ means after three years of standardized exposure. The difference between the first and the second is how the shiny and smooth surface degrades to some degree over time-becoming duller and dirtier. “Cool” roof claddings work based on surface properties-1] initial reflectance, 2] “aged” reflectance, and 3] emissivity. because asphalt shingles are so cheap and the profit margin so high. This is why in more technologically advanced countries asphalt roofing is virtually non-existent. Asphalt can’t perform as a quality Energy Star metal roof can over the course of 50 years-which is the lifespan of most metal roofing. It’s lifetime is less than what it’s sold for and replacing it is a dirty job that goes on to break down in a landfill. When comparing to a metal roof, metal is clean and asphalt is a wasteful mess. The Energy Star website notes that roofing material itself isn’t indicative of whether it earns an Energy Star rating, only its measured reflectance. Shingle/shake products simply are not as reflective as the these U.V.
You can find this at the Cool Roof Rating Council, where they list solar reflectivity and thermal emissivity values for hundreds of brands of roofing. And there is a ‘cool roof’ tax credit and a website for approved metal roofs. Metal companies list these ratings under each color. The paint is specifically designed to reflect infrared wavelengths. The secret isn’t in the color of the roofing material but in the paint that our metal manufactures use in the production of your metal roof. light away from your home-this keeps your house cooler in the summer. An asphalt roof will absorb and hold heat where a metal roof will reflect the heat from U.V. A Metal Roof is the most energy efficient roof you can purchase.
0 kommentar(er)
