Americans spend around $40 billion per year to air condition buildings – one-sixth of all of the electricity that this country generates. Cool roofs have been designed so less heat is absorbed and more sunlight is reflected compared to standard roofs. Also, cool roofs are often made out of a highly reflective kind of paint, highly reflective shingles or tiles, or a sheet covering. A cool roof can be beneficial for almost any kind of building, but before you install one consider other factors like climate.
Just like wearing light-colored clothes can help to keep you cool on a hot sunny day, materials used in cool roofs are designed to absorb less heat and reflect more sunlight compared to standard roofs. In the summer sun, dark or standard roofs can reach temperature up to 150 degrees F or higher. Cool roofs under identical conditions can stay over 50 degrees cooler and help you save money and energy by using your air conditioning less.
You can create the cool roof effect on your commercial metal roofing by having it re-coated with a reflective material that reflects the suns light and heat, thereby cooling the area covered beneath it.
Metal Roof Coating Benefits
Cool roofs can benefit buildings and their occupants by:
– Reduce roof temperatures. This can extend the service life of the roof.
– Improve the indoor comfort of areas that are not air-conditioned, like covered patios or garages.
– Decrease energy bills by reducing air conditioning needs.
Cool roofs not only benefit buildings but help the environment as well, particularly when many buildings in the same community have these roofs. A cool roof can:
– Reduce emissions from power plants, including mercury, nitrous oxides, sulfur dioxide, and carbon dioxide, by reducing the use of cooling energy in buildings
– Reduce peak electricity demand. This can also help to prevent power outages.
– Lower local air temperatures (referred to sometimes as the urban heat island effect)
Metal Roof Coating Properties
A cool roof’s most important characteristic is its high solar reflectance. This helps to reflect heat and sunlight away from a building, to reduce the temperature of the roof. High thermal emittance plays an important role as well, especially in sunny and warm climates. These properties combined help roofs a roof to absorb less heat and to remain 50 to 60 degrees cooler during the summer compared to conventional materials.
Roofing contractors and building owners have been using cool roofing products for over 30 years on residential, industrial, and commercial buildings. They can be installed on a gently sloping roof, like a gently sloping or flat roof that tends to be found on office, industrial, and commercial buildings and also on steep-sloped roofs that many retail and residential buildings use.
Through the ENERGY STAR program, the Department of Energy and the EPA help consumers identify the roofing products that are the most energy-efficient. Building materials that have the ENERGY STAR label are required to meet minimum reliability and solar reflectance criteria.
Based on data from 2016 from over 150 ENERGY STAR partners of cool roof product shipments have grown to now represent over 25 percent of the commercial roof products of these manufacturers and about 10 percent of the residential roof products that they offer.
Costs and Benefits of Metal Roof Re-coating
Cool roofs offer a number of benefits other than the mitigation of the urban heat island, including:
– ENERGY STAR roofing products reflect more of the rays of the sun. That can reduce the surface temperature of a roof by as much as 100F, which decreases how much heat gets transferred into the building.
– ENERGY STAR roof products help to reduce how much air conditioning is needed in a building. This can cause a 10-15 percent reduction in peak cooling demand.
– Although using reflective roofing does have inherent benefits, before choosing a roofing product based on what its expected energy saving is, it is important for consumers to explore what the expected calculated results are. It can be found at rsc.ornl.gov, which is the DOE Roof Savings Calculator website.
– Keep in mind that the Energy Savings you can achieve through the use of reflective roofing greatly depends on building envelope efficiency, building location, climatic conditions, insulation used, and facility design.
During the winter, some of the desired heat gain is deflected by cool roofs. However, in general, cool roofs provide net energy savings, particularly in areas with high electricity prices.
Although costs can vary widely depending on the local circumstances and location, a cool roof coating that is on a low-slope roof may cost you $0.75 to $1.50 per square foot. On the other hand, the cost of single-ply cool roof membranes varies from $1.50 to $3 per square foot. This cost premium on cool roofs as compared to standard roofing materials can range from zero to 5-10 cents per square foot for a majority of products, or 10-29 cents for built-up roofs that have a cool coating that is used instead of an aluminum coating or smooth asphalt.
A study from California discovered that cool roofs offer nearly 50 cents per square foot average annual net savings. The price premium is included in the number for cool roofing products and during the winter increased heating costs in addition to summertime energy savings, reduced material and labor costs over time as a result of the longer lifespans of cool roofs compared to conventional roofs, and savings due to downsizing cooling equipment.
Armadillo Roofing & Exteriors (512) 333-7663 provides commercial metal roof re-coating, commercial metal roof restoration, commercial metal roof repair and commercial metal roof installation services to Austin, Texas and the surrounding Austin area communities.