The logic behind cool roofing is simple. Light colors reflect light, or solar radiation, while dark colors absorb it. Roofs that reflect light from the sun reduce cooling costs for commercial and residential buildings. The level of “coolness” a roof has depends on two properties: reflectivity, how much of the sun’s rays are reflected from the roof; and emissivity, the ability of a surface to emit energy by radiation. The combination of the two is called the Solar Reflectance Index.
When considering a cool roof for your residence or commercial building, you need to answer a few questions:
- Where is the building located?
- How much insulation is there?
- Is system maintenance being factored into the overall cost?
- What effect will a white surface have on the existing roof?
- Do you want a white roof on your house or building?
You should also think about the building’s design and use. A cool roof may not be necessary if energy savings aren’t available. You must also consider the effects the cool roof may have on surrounding surfaces or buildings that could be exposed to reflective radiation. Some materials in rooftop equipment could be damaged, and occupants in neighboring buildings could also be affected.
Cool roofing offers many benefits, including:
- Increased energy efficiency
- Reduced energy bill
- Longer roof life
- Improved comfort
- Reduced capital cost
Make sure that whatever roof coating you choose is installed or applied with professional guidance. Certain materials may expand and contract at different rates, causing shingles to curl and making the roof susceptible to leaks. Don’t compromise the condition of your roof in order to save money by doing the work yourself.
Cool roofing is just one aspect in energy efficiency. Proper attic ventilation is key! A balanced ventilation system requires no energy to run, reducing energy bills and improving the longevity of the roof. Proper ventilation is also important in the months where moisture accumulates in your attic. Damp insulation can cause mold, mildew and rot, affecting both the interior and exterior of your home. Before sealing attic structures in new construction projects, make sure to ask the contractor about proper ventilation.
When installing ventilation systems, follow these tips to avoid common mistakes:
- Check that intake vents are not covered with insulation or painted closed
- Insert attic insulation baffles in the soffit of intake vents
- Use only one type of exhaust vent on the same roof of a common attic
Don’t overlook the shape of your attic – if left in poor condition it could cost a lot in maintenance later. If you wish to “go green” with your roof, you must have a proper approach from the very beginning is the most effective way to do it!
Courtesy of Roofing Contractor
http://www.roofingcontractor.com/articles/88410-energy-efficiency-from-the-roof-down
