In general, light colors reflect the sun's rays, while dark colors absorb heat. Therefore, lighter colored ceilings will divert more heat away from the house and help keep the interior cooler. The opposite is also true: the darker the ceiling, the higher the temperatures on the roof or on the upper floors. White or light-colored ceilings reflect the sun's heat rays, keeping the attic and downstairs rooms cool during warm weather.
As a result, the building's cooling load decreases, helping homeowners and businesses stay comfortable and save money on their energy bills. Because dark roofs absorb more heat, they have a reputation for helping snow melt. This notion is another reason why dark roofs are still popular in northern areas such as the Twin Cities. But do dark roofs really help snow melt? Probably not as much as you think.
The final answer? Light roofs are the most energy efficient roof color for summer, but remember that it's not just the roof color here that comes into play. Other factors, such as roof material, insulation, and roof integrity and age, come into play. An energy efficient roof is one that understands the climate you are in and uses the best materials in your system to reduce overall energy use and keep you warm or cool. What is the most energy efficient roof color? It's white, or a light shade, if you live in an area that experiences hot months.
It's a darker color if you live in an area that has a cold climate and your home craves warmth. Darker shingles absorb more heat, this is true. In summer, a darker roof will measure more heat than a roof with lighter colored tiles. However, if you place a thermometer on both roofs in the middle of a South Carolina summer, both would exceed temperatures of 120 to 140 degrees.
No tile in a 90-degree climate is going to be “cool”, regardless of its color. A cool roof has a lighter color, one that moves away from the traditional midnight black asphalt or dark wood tile styles that have been popular for so long. Your roof has a significant impact on the temperature inside the building, and a dark roof is more likely to conduct a warmer temperature in the structure below, increasing cooling efforts, such as air conditioning. Industry partners have now manufactured more than 50 prototypes of cold shingles, 30 tile and tile coverings, and 20 prototypes of metal panels, including an 18 percent reflective cold black tile, well above the reflectance of 4 percent of conventional black shingles.
Dark roofs are great for absorbing heat, which is very practical if you live in a cold winter climate and your main goal is to keep the heat INSIDE during the colder months of the year. And with metal roof panels, while at first glance a cool brown and a standard brown may appear almost the same color, cold brown is almost 20 percent more reflective of sunlight than conventional brown (27 percent vs. 8 percent). Lighter-colored ceilings generally reflect the sun's heat rays, but dark-colored ceilings absorb much of that heat and transfer it to the rooms below.
In the US, the temperature in your attic at the height of summer can vary up to 50 degrees depending on the material you choose for your roof. At Oak Ridge National Laboratory, Cool Color Roofing Materials Are Tested with the Envelope Systems Research Apparatus. Andre Desjarlais, William Miller and Associates Have Installed Representative Cold Roof Materials at Oak Ridge Roof Testing Facility. This means that heat is transferred from the roof to the inside of the attic, which helps heat the house in winter and makes the air conditioner work harder during the summer months.
While material looks and cost are important aspects when deciding on a new roof, there is one aspect you need to consider that you may not have considered. A darker roof may seem beneficial to structures in colder climates, as dark shingles can help melt snow and ice more efficiently. Dark-colored roofs are more prone to damage due to the high level of UV rays absorbed by shingles; this can cause materials to crack, melt, blister, and fade. .
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