Energy Efficient Reflective Roof Products

Energy efficient reflective roof products reflect the sun’s rays and thereby significantly reduce roof surface temperatures. This transfer of solar heat back into the atmosphere correspondingly decreases the transfer of heat into a building that would otherwise occur and it offers building owners numerous advantages, including:

• Reduced energy usage and bills (by as much as 50 percent) from reduced air conditioning requirements.
• Reduced peak cooling demand (approximately 15 percent), because a smaller, more efficient and less expensive cooling systems are needed to condition the building.
• Reduced emissions as a result of reduced energy usage

Properly designed reflective roof products also typically extend the life of a roof by reducing the thermal shock the roof experiences through its normal life. Thermal shock occurs, for example, when cool rain hits a hot roof leading to stress and degradation of a roof. This  improvement is due primarily to more constant roof temperatures.

Key Attributes of Energy Efficient Reflective Roof Products

There are two major variables that determine the extent to which roof products contribute to energy savings:

• Solar reflectancedetermines the extent to which a roof product efficiently reflects sunlight and heat away from a building and hereby reducing roof temperature.
• Emissivity refers to a material’s ability to release absorbed heat. Given the local climate, a residential customer may want either high (greater than 85 percent) emissivity in warmer climates where reducing the cooling load is desired or low emissivity in cooler climates where retaining heat/reducing heating load is desired.

Though not generally included in specifications for roof installation, roof insulation is also an important contributor to reducing energy consumption, particularly in the colder climates. Measured by R-value (a higher R-value translates to less heat loss), one can refer to the International Energy Conservation Code to determine the best insulation for a given location.

The time period preceding initial building design or when the existing roof requires repair are the optimal times for upgrading roof materials to achieve these benefits.

Click here for basic introduction to solar power.