Energy Efficient Roofing

Whether you’re a new home builder or your current roof is starting to look like it needs repairs and perhaps a full replacement, you might be rewarded with huge energy savings, if you’re living in warm climates, by selecting an energy efficient roofing option. You’ll also be helping to keep the environment healthy too.

Another term used to describe energy efficient roofing is “Cool Roofs” and “Cool Roofing”, this is because of its capacity to reduce the temperatures of the structure below it. Cool roofing can effectively reduce the costs of energy applied to keeping buildings cool by cutting down on your AC use. But how could a roof which is quite a simplistic device, be such an energy efficient part of a building?

Cool-Roofing-graphic

image credit: coolroofs.org

Lets look further into the vital function that roofing plays in the protection of the building. Roofing is the part of the building that acts as a shield from the elements bearing down from above, most importantly the sun and the rain. The more time the sun is exposed to the sunlight the hotter it will become. If the roof is also a darker color, the heat is absorbed and the structure below can become a regular oven.

The conventional roofing options transfer the heat they absorb into the insulation below and filling the attic. The heat is then radiated throughout the home and places strain on the cooling function, increasing the costs of cooling the home.

The difference with the way the “Cool Roof” works is all about stopping the heat from soaking through the roof and into the living quarters below. Which means that the AC unit wont have such a difficult time keeping the temperatures of the home at a comfortable cool.

Energy Efficient Roofing employs two capacities to provide a cooling function. This is reflectance and emittance. Cool Roofs with higher reflectance and emittance ratings can stop the transfer of heat far better than traditional roofing options can.

Reflectance is the capacity the roof has to reflect the heat off the roof rather than soaking it up and allowing it into the home. Look for the ‘Solar Reflectance” tab on the product description to pick an appropriate reflectance factor for your home.

Something to consider about the roofing reflectance is that it will diminish over time, the accumulation of dirt combined with the harsh elements can reduce the effectiveness of the reflective film. This is why reflectance is measured in performance after a certain number of years usually three. With this in mind, you can significantly prolong the life of your roofing reflectance by keeping it cleaned and well maintained.

Thermal Emittance is the capacity of the roof to release heat rather than absorb it. On the product specification sheet you will see an emittance ranking from 1 to 10, with higher ratings absorbing more heat. It is the quality of material used to manufacture the roof that determine the thermal emmittance it will provide.

The Pro’s and Con’s Of Cool Roofing

The Pro’s:

Reduced Cost of Energy Bills

The less heat is passed into the home below the less the AC unit will have to struggle to keep your home nice and cool. According to the Council on Cool Roofing, the appropriate roof can save as much as 15% of the energy used to cool the home.

Improved Comfort

Even if you don’t use an AC unit, having a roof that can reduce the temperature of the home inside can make living in the home considerably more enjoyable. If you live in a two-story home, the chimney effect causes the hot air to rise, if the roof is also allowing heat to enter, the temperatures can be excruciating in the bedrooms upstairs.

Longer lasting Roofs

Excessive temperatures and absorption of heat can do a number of the fabric of the roof itself, over time the heat damage can result in leaks, cracks and other damage. The longer lasting ‘Cool Roof’ option can save you on repair costs as well.

Eligibility for Government Rebates

The utility companies operating in certain US communities will offer rebates for the installation of energy saving roofing. Check with your local energy authority to see if any such promotions exist near you.

Con’s:

Lighter Roofs Look Dirty

There was a reason for darker colored roofing, it doesn’t look so bad when the inevitable dust and leaves begin to build up. The lighter colored energy efficient roofs can begin to look bad quickly, but if you are prompt to wash them, they look great and will last longer too.

Cool Roofing May be a Bad Idea in Cold Climates

When the winter rolls around, if they are especially brutal where you live, the cool roof will offer no heat absorption and this may run up your heating costs considerably.

Roof Options

Not all roofing meets the specifications of “cool roofing”. Energy efficient roofing utilizes highly developed materials to function, and if the quality is not up to standard the results will be flawed as well.

Cool Roofing color and materials options:

There are many options for materials in energy Efficient roofing. Tile, metal and asphalt roofing are all available with the Energy Star stamp of approvement. Although metal can be the most efficient material for energy savings.

When it comes to colors, there are many different options to suit the motif of your home. Even better, you won’t be stuck choosing between white, off white and light grey. You will also find a more extensive list of options —even some darker tones— in the metal material section. The ceramic tiles also come in a nice variety of colors and styles.

Reflectance is the capacity the roof has to reflect the heat off the roof rather than soaking it up and allowing it into the home. Stopping the sun before it gets into your roof.

Emittance is the capacity of the roof to release heat rather than absorb it. Depending on your climate, you want to either keep heat in or let it out.