Roof Coatings: Increase Energy Efficiency By Increasing Your Roof's Reflectivity And Emissivity

You don't have to install a whole new roof to realize many of the benefits of a more energy efficient roof. For many people, applying a roof coating can do much a home's reflectivity and emissivity. These two things can help you achieve some of that often talked about efficiency without resorting to a new roof or a reroof job.

Reflectivity and Emissivity

These two words can seem a little heavy, but they're easy to understand. Reflectivity is the roof's ability to reflect solar rays, and emissivity is the roof's ability to release any heat that it absorbs. These two things in conjunction can give you an incredible boost in energy efficiency. Here's how it works.

The lighter the color, the more light it reflects. If your roof is bouncing energy from the sun rather than absorbing it, then there's less heat for the roof to absorb. But it's your roof's emissivity that dictates what happens to the bit of heat your roof does absorb. When your roof absorbs a lot of heat, it heats up the rest of your home by several degrees. That's because low emissivity means the roof refuses to let the heat go. The longer it holds onto that heat, the harder your HVAC system has to work to compensate for the additional heat.

How a Roof Coating Can Help

A roof coating can add both reflectivity and emissivity to your existing roof. But here's where you have to show a little care. Not all coatings are the same. Pay attention to the rated levels, or the solar reflectance value.

Reflectivity often shows up as a percentage; for example, the product may reflect 70% of the sun's rays. You may also see it in decimal form (.70). The higher the percentage, the better the coating is at reflecting. However, these values can drop over time if you don't use a high quality coating.

The emissivity level also has a decimal number, or thermal emissivity scale value. The thermal emissivity scale ranges from 0 to 1. A rating of 0 represents no emissivity, or ridiculously low emissivity, whereas 1 represents 100% emissivity, meaning that it will re-radiate everything it absorbs. The two values usually complement each other. If the coating has a reflectivity of .70 (70%) then the emissivity will be 0.30 (30%). The two will equal 1 (100%).

Find a Roof Coating Specialist

All of this means that you need to find a roof coating with the proper balance for your particular climate. That's why it's important that you speak to a roof coating specialist. You should definitely speak to one that knows your geographic area. A roof coating can help you save on energy costs, but you need to know which roof coating will work best for your home. A qualified professional like Stetson Painting can also apply the roof coating for you.