HOW MUCH ENERGY DOES A REFLECTIVE ROOF SAVE?
We have written pretty extensively on our blog about the benefits of a reflective roof and how it saves you energy. However, in those posts, we’ve never gotten too specific about how much energy a reflective roof can save you. Is there an exact number? Not really, it can vary from one building to another depending on a number of factors. However, there are ranges and estimates that can give you a good idea of how much you might save. Let’s see what a reflective roof can do for you.
How Does a Reflective Roof Help?
For anyone who may not know, a reflective roof coating saves energy in your building by reflective UV rays back into the atmosphere. Most roofing systems absorb UV rays, and that heat is transferred into the building. This means in the summer, you have to run your AC more to heat the building just because the sun is shining. A reflective roof doesn’t allow those UV rays into the building, and therefore reduces the amount of heat coming in.
Causes for Variations in Savings Amount
You can install a reflective roof on your building, and it will reflect the sunlight and save you energy in that way. However, you might still be wasting energy in other areas that a reflective roof can’t help. For instance, if your energy bill is high because you have poor insulation in your roof and walls, a reflective coating can’t fix that. The coating will save some energy due to its reflectivity, but it can’t fix problems it’s not designed to. If you have bad drafts around your doors, or high-energy consuming light bulbs and appliances, you will still receive benefits from the reflective coating, but they won’t make a large dent if you’re wasting lots of energy in other places.
How Much is Reflected?
So what percentage of UV rays are reflected when you have a reflective roof on your building? Based on several EPA studies, roughly 88% of UV rays are reflected off a white silicone roof. Compare that with a 17% average for non-reflective roofs, and that’s a huge improvement. That can be the difference of about 60 degrees in roof temperature. Depending on your insulation in your building, that can be between 20 and 30 degree difference below the roof. What a difference!
Expected Energy Savings
Reflectivity, however, is not the goal of a reflective roof. Reflectivity for reflectivity’s sake is pointless. What matters is energy savings and dollar savings. So, how much of those can you expect from a reflective roof? According to the EPA, you can expect net annual savings of just under 50 cents per square foot of roof. For a system that generally costs between $2-$3 per square foot, you can see that it won’t take long to recoup your costs through energy savings.
A study performed by the California Energy Commission also found that a reflective roof can reduce a building’s energy use by as much as 20%, which results in major savings as well.
What About the Winter Penalty?
As we always cover when we address reflective roofs, there is a “winter penalty” associated with reflective roofs. In the winter time, you actually want the sun to heat up your building so that you can run your heating unit less often and less intensely. A reflective roof doesn’t allow the sun to heat your building. However, due to the angle of the earth, the sun is less intense in the winter. So you miss out on less heat in the winter while avoiding more heat in the summer. This difference means the winter penalty isn’t nearly as significant as the summer savings.
A reflective roof can save you serious money. Enough to pay for the cost of the roof coating in only a few years. There has been very concrete research into the effectiveness of roof coatings, and we’re proud to offer such an environmentally friendly product. Contact us today if you’d like to learn more.