Designing a standing seam metal roof can be complex. As an architect, you need to understand best practices for keeping a metal roof stable and effective while also keeping its overall appearance in mind. Commercial projects can add even more complexity, as these can often be sprawling, multi-faceted structures with many factors to consider.
Metal roofs are a common choice for commercial projects because of their sustainability benefits, including cool metal roofing, which uses unique pigments in the paint system to reflect the sun. Still, architects may have trouble finding the right information on cool metal roofing, or could be wondering whether they should choose a particular color for their design to boost energy efficiency.
So how do you know which color is right for your commercial metal roofing project?
Sheffield Metals International (SMI), a leading supplier of metal coils and sheets, is dedicated to providing accurate, helpful information to our customers. Whether you’re an architect, contractor, or homeowner, we’re here to offer you our expertise and make sure you’re making the right decisions for your project. We have a full architectural team on staff who have decades of combined experience and in-depth knowledge of metal roofing materials.
In this article, we’ll uncover what the best color really is for energy cost savings on commercial metal roofing projects, including other subtopics such as:
- How significant color choice is for energy cost savings
- Factors involved with energy cost savings on metal roofs
By the end of this article, you’ll know which colors work best for energy cost savings and have a better idea of how to best approach this design consideration for your unique project.
Background: What Is Cool Metal Roofing?
For background, cool metal roofing refers to coated metal products that reflect the sun’s energy to dissipate heat. These coatings have solar reflective pigments built into the paint. Some metal roofing colors are more effective at keeping roofs cool than others.
The effectiveness of different colors for energy cost savings is measured using a system called the Solar Reflectance Index (SRI), which takes into account solar reflectance and emissivity:
- Solar reflectance: This refers to the ability of a material to reflect solar energy back into the atmosphere. Measured on a scale of 0 to 1, with true black being 0 and true white being 1.
- Emissivity: How well a surface releases or emits absorbed heat and returns to its normal temperature. Also measured on a scale of 0 to 1, with 1 being the most effective at emissivity.
The Solar Reflective Index (SRI) uses both of these measurements in a formula to obtain an SRI value for a particular color, measured on a scale from 0 to 100 – 100 being the most effective for energy cost savings.
What’s the Best Color for Energy Cost Savings on Commercial Metal Roofing Projects?
The easy answer? White.
If you do any research to find the colors with the best SRI values, you’ll find white shades at the top, because of the natural ability of this color to reflect and emit heat. Just like wearing a white shirt versus a black shirt to the beach, white metal roofs will do a better job of keeping things cool.
So, if you’re looking for a strictly functional color that will give you the best chances at energy cost savings in the future, choose white. Typically, you’ll find a fairly big drop-off in SRI values once you venture out of white color options.
Remember, however, that there’s more to consider than just color choice when it comes to energy cost savings on metal roofs.
How Significant Is Color Choice for Energy Cost Savings on Metal Roofs?
There are many reasons why metal roofs are becoming more and more popular on both residential and commercial buildings, and certainly one of them is their sustainability attributes. Metal is a recyclable material and also lasts much longer than other traditional alternatives like shingles, surviving for sixty years or more without replacement.
Energy cost savings are another added advantage for metal roofs. By choosing a color with a high SRI value such as white, building owners can save money on their monthly bill. Now, how much money this will save is dependent on a variety of factors.
You can estimate the specific cost savings of a facility through provided tools like the Cool Roof Calculator, which was developed by the U.S. Department of Energy’s Oak Ridge National Laboratory. This tool allows you to plug in your unique project’s attributes to get an understanding of your annual savings by using a certain color.
What you’ll likely find by using this tool is that cost savings will be dictated by a lot more than just color choice. The region, the specific design of your roofing project, and the insulation can all have an effect on the savings of a metal roof.
Factors to Consider for Energy Cost Savings on Your Commercial Metal Roof Project Color
Region
The region a project is located in will heavily dictate how much energy you can save on a metal roof. Those who are based in areas that get hours of intense, focused sun, such as the American Southwest or Florida, can expect to gain more from choosing a high SRI color than building owners in the Midwest, where sunshine and extreme heat aren’t as prevalent.
Roof Pitch
The slope of a roof also has a significant impact on the effectiveness of energy cost savings. Roofs that are flatter face greater exposure to the sun for longer periods. Colors with high SRI values will perform well on low-slope roof designs, as they can reflect solar energy and emit heat efficiently.
Gloss
High-gloss metal roof colors tend to have higher SRI values than low-gloss options. Remember, however, that high-gloss colors are also more prone to oil canning, while low-gloss colors are better at knocking down those effects. It’s important to weigh the functionality you’re looking for versus any aesthetic preferences.
Insulation
Great insulation can help a building remain at a constant temperature, regardless of the climate outside. With quality insulation, you may find that the color you choose for your metal roof might make less of a difference, as the insulation is doing its job well and already keeping the outside temperatures out. Building owners with weaker insulation, however, may find more benefit in choosing a color with a high SRI, as it can help reflect and emit heat before it penetrates the roof.
Roof Size
Also, consider the size of your project when determining the energy cost savings on your metal roof. Huge projects with a lot of surface area will likely experience more savings from a color with a high SRI value than smaller projects that don’t have to emit as much heat.
Leadership in Energy and Environmental Design (LEED) Certifications
The Leadership in Energy and Environmental Design, known as LEED, provides a certification to label a building as healthy, highly efficient, and cost-saving. LEED is used widely as a universal building rating system for sustainability, and it uses SRI values as a means to determine whether a specific building is LEED-compliant.
This certification can be a symbol of an organization’s commitment to sustainability. It is something else to consider when choosing a color for your commercial metal roofing project.
Looking for More Information on Metal Roof Colors and Energy Cost Savings?
Choosing the right color for a commercial metal roofing project involves taking into account many different factors. While choosing a color like white can offer you a high SRI value and potential energy cost savings, the exact amount will depend on many other factors.
To help narrow your options and understand all the different factors involved with choosing a color option, it can help to consult with metal roofing experts. A metal roofing supplier like Sheffield Metals, with decades of experience in the industry, can help guide you in the right direction.
Sheffield Metals has a full architectural and technical team on staff that can provide you with information on color choices and technical information about your particular roof. If you’re looking for guidance on designing for your metal roofing project, reach out to our team today.
