A Closer Look into Cool Roofs

Cool Roofs and Cost Savings for Commercial Building Owners

As a commercial building owner with a flat roof, you know first-hand that your roof is a cost-intensive investment. Once the initial costs of installation have been paid, you have maintenance and cleaning fees, snow removal, and possibly repair costs if those are not covered under your warranty.  An additional factor you may not have considered is the impact of your roof on your yearly energy costs. With the continual rise in energy costs over the past 2 decades, business owners and roofing system manufacturers are increasing their focus on keeping heating and cooling costs down.

One of the most effective ways of keeping your commercial building energy costs down is to choose a “cool roof”. So, what exactly is a cool roof? The Cool Roof Ratings Council (CCRC) is an independent organization that verifies and labels roofing products and certifies them if they meet certain criteria. The simplest and most effective criterion to measure a highest-performance cool roof is the Solar Reflective Index (SRI).

The SRI is expressed as a value from 0 to 100, with a higher number meaning a cooler roof.  The SRI is measured twice – once when the roof is brand new, and again at the 3-year mark after the flat roofing membrane has aged. The SRI measurements are done in the laboratory for each specific manufacturer and type of roofing membrane. These are listed on the Cool Roofs Directory on Coolroofs.org. As a building owner trying to determine the energy performance of their commercial roof, all you need to do is look at the SRI value for the roofing system that you currently have or are considering for your new commercial roof, without having to decipher and interpret a lot of technical roofing and physics terminology.

So how exactly does a Cool Roof for your commercial building save you money throughout the year?

Cool roofs can save money in several ways in addition to energy savings, such as rebates and incentives, HVAC equipment downsizing, and extended roof lifetime.

While cool roofs may save more units of energy in the hottest climate zones, climate zones are not necessarily the best indicator of the relative value of cool roofs. For example, the savings might be more valuable in New York City than in Dallas because electricity is three times more expensive in New York.

Roofs wear out and fail for many reasons, and some are linked to temperature. For example, higher temperatures can speed up material degradation. Cool roofs maintain a lower average temperature, so, in principle, this could slow heat-related degradation.

Some utilities and agencies offer rebates and incentives for cool roofs. To find out if there are any programs in your location, visit the CRRC website or DSIRE website and check with Complete Commercial Roofing.

The Roof Savings Calculator, developed by the US Department of Energy, is a simple and free online tool that allows users to estimate cooling and heating savings for flat roofs with non-black surfaces. To use this tool, you will need to answer a few basic questions about your building. The results will show you how much energy savings you can expect to achieve by choosing a high-performance cool roof.

Call Complete Commercial Roofing!

Choosing a roofing system and a roofing contractor are both very big decisions to make. Complete Commercial Roofing has been serving all of Indiana for more than 20 years. Allow us to answer your questions and assist you throughout this process. Reach out to us today at 877-227-5552.

The Solar Reflective Index (SRI) & Your Commercial Flat Roof

Do you know why it’s important to know the solar reflective index of your commercial flat roof?

When your commercial roof has reached the end of its life cycle or has been damaged beyond repair, it’s time to decide what type of new roofing system is best suited to your needs. In the past 20 years, with rising energy costs, roofing manufacturers, government agencies, and consumers have started to focus on keeping energy costs down. One of the most effective ways of doing this is to choose a “Cool Roof”, and the easiest way to ensure that you are choosing the highest-performance cool roof is to look at the Solar Reflective Index (SRI).

The SRI is a simple yet comprehensive way of qualifying a cool roof with a single, easy-to-read number value. The SRI is expressed in digits from 0 to 100, with a higher number meaning a cooler roof.  The SRI is measured twice – once when the roof is brand new, and again after 3 years.  It was developed by the Lawrence Berkeley National Laboratory and is the result of many measurements input into a rather complicated mathematical formula.  As a building owner on the market for a new commercial roof, all you need to do is look at the SRI value for the roofing system that you are considering, without having to decipher and interpret a lot of technical roofing and physics terminology.

The Cool Roof Rating Council (CCRC), an independent organization that verifies and labels cool roofing products, has endorsed the Solar Reflective Index as the best method of certifying a cool roof. They do continue to use the older rating method as well, which involves taking two measurements — how well the roof surface can reflect light energy (solar reflectance) and how quickly the surface releases absorbed heat (thermal emissivity).  This 2-value measuring system was fairly effective and gives a general idea of how energy-efficient a “cool roof” will be, but it has several limitations. For example, a roofing system might have high solar reflectance and poorly release absorbed heat. Or it might not reflect the sun very well, but it is great at releasing absorbed heat.  Which is better? What about winds over the roof surface, or insulation in contact with the roofing materials? The old method leaves us scratching our heads.

If you are considering a new Cool Roof for your building and would like to know more about the Solar Reflective Index, including a rating of specific roofing systems by manufacturer, you can visit the Cool Roofs Directory at Coolroofs.org.

The table below gives a general overview of the SRI values of common types of commercial roofing systems.

 

Roofing System SRI 3-yr SRI
Single Ply PVC, white 108 90
TPO, white 98 83
EPDM, standard black -3 -3
Metal, white 77 77
Asphaltic Membrane, white 32 27

 

Reach out to Complete Commercial Roofing, we’d be happy to answer any additional questions you have about this topic. Call 765-457-4848 today!

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