Membranes Are Not The Only Cool Roofs Available

When we think of “cool roofs” we often think of the TPO membrane roof because of it’s bright white color. However, the typical membrane roof is not the only game in town. Did you know that there are many colors of metal roofing that also qualify as “cool” roofing?

Florida Power and Light conducted a study on roofs and electric bills a couple of years ago. While the study confirmed long held beliefs that the whiter, and therefore, more reflective the roof, the lower the electric bill. The surprising fact that came out of the study was that, “white, galvanized metal roofing material saves the most energy as a result of its high reflectance and superior ability to cool quickly at night.”

But, there is even more good news, white is no longer the only approved “cool” color when it comes to metal roofing. In fact there are dozens of approved “cool” colors in metal roofing, so you do not have to give up the look you want to get the energy savings you need.

Want to find out more about cool metal roofing, simply call one of our Customer Service Representatives today at 877-726-2661.

Cooling It Down: Lower Energy Bills with Cool Roofs

Cool roofs are a simple and effective approach to lowering the cooling energy loads of buildings and for increasing occupant comfort. By reflecting solar radiation, cool roofs reduce the amount of sunlight that is absorbed as heat in a building. As a result, the need to control indoor air temperatures with air conditioning systems (A/C) decreases, which in turn lowers energy bills.

In addition to energy cost savings, cool roofs contribute to grid stability by lowering the need for A/C use during the hottest times of the year. Cool roofs also reduce outside ambient air temperatures, which helps mitigate the urban heat island effect, a phenomenon where cities can become several degrees hotter than surrounding less developed areas.

Cool Roofs: The Basics

A "cool roof" is any roof surface comprised of highly reflective materials that keep the sun from heating up a building. At RAMCON, we install cool roofing options in almost any roofing material, and innovations in product formulation have enabled us to install systems in a variety of colors as well.

The performance of these materials is rated based on two radiative properties: solar reflectance (SR) and thermal emittance. The reflectivity of a roof’s surface is important because on hot, sunny days, standard dark roofs can be up to 90°F hotter than the ambient air temperature.

 

Cool Roofing Considerations

As with any building envelope strategy, there are several factors to take into account when considering the installation of a cool roof. While cool roofs are ideal for many buildings, their success depends on several factors, including the attributes of a building and the scope of the project. In general, cool roofs have the most benefits for facilities in very hot climates like ours that rely significantly on the use of A/C to control indoor ambient air temperatures and on facilities with little insulation, such as some warehouses.

• Project scope. Cool roofing options vary greatly based on whether the project is a new construction, complete reroof, or renovation of an existing roof. Examples of renovation options include coating an existing flat roof with a cool or light colored coating or installing a single-ply roofing system over an older metal roof.

 

• Facility specifics. Roof slope, location, and size greatly impact the reflective properties of a cool roof. Because low slope and flat roofs cannot be seen from street level, highly reflective, smooth, and bright white materials can be used without visually impacting the surroundings.

 

In addition, other building factors are important to consider, such as the number of floors and the amount and type of insulation. Cool roofs have the most impact on the upper floors of a building, with cooling energy savings between 15% and 25% for the top floor and savings of 5% to 10% for the next floor down. Unfortunately, there is usually less of an impact on overall cooling loads for high-rise buildings.

 

• Other roofing material factors. Our team at RAMCON considers many factors when selecting the right system for your facilities, such as compatibility with existing roof systems, ease of maintenance, and warranty requirements.

 

Cool roofs are an optimal approach to reducing the cooling-energy load of buildings, particularly during the hot summer months when A/C demand is high. The benefits of reduced energy usage from cool roofing materials includes lower energy bills, energy grid stability, and cooler environment overall.

Is This The Future Of Cool Roofing?

Scientists at the Massachusetts Institute of Technology (MIT) have recently invented a new smart roofing tile called “Thermeleon” (rhymes with “chameleon”), which is thermochromic – in other words, when it is exposed to heat it changes color from black to white, and vice-versa.

Thermeleon works by sandwiching common polymers between several flexible plastic layers. When it is cold outside, the polymer solution stays dissolved and the black rear-face shows through to absorb the natural heat. When it heats up outside, the polymer solution condenses to form light-scattering droplets (in other words, it turns white), to reflect the heat.

We now know that a white roof reflects up to 80% of the sunlight, keeping the interior of the building beneath the roof much cooler. This can result in a 20% reduction in summer air conditioning costs. But during the winter months when you would rather your roof capture as much heat as possible from the sun, the black coloring has the reverse effect - these tiles scatter only 30% of incoming solar radiation, thereby helping to keep the building beneath the roof warmer (reducing heating costs).

The team at MIT is now working on micro-encapsulating the chemicals to create a commercially-viable, paintable or spray-on roof coating. If they can figure out how to produce this roof coating at a favorable price and proves to be durable enough for the extreme summer months in regions like we have in Florida, this could very well be a sneak peek at the future of cool roofing.

White, Green, and Cool: Maximizing The Value Of Solar-Reflective Roof Membranes

Roofs are an important element in green, sustainable, architectural solutions. One of the more interesting concepts in energy efficiency is the “cool roof,” also sometimes known as a “white” or even “green” roof. The terms are not really interchangeable -- the cool roof concept is specifically defined by the Cool Roof Rating Council (CRRC) as a roof membrane (single-ply, built-up, or modified bitumen), field-applied coating or other type of roof cover (such as sheet-metal), with both a specified initial solar reflectivity and an “aged” reflectivity value. The basic concept -- reflecting the sun’s heat, absorbing and then emitting solar radiation -- is well established.

Cool roofs are definitely green (to the extent that they are sustainable and minimize adverse environmental impact) and may contribute to interior comfort while reducing energy expenditures, but they are not the garden-surface variety of the term “green roof.” Green roofs are also commonly designed with high insulation R-values.

The cool roof idea has been around for several decades, but it has gained importance with increasing environmental concerns. Building codes feature stricter standards regarding R-values and roof materials (e.g., thermal resistance value must be 20 or greater), while environmental issues add a social awareness element -- cool roofs can enhance your reputation. Materials have changed, too; a wide variety of roof membrane and coating materials are available to designers, including light (but not necessarily pure white) colors.

Caveats for Cool
Cool roofs, if properly maintained, can also reduce energy costs, thus beneficially impacting an owner’s bottom line. There are some caveats regarding cool roofs, however. 

Roof surfaces should be positively sloped to minimize the accumulation of dirt in low spots and to likewise aid in “self-washing” during normal rain.  Cool roofs are particularly appropriate for warm, sunbelt-style climates like ours with greater demands for cooling rather than heating.

Targeted Maintenance
Even when a cool roof is initially effective, targeted maintenance, which is often overlooked, is still necessary for the roof to remain clean and reflective so that it can stay cool and efficient throughout its lifecycle. Dirt, soot, sediment and similar substances will still settle on a cool roof  making the roof darker and less efficient over time. We must invest some time, effort and money in monitoring the roof’s condition and performing cleaning or repairs as necessary. Otherwise, energy-efficiency declines and cool roof benefits are largely lost. 

Lower Energy Bills with Cool Roofs

Managers specifying a cool roof only a few years ago found a limited number of product options. Now, based on the growing demand in part by institutional and commercial facilities, managers can choose from among hundreds of cool products.

By reducing the amount of heat transferred to a building’s interior, cool roofs provide a number of additional benefits. These include lower energy bills and longer performance lives for roof systems, as well as cooling equipment.

The environment also benefits from cool roofs. By lowering facilities’ energy use, cool roofs cut down on air pollution — including carbon emissions, which contribute to global warming.

Managers also need to pay attention to the return on investment — an especially important consideration in tough economic times. While some cool-roofing options cost more than standard, non-cool options, a cool roof generally will pay for itself in a relatively short time through savings in energy costs. But managers should note that exact savings depend on a number of factors that include climate zone, product type, building insulation and the type of HVAC equipment used to cool the building.

Understanding the concept behind a cool roof does not fully describe the amount of actual energy savings managers can expect. Savings obviously can vary widely, but the difference in temperature between a cool roof and a regular roof can be large.

Climate, roof performance, insulation and other aspects of the building can cause variations in the exact amount of savings, but cool roofs can yield up to 50 percent savings on cooling loads.

Average savings in the range of 10-30 percent of the cooling energy required is a reasonable expectation for a typical application of cool roofing under normal conditions. This range might equate to a drop in the total electric bill of 3-10 percent. These ranges generally apply to low-rise buildings in regions with significant cooling loads.

Cool Roofs Reject Heat, Lower Cooling Loads

The availability of viable and energy-efficient cool roofing products has expanded greatly in recent years. Building owners and managers, specifiers, and architects increasingly use these products because of their capacity for energy savings.

Managers in institutional and commercial facilities also can achieve several other benefits, such as: lower interior temperatures, greater occupant comfort, and smaller cooling loads on HVAC systems. A growing number of building codes also mandate the use of cool roofs, and more voluntary programs include them as a key element of sustainable design.

By understanding some of the science behind cool roofs and the questions to ask in specifying these systems, managers can more effectively match product options to the organizations’ needs.

How Is It Cool?
Specifying a cool roof for an institutional or commercial facility can be a smart decision, but not everyone is clear on what exactly cool entails. Cool roofs have been around for quite some time and are increasingly popular options in many areas of the United States. Still, managers often do not understand the performance details of cool roofs.

A cool roof is highly reflective and can easily emit the small amounts of heat it absorbs, allowing the surface of the roof to remain cooler, and transferring less heat into the building.

Two radiative properties define a cool roof. Solar reflectance describes the fraction of solar energy the roof reflects. Thermal emittance describes the relative ability of the roof’s surface to radiate absorbed heat. Both of these properties are measured from 0 to 1, and the higher the number, the cooler the roof.

Here is where part of managers’ confusion comes in. Many elements of a roof’s structure, such as insulation, can affect a building’s interior temperature and its performance. These elements are obviously important, but “cool roof” refers specifically to the roof’s radiative surface properties.

It stands to reason that light-colored surfaces have high reflectance, and many early rebate programs for cool roofs used this characteristic as the only requirement. Uncoated shiny metal surfaces reflect the sun’s energy efficiently, but they have very low emittance and, as a result, become very hot during the day. A roof that demonstrates both high solar reflectance and high thermal emittance is essential for managers seeking to improve a facility’s energy performance.

Calculate Your Savings!!!

The ‘GreenSave’ Roof Calculator
This innovative little calculator lets you compare roofing alternatives over a specific time period to determine which system has the lowest life-cycle cost. It is excellent for determining whether higher initial costs are justified by reducing such future costs as operating, maintenance, repair or replacement costs or producing additional benefits, such as energy savings. It’s simple to use by going to http://bit.ly/eHXxoG

Department of Energy ‘Cool Roof’ Calculator
This calculator is designed for facilities to estimate energy and peak demand savings for low-sloped (flat) roofing systems. Remember, what you get out of this calculator is only as good as what you put in. Check it out here http://bit.ly/hQA1jZ

White, Green and Cool - Maximizing the Value of Solar-Reflective Roof Membranes

Roof systems are an important element in green, sustainable architectural solutions. One of the more-interesting concepts in energy efficiency is the “cool roof,” also sometimes known as a “white” or even “green” roof. The terms are not really interchangeable -- the cool roof concept is specifically defined by the Cool Roof Rating Council (CRRC) as a roof membrane (single-ply, built-up, or modified bituminous), field-applied coating or other type roof cover, such as sheet-metal, with both a specified initial solar reflectivity and an “aged” reflectivity value. But the basic concept -- reflecting the sun’s heat, absorbing and then emitting solar radiation -- is well established.

Cool roofs are definitely green (to the extent that they are sustainable and minimize adverse environmental impact) and may contribute to interior comfort while reducing energy expenditures, but they are not the vegetated or garden-surface variety of the term “green roof.” Green roofs are also commonly designed with high insulation R-values.

The cool roof idea has been around for several decades, but it has gained importance with increasing environmental concerns. Building codes feature stricter standards regarding R-values and roof materials (e.g., thermal resistance value must be 20 or greater), while environmental issues add a social awareness element -- cool roofs can enhance your reputation.

Caveats for Cool
Cool roofs, if properly maintained, can also reduce energy costs, thus beneficially impacting an owner’s bottom line. There are some caveats regarding cool roofs, however. 

Roof surfaces should be positively sloped to minimize the accumulation of dirt in low spots and to likewise aid in “self-washing” during normal rain.  Cool roofs are particularly appropriate for warm, sunbelt-style climates like ours with greater demands for cooling rather than heating, especially for buildings with minimal thermal roof insulation. 

Targeted Maintenance
Even where a cool roof is initially effective, targeted maintenance, which is often overlooked, is still necessary for the roof to remain clean and reflective so that it can stay cool and efficient throughout its life cycle. Dirt, soot, sediment and similar substances will still settle on a cool roof to some extent making the roof darker and less efficient over time. We must invest some time, effort and money in monitoring the roof’s condition and performing cleaning or repairs as necessary. Otherwise, energy-efficiency declines and cool roof benefits are largely lost. 

Management Specialists
The best way to ensure proper maintenance of cool roof systems is our MyRAMCON Star Program (Preventative Maintenance Programs). Our programs include predictive modeling of where problems may occur, a database of various roof systems for comparison purposes, and “what-if” simulations to forecast the impact of various interventions (modify, repair, replace). We can also advise on upgrades from conventional to cool roofs, perform feasibility studies and prepare you for the challenges of altering the existing design.

Are cool roofs a cure-all for environmental and energy-efficiency challenges? No. But combined with an appropriate sustainable roof system design and an intelligent use of a MyRAMCON Star Plan through its life cycle, a cool roof can be greener and more cost-effective than other conventional alternative systems.

Picking A Cool Roof: SRI Index Is Key

Most roofing industry experts agree that a cool roof is one that exhibits a combination of high reflectivity and high emissivity. But the questions have always been how high is high and what combination of the two yields the most benefit?

One way to make a decision is to use the Solar Roof Index (SRI) to evaluate a cool roof. The U.S. Green Building Council's LEED 2.2 uses SRI as a way to evaluate a cool roof. LEED version 2.2 is the first national specification to use a relatively new measure of reporting a cool roof’s properties. LEED 2.2 sustainable sites credit 7.2 states that to receive one point, building owners should use a roof with a Solar Reflective Index (SRI) of 78 over at least 75 percent of the roof’s surface for roofs with slopes less than 2:12.

SRI is a unit developed by scientists at Lawrence Berkeley National Laboratory. SRI incorporates reflectivity and emissivity properties into one, easy-to-read, standardized measure so that roof buyers won’t have to scratch their heads and try to figure out if a high reflectivity and low emissivity is better or worse than a medium reflectivity and high emissivity.

SRI is calculated with a complex formula spelled out in ASTM E 1980 and is a scale of 1 to 100 that is a measure of a roof’s combined thermal properties. It is defined so that a standard black (reflectance 0.05, emittance 0.90) is 0 and a standard white (reflectance 0.80, emittance 0.90) is 100. But some hot roofs can have negative values, and some white thermoplastics and white roof coatings have scored as high as 104 to 110. SRI as a method for reporting cool roof data will probably take a little while to catch on. Most manufacturers still report separate emissivity and reflectivity data in their literature, but the Cool Roof Rating Council, an organization that verifies and labels cool roofing products has begun using the measure, while retaining reflectivity and emissivity measurements.

Different roofing technologies have different SRI values. Asphalt coatings for example have aluminum pigments added to asphalt cutbacks and emulsions to give coatings solar reflectance index (SRI) values of 21-30 on a scale of 0-100.

Acrylic elastometers on the other hand, a new-generation coatings, have a highly reflective surface, often with an SRI greater than 100. Most highly reflective acrylic elastomers are white, and workers can install them over existing bituminous or non-bituminous roofing. Acrylic elastomers typically are specified at 12 mils for five-year warranties and at 20 mils for 10-year warranties. Some manufacturers specify up to 40 mil applications.

Explained: Cool Roofing System Rebates

Getting Started
As hard as you might try, it’s just not possible to ignore a roof. In the long run, the roof will always make its presence felt, sometimes in very inconvenient ways- just ask the hospital that had its surgical suite damaged by a leaky roof.

It can be hard to win capital dollars for roofing even in the best of times (that hospital roof failed during a much stronger economy). But roofs in sad shape simply cannot be ignored. If a roof is already a candidate for replacement, re-covering or re-coating, savvy facility executives should go the extra mile and consider cool roofing options.

There are plenty of reasons why. For one thing, some utility providers offer incentives to spur users into purchasing cool roofing systems. A roof that’s both reflective and emissive can provide a range of benefits for the entire organization. A cool roof can significantly cut heating and cooling loads. It can also act as a shot in the arm for public relations efforts.

Finding Help
When it comes to justifying cool roofs in a today's tough economy, rebates from gas and electric utilities are among the surest bets. Generally speaking, the utilities pay back a certain percentage -usually about $.20 on the dollar — after installation and documentation. “Utilities are looking for ways that they can reduce capacity,” says William Kirn, chairman of the technical committee of the Cool Roof Rating Council. “It’s a form of demand-side management, since cool roofing has been shown to push back peak-demand energy use.” A tax deduction of up to $1.80 per square foot is available to owners or designers of new or existing commercial buildings that save at least 50% of the heating and cooling energy of a building that meets ASHRAE Standard 90.1-2001. Deductions up to $.60 per square foot can be taken for measures that meet the criteria for any one of three building system: the building envelope, lighting, or heating and cooling systems. These tax deductions are available for systems “placed in service” from January 1, 2006 through December 31, 2013.

Finally, there may be financial incentives to facilities that are voluntarily built to the rating systems for green or sustainable building systems — such as Green Globes or the U.S. Green Building Council’s Leadership in Energy and Environmental Design (LEED).

On your next project, consider the 'cool roof' option. Discover more by visiting www.ramconroofing.com