Cooling Paints: A Misnomer?

A DEFINITION OF “COOLING” as it applies to SOLAR, HEAT REFLECTIVE COATINGS. When coatings/paints can cool buildings and when they may not be enough by themselves~

Cooling – An action by something which actively reduces the kinetic or molecular energy (heat) of an object, person or place.  This implies that an action is occurring upon something already hot or overheated, that cools it. The reason why this is important is because there are numerous cooling paint  products appearing on the market which imply they can cool down your house or building by themselves.  They can be effective depending upon the house type, color and its location relative to the sun.   Bottom line is, IR pigmented solar reflective coatings and some cooling paints can get the building to start “cooling” down if:

1.  The house/building gets hot inside from the sun.

2.  The the house or building stays hot after the sun sets.

If your building has standard non-tinted windows, little or no insulation, a dark roof, solar reflective cool coatings on the walls will lessen these temperature dynamics. However, you’ll have to add some additional items in order to get optimized cooling of the building interior.

THESE ADDITIONS SHOULD INCLUDE A STRATEGIC COMBINATION OF THE FOLLOWING:

A cool roof or cool roof coating.

Plus:  Add a large tree(s) for shading the house/ a solar attic fan or whole house fan/radiant barrier coating or radiant barrier foil on the attic ceiling/ wall and roof insulation/ thermal film on the windows/ window shades or shutters/ add plants around the house/ tear out the asphalt yard or patio and plant a lawn/ cover your concrete patio with an artificial green turf.

Cooling is all relative! For one person, a 10 degree drop in inside temperature is substantial. For someone else, they may be looking for more. Others may be looking for less. The contrast can be a big change, but in over hot buildings cooling of both the outside and as a result, the inside has has multiple benefits including quality of life and lowered exterior maintenance costs. 

 Two good examples:

I was present for a situation where an office building got both a cool roof and solar reflective, cooling coatings (Thermo-Seal and Eco-Therm Elastomeric) on its two story walls. A female tenant of one of the upstairs offices sometimes to put on a sweater or a shawl because the building now had such a contrast in temperature during really hot summer days from outside to inside.   Meanwhile, everyone else was raving about the cooling difference in the building and in their suites.

In another case, the western US home of a customer had rooms with daytime spring and summer temps over 85 degrees with the AC turned on high.  Their roof was uninsulated metal and had little attic space.  Adding a cool, white roof coating dropped their interior temperatures 12-15 degrees and made all the difference in quality of life and the exorbitant electric bills they we getting.

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So it is important to remember cooling can be felt and perceived differently. Depending upon location and how much cooling you want, you might need to consider a combined approach of more than one technology.  In extreme, sun exposed, hot environments, this is going to be mandatory. However, getting a true solar reflective coating with real IR reflective pigments on your house or building first can be just the change your outside walls and/or roof require to drop those inside temperatures. 

Any cooling technology combo really will take the interior temperatures down so long as you also keep doors and windows closed during the hottest part of the day and opening them at night!

PLEASE SEE other POSTS here at Cool Reflective Coatings Info to understand some of the differences between solar reflective coatings and cooling paints.

ARTICLE Link: Solar Reflective Coatings for Cool Walls and Cool Roofs

Article from CONCRETE POLISHING MAGAZINE (online subscription). SEE: Free Link below>>

See this for a comprehensive scope of understanding of the use of the infrared pigment technology for cooling the “building  envelope”.   It’s not new, but it is still not common here in the US, unless you consider use of the color white in cool roof coatings and on house exteriors. That’s not new.

The coolest wall coatings are white, but if you want some choice and still have a cool property, you’ll need to go with an IR pigments coating product. Also, all white paints and coatings are not created equal. See:

http://concretepolishingmagazine.com/index.php?option=com_content&view=article&id=93:solar-reflective-coatings-for-cool-walls-and-cool-roofs&catid=9:featured-articles&Itemid=2

White Cool Roof Topcoat vs. Aluminum Roof Coatings?

After what you read below, you will become aware that the need to redo aluminum coatings on flat and low slope roofs every few years represents liability and inefficiency versus premium, white cool roof coatings. The complete answers to the aluminized coatings question versus a higher quality, elastomeric low-slope coatings  like that are ENERGY STAR rated are as follows:

1. Aluminum coatings are nowhere near as efficient in reflecting the sun’s radiation, not initially nor after 3-4 years in temperate environments, which is their useful life before they must be re-coated.

 

2. The range of performance on various aluminum coatings from the major manufacturers on the CRRC makes it clear.  All aluminum coatings start out over 20% less efficient in Solar Reflectance (SR) and Thermal Emissivity (TE) and end up on average almost 50% or more less efficient in just 3 years compared to ECO-THERM Elastomeric color white uncleaned, for instance.  Aluminum coated roofs are much hotter than the majority of cool white top-coated roofs (at proper number of coats) even more so because of their poor Thermal Emissivity properties. This means that the aluminum coatings retain heat in the substrate roof much longer. ECO-THERM and some other white coatings actually increase in thermal emissivity in its first three years after installation due to particle compaction. 

3.  Aluminum coatings do not stand up to being cleaned without losing their particles and baring the asphalt, rubber or tar roof underneath. ECO-THERM for example does not attract dirt and is cleanable. Most cool white coatings, however, when washed will not return to their initial solar reflective efficiency due to dirt which embeds in them.

4.  Aluminum coatings are early 20th century technology and are toxic for the environment. They slough off gradually and send their aluminum particles everywhere (wind, rain, snow melt and sun do that job well).

5. Various Federal and university lab tests have  confirmed that cool elastomeric topcoats protect the roof underneath them because 1) they keep them cooler (less wear from thermal shock), 2) they physically prevent water from penetrating the roof layer.

 

Aluminum suspended in a toxic carrier at a few microns of thickness that washs and blows away are not in the same ballpark. Compared to a high quality elastomeric, white cool coating like ECO-THERM, this is not an apples to apples comparison.

 

6. Perhaps only one aluminum coating meets initial LEED credit requirements, but all aluminum coating types and many cool white coatings fall off precipitously as noted by their performance efficiency ratings (initial and 3 year), so if any builder, property owner or corporation is serious about the cool roof issue and ROI (return on investment) for their “cool” low slope or flat roofs, then there is little to be said for aluminized roof coatings except their initial cheapness and initial cheaper labor to install. 

 

Which “cool roof coating” do you now think is a better use of your money and care for your properties?

Cool Colors in Metal Roof Paints and Coatings

SOLAR REFLECTIVE, COOL COLOR COATED METAL ROOFS USING IR PIGMENT TECHNOLOGY

When it comes to metal roof coatings that were factory baked-on and ultra-durable, the trademarked “Kynar” comes to mind.  This technology was and still is made in the fluoro-polymer, solvent-based material and became a dominant, highly durable coating for factory metal panel suppliers. These coatings were developed starting in the 1970′s with stndard orgainc pigments for their color ranges. An option also became availble in the same base material to have colors made with inorganic, mixed metal, infrared (IR) pigment technology developped in Germany which were substanitally more solar reflective in similar colors. Today a larger range of colors is now available from various makers.

FIELD APPLIED INFRARED COATING TYPES

In terms of field applied, metal roof and metal panel IR coatings, these are now available in water-based, acrylics and thermoplastics with ultra-bonding, cross-linking chemistry and acrylic elastomerics  Bottom line is that the same solar reflective IR pigment technology is used and high levels of reflectivity are available, color-for-color as in the factory applied paints. These field-applied coatings clean up with water, are very low toxic and have a higher overall thickness once they are fully dried. However, in order to bond to failing, older Kynar coated metal roofs, some manufacturers are now making specialized “hot” primers, that meet the VOC requirements and adhere very well to the older coated metal.  The acrylic colored IR coatings can be applied over this bonding primer and stick very well.  It is common with some manufacturers to also to have a clear sealer put on over the finished colored reflective coating in order to protect the color coat further, just like the similar purpose clear sealers commonly used on automotive finishes.  This clear coat or “glaze coat” further adds to the dirt shedding quality of the steep-slope, metal roofs.

When full water-proofing is also required for the metal roof, a class of flexible, waterproofing coatings called “elastomerics” is required to seal the metal roof as a whole system. Seams and perforations must be addressed before the alstomeruc is applied with appropriate sealers and resnforcement. This elastoermic coating category is also made for other roof types which are flat or low-slope as well as exterior walls where high solar reflectivity and waterproofing are required.  Key is that a precious few manufacturers make the IR reflective elastomeric coatings, which can also hold colors that reflect the sun’s heat as do the thermoplastics. When used upon walls, any elastomeric product must be able to pass water vapor out through itself so therefore it must be “breathable”. all of this class are not create equal so make sure it both breathes and reflects.

Solar reflective coatings vs. Insulating paints – What’s the truth?

SOLAR REFLECTIVE DOES NOT MEAN IT INSULATES

In the market today you will find two competing exterior finish coating and finish paint technologies which claim the top results for their ability to reflect the sun’s heat.  These are the solar reflective coatings or IR reflective coatings (IR=infrared) and the so-called insulating paints that are ceramic-filled. By definition, the nature of coatings provides for part of the difference compared to paints, since coatings are thicker and more adhesive. Coatings source from an industrial heritage where performance demands were placed by companies requiring longer life cycles across all types of uses.

The infrared (IR) pigments technology in exterior coatings is a German invention and was first used in the field in the hot Australian outback over thirty years ago. Their overall effectiveness depends upon the darkness of the coating color and how exposed the surfaces are to direct sunlight. The infrared reflective, inorganic pigments actually work optimally in the darker colors when compared on a color-for-color basis to standard, organically pigmented paints, the differential generally running 20 to 50 degrees F. cooler for specialized, mixed-metal oxide pigmented coatings.

On roofs similarly, the greatest efficiency occurs where darker roofs are topcoated over with optimized cool color coatings (solar reflective – IR reflective). Even a color black coating, in examples I have witnessed, can be well over 40 degrees F. cooler when applied to a black composition shingle roof or cap-sheet in the correct IR pigment formula. This is revolutionary and applies to solar reflective coatings with IR reflective pigments only in a range of efficient colors. Of course, the color white is the most reflective of all colors. Many companies with no specific infrared pigments, claim the greatest solar reflectance for their white only topcoat. However, not all whites are the same (look for a future post here). Percentage concentration of titanium dioxide, its particle size and purity, and what it kind of quality base it is blended into gives color white its main infrared reflectivity.   However, even grey and beige are now available that are within just 10-12% of the Solar Reflectance efficiency of color white!  This is due to the reflective efficiency of the IR pigment technology. (Learn about ECO-THERM Elastomeric coatings)

COOL COLORS BASED ON INFRARED PIGMENTS CAN DO THE WORK

SEE: Lawrence Berkeley Labs Cool Color Database

Key: The IR reflective pigments with low toxic, mixed metal oxides do the work of reflecting the invisible, sun’s heat wavelengths, the infrared. The tough, water-based acrylic, thermoplastic coatings and acrylic elastomerics coatings made to carry these pigments bond exceptionally. In reflecting away the majority of the solar radiation (the common phrase description for the  infrared heat wavelengths), cooling coatings hold up longer because they are engineered both more cohesively and with greater ability to handle a wider range of thermal shock than paints.  The coatings themselves wear much slower, as well as the wear on building materials underneath them, whether walls or roofs, since they themselves are so much cooler in sunlight than the bare material or when covered by regular paints. Not to confuse, these coatings wear less in part also because they fully block the ultra-violet (UV) wavelength component of sunlight, which carries no heat, but which does actively break down all sun-exposed coatings, paints, films and plastics over time.

COOL ROOF COATINGS  with  REFLECTIVE COLORS  - SECRETARY CHU SPEAKS

Color for color these cool reflective coating products  will be cooler than standard pigmented coatings or paints, even in the color black. In the color white, optimal reflectance will be dependent upon other factors than just the white, titanium dioxide they contain, such as surface smoothness, use of high concentration of top acrylic and no plasticizers to adhere dirt particles onto the coating. U.S Energy Secretary Steven Chu speaking in London on May 26, 2009 made the first press release from the Obama Administration touting the cool roofs information and as well,  the capability of cool reflective colors with “special” pigments.  He is talking about the same subject as we are here.

SEE: Energy Secretary Chu’s Comments

CERAMIC PAINTS CLAIM TO INSULATE AND TO REFLECT HEAT

Ceramic-filled or so-called ceramic insulating paint additive technologies promoted by several companies claim to be an”insulating” paint panacea to make exterior house walls cool have been a nonsensical concept from their outset based upon just one law of physics. Since insulation and it associated mandatory “R- value” measurement in the building industry (R for resistance) have been long established as the  measure of effectiveness for insulation. This is based on thermal mass (thickness & density) and in some varieties, effectiveness in trapping air inside the thick barrier or dense product.  Average paint thickness is a single sheet of paper. Now comes the two sheets of paper thick ceramic-filled paint (up to TEN pieces pieces of paper for some manufacturers), and the claims of insulation value when used to paint any type of exterior wall.  Buildings coated in this way are claimed to be so cool so as to be compared to the space shuttle in how it is protected by ceramic tiles in re-entry to our atmosphere.  This is all smoke and mirrors since the very basis for the R-values claimed cannot possibly be achieved for any substantial length of time by thousandths of an inch of any paint film with insulation elements (ceramic or hollow glass) mixed inside of it.

The paints that are said to insulate do not use the IR pigments at all and would be seen to rely upon the insulative idea for the gains they promise as opposed to true reflection of the infrared, thermal wavelengths from the sun, which heat up surfaces in contact with direct sunlight. SEE:  FTC Cases AGAINST Insulative Paint Manufacturers and,  http://www.ftc.gov/opa/2002/04/kryton.shtm

Why solar reflective coatings now?

A QUESTION OF VALUES AND STEWARDSHIP TO COOL A HOT PLANET

There are always multiple reasons why technological advances that come with positive cultural, global, and societal impact make sense and are taken up successfully by people, but their uptake isn’t always fast. Key is does it really make a difference and does it change quality of life for everyone? Rarely. Does the technology have broad implications that impact both individuals, families, communities, nations, their populations, the natural living world (trees – plants – animals – insects – fish-bacteria – microorganisms) and the global environment positively, without those impacts being negative at some point in their lifespan? If you could decide to make a difference in the climate challenge of our lifetimes with a simple decision to REPAINT your property with  solar reflective coating technology that will benefit everyone, would you do it?

COOL PIGMENTED COATINGS FOR WALLS

Today we have the oportunity to coat most buldings with special infrared pigmented, colored coatings, highly reflective, super-durable paint-like material, that reduces building interior and exterior temperatures 10 to 90 degrees depending upon color comparison, location and original materials being overcoated. They have immediate benefits in the cooling of each building’s “envelope” such that interior quality of life is bettered and air-conditioning use is lowered. Longer term savings mean lessening of all building maintenance costs and wonder of wonders, reduced outside air temperatures from less thermal reradiation of the sun’s heat. Therefore, incremental steps toward reducing global warming are a immediate direct benefit.

Sometimes a vision of newness is visually dramatic and patriotic, even awe inspiring and we all “see” it. A great example was the Space Shuttle. Remember its wonder and validity to further knowledge and provide human access to the edge of space, for scientific, commercial and industrial advantages. Today, we know that it punches holes into the ozone layer, damaging it measurably with each launch and yielding tremendous pollution with detrimental environmental consequences. How about a technology that has way more benefits than demerits for a change?

THE NECESSITY OF COOL COATINGS FOR CONCRETE

An invention intrinsic to the building construction issue is concrete. It is an ancient Roman creation that was a revolution to construction which when reinforced with steel enabled skyscrapers and freeways to come into being. Did you know that concrete stores heat from the sun and it heats up our atmosphere substantially due to its ubiquitous use? Did you know that it deteriorates slowly to probable failure at some point in its life span? Unless it is coated, it will eventually fail and need repair or replacement due to water deterioration to the reinforcing rebar. As it is now, due to the scale and widespread nature of it’s use, concrete is a major contributor to the “Urban Heat Island Effect” since unpainted concrete acts as a thermal heat sink in all sun exposed locations and “re-radiates” the thermally accumulated sun’s radiation into the atmosphere after the sun goes down. The overheated air in cities and suburbs catalyzes more air pollution by chemical reactions which occur as the atmospheric temperatures increase. Massive carbon pollution further occurs from generation of the electricity at fuel-burning utility plants supplying the energy to run air conditioners inside millions of such buildings into the night.

URBAN HEAT ISLANDS ARE MADE OF BOTH CONCRETE AND ASPHALT

Asphalt roads, parking lots, grey concrete slabs, tar and gravel roofs, dark asphalt composition shingle roofs are an even greater cause of the heating up of the atmosphere for the reasons already discussed plus the fact that more heat absorbing surface areas are black asphalt than structural concrete. Translation: Even more heat is stored and reradiated every day when the sun goes down and these surfaces let their heat storage go out into the air.  Cool coating dark roofs and all sun-facing, dark asphalt surfaces, are critical elements to the solar reflective coatings issue.

CARBON FOOTPRINT IS REDUCED WITH COOL PIGMENTED COATINGS

These are major keys to how the carbon footprint is created when the issue of fuel burning to create the electricity to run the air conditioner in buildings is also included in th equation. In the immediate term, infrared, solar reflective coatings must be broadly adopted and supported by legislation and local government.

Could you imagine building a much better rocket ship that is energy efficient and carbon neutral? Could you imagine coating concrete so it is waterproof, breathes, lasts much longer, prevents pollution, saves huge money from lowered electrical use and doesn’t really heat up from the sun? Could you imagine coating the asphalt roads, parking lots and roofs the same way? The former requires a completely new technology, a new rocket ship. The latter requires thinking out-of-the-box, pro-actively choosing a smarter low-impact solution to a ubiquitous problem not practical to be replaced for millions of existing structures. This cool coating technology’s benefits will not let us see global results right away and the majority walking by it on the street level won’t even know the solar reflective coating is there. All solar reflective coated buildings will show their benefits to be measurable right away by lowered electrical use, and as time progresses in locally reduced air temperatures.

Do you know the best answer to the the title question now?

OK, you are now a mini-expert! Most people have no clue about this information and you are called to serve this cause, educating others – for the practical, immediate need to cool coat building walls and roofs with solar reflective coatings. It is a critical pathway change benefitting all of us.
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Sea change comes with solar reflective, cool wall and cool roof paints and coatings, watch!

NECESSITY THAT PAINTING INDUSTRY CHANGES TO COOL COATINGS 

I’ve founded a “green” technology company that makes and distributes solar reflective, “cool wall” and “cool roof” coatings. After over 23 years in the painting industry, I am committed to help create the “sea-change” in the architectural coatings industry to effect mainstream specification and use of these highly heat reflective paints and coatings with infrared (IR) pigments. I will share some of the great info I have learned from here on out on the critical path issues surrounding IR reflective coatings and the reduction of carbon footprint that can occur by using them to reduce the Urban Heat Island Effect (see my next post) . If I am halfway correct, there will be significant and measurable benefits from the broad spread, correct use of these specially pigmented coatings on all exterior building and paved surfaces. I believe that this will be shown to be an understatement. I’ll be happy to be shown just how much so at any time it becomes quantifiable from majority use of these energy efficient, solar reflective paints and coatings. 

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