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Radiant Barrier Paint VS Xtreme

SUMMARY: The best  co-called "radiant barrier paint" reflects 85% of the radiant heat.  Our Xtreme radiant barrier BLOCKS 95% making it better and less costly that paint.

With the rise in popularity of radiant barrier insulation, there has been an influx of products marketed under the term radiant barrier paint that are designed to be sprayed on the underside of the roof decking in the attic.  These so called radiant barrier spray products are merely paint solutions with added metallic flakes designed to reflect heat and are NOT true radiant barriers per the radiant barrier definition set forth by the American Society of Testing and Materials International (ASTM) which governs the testing standards of building materials.  

ASTM Radiant Barrier Definition: a product must have a low emittance of 10% or less and high reflectance of 90% or more to be classified as a "radiant barrier."

Our RadiantGUARD® Xtreme radiant barrier insulation products have an emittance of 5% and a reflectance of 95%;  far exceeding the ASTM's radiant barrier minimum classification requirements.

More accurately, such radiant barrier spray products are classified as Interior Radiant Control Coatings IF they are tested by ASTM C1321 "Standard Practice for Installation and Use of Interior Radiation Control Coating Systems in Building Systems" and pass the minimum reflectance of 75%.

Radiant Barrier Spray Comparisons

In 2006, David W. Yarbrough, Phd, PE conducted testing of the reflectivity properties of leading reflective paints.  He found that the reflectivity of these radiant barrier paints varies widely.  In fact, ONLY SIX of the products tested actually passed the ASTM minimum requirements to even be classified as an IRCC intended to reduce heat trasfer, yet alone the requirements or a radiant barrier.

Details of the findings can be found in Dr. Yarbrough's heat reflective paint study.

Product Manufacturer/Distributor Reflectivity Radiant Barrier Paint? IRCC?
Radiannce E025 Chemrex 77%


Formula A Barrier Coat #85 Hy-Tech 34% NO
Formula B Barrier Coat #85 30% NO
Barrier Coat #233 11% NO
HeatShield R-20 Kwik Co. 10% NO
Koolcoat Pawnee Specialties 14% NO
Radiosity 3000 Green Building Supply 11% NO
E-Barrier Sherwin Williams 64% NO
Heat Bloc 75 STS Coatings, Inc. 78% NO YES
HeatBlock-Ultra 80.5% NO YES
Lo/Mit-1 Solec-Solar Energy Corp 77% NO YES
Lo/Mit-2 77% NO YES
Lo/Mit-II Max 85.3% NO YES
Insuladd-RBC Tech Traders 41% NO
Insuladd-White 10% NO
Insuladd-White on RBC 14% NO
Therma-Guard White United Community Services of America 14% NO
Therma-Guard Silver 43% NO
Therma-Guard White on Silver 15% NO


As can be seen above, the best spray on radiant barrier products are HeatBLOCK Ultra and LoMit-II Max. When installed correctly by a commercial contractor, these radiant barrier sprays can block between 80-85% of the radiant heat.  But installing a radiant barrier spray solution is not an easy task for a do-it-yourself-er.  In fact, getting expected results from a reflective paint requires the following:

  1. The paint is NOT diluted.  In order to cut costs, some commercial installers will actually mix a thinner paint solution with water in order to get more coverage.  Doing so greatly reduces the product's ability to block the radiant heat.
  2. An even and adequate coverage is sprayed to the roof decking (and rafters).  Under applying the radiant barrier spray is another way contractors attempt to cut costs and that means the results are less than ideal.  In fact, the real results of most radiant barrier paint applications is typically around 20-40% reflectivity.

Along with the fact that it's important to apply radiant barrier paints correctly, the installation of spray on radiant barriers are also best left to the commercial contractor for the following reasons:

  • installation requires wearing proper clothing and a face mask due to the paint fumes.
  • a special commercial-grade spray compression is required to apply appropriate pressure to ensure correct coverage (the use of a paint roller is not acceptable due to roofing nails and complexity of roofing structures).

Radiant Barrier Spray vs. Foil

Our RadiantGUARD® Xtreme radiant barrier reflects 95% of the radiant heat making them FAR SUPERIOR to any heat reflective paint and are much easier to install than a radiant barrier spray making the installation an easy DIY job.

Additionally, RadiantGUARD radiant barriers provide a quicker ROI (return-on-investment) because they block much more heat than the radiant barrier spray products and cost less to install because they don't require any special clothing or equipment and can be installed by the homeowner.

View and purchase our radiant barrier insulation.