Perlite insulation Perlite-based Ceramic Insulation R-Values

  • CERAMIC INSULATION - CONTENTS: Ceramic building insulation products. Advanced Thermal Insulation. Sources of very high-R insulation products, insulating boards, and wall panels for super insulated building construction and other applications
  • Solar Age Magazine Articles on Renewable Energy, Energy Savings, Construction Practices
  • POST a QUESTION or READ FAQs about using super high-R value ceramic insulation in buildings

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Ceramic building insulation for super high R-values:

This article discusses the use in buildings of ceramic insulation, a variation on perlite insulation material produced by superheating.

Accompanying text are reprinted/adapted/excerpted with permission from Solar Age Magazine - editor Steven Bliss.

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Q&A on Super High R-Value Insulation Products

The question-and-answer article below paraphrases, quotes-from, updates, and comments an original article from Solar Age Magazine and written by Steven Bliss.

Information on Ceramic Insulation Products for Buildings


We are about to re insulate our cathedral ceiling and have only the 2 1/2-inch dept of the purlins for insulation space. In September 1980 Popular Mechanics had an article on a ceramic insulation that claimed an R-value equivalent to 70 for 3 inches of thickness. Do you have any evaluation of this product? - Peter Slavish, New Hope PA


The ceramic insulation written up in the Popular Mechanics article is a variation on Perlite Insulation, an insulation that has been around for years. Perlite is made by heating silica ore to 1600 degF, causing it to expand. The ASHRAE Handbook of Fundamentals says expanded perlite with a density of 5 to 8 pounds per cubic foot has an R-value of 2.7 per inch. [See INSULATION R-VALUES & PROPERTIES].

P.D.I. St. Anne, IL, the manufacturer of the ceramic insulation discussed back in 1980 has patented a process for coating the perlite. The firm claims this boosts its equivalent R-value "in the radiant mode" into the R-70 range. A vented attic space and moving air above the insulation layer are needed for it to work. If the ceramic insulation is placed in a sealed space with no air circulation above it, P.D.I. says its R-value drops back to the "conductive" R value of 2.7 per inch.

In 1985 Solar Age contacted Oak Ridge National Lab in Oak Ridge, TN, for an expert opinion about ceramic insulation based on perlite. The lab's David McElroy said that thermal tests on ceramic insulation "indicate the material behaves very much like perlite, and does not have the high thermal resistance the manufacturers claim."

Oak ridge had insulation makes with accurate test facilities test the ceramic insulation. Their results came in at or below the Oak Ridge levels. National Research Council of Canada also confirmed these findings. Asked if the "radiant mode" explanation sounded plausible, McElroy said "No."

For an update on SUPER HI-R INSULATION including ceramic based products that do have very high R-values (and are very costly, hence used in special applications) see SUPER HI-R INSULATION.

Current High-R Building Insulation Products for Super Insulated Buildings

The high-R insulating panel building products currently in most common use
also polyurethane spray foam (URETHANE FOAM Deterioration, Outgassing).

These materials have a typical R-value of about R-5 to R-6 per inch, though when installed with a radiant surface (that might help) and a 3/4" air gap, the R-value is increased substantially - as we detail below. Fiberglass batts, which are still most-widely used in residential construction, are about R-3 per inch.

Here are some currently-available high-R building insulation products as well as some specialty very high-R insulation materials:

This article is reprinted/adapted/excerpted with permission from Solar Age Magazine - editor Steven Bliss.

Here we include solar energy, solar heating, solar hot water, and related building energy efficiency improvement articles reprinted/adapted/excerpted with permission from Solar Age Magazine - editor Steven Bliss.

Original Solar Age Magazine article on ceramic insulation

The link to the original Q&A article in PDF form immediately below is preceded by an expanded/updated online version of this article found above.


Continue reading at SUPER HI-R INSULATION or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.


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