Johns Manville Releases the First R-12 Fiberglass Duct Wrap

DENVER--(BUSINESS WIRE)--Johns Manville (JM), a leading global manufacturer of energy-efficient building products and engineered specialty materials and a Berkshire Hathaway company, announced today the release of the first-ever fiberglass duct wrap with an installed thermal resistivity rating of R-12: Microlite® FSK. This Formaldehyde-free™ duct wrap is designed specifically to meet new code requirements set forth by the IECC in 2015 that mandate the use of R-12 insulation on ducts in unconditioned spaces in climate zones 5-8.

The new 4.4 inch wrap is the newest addition to the JM R-12 insulation portfolio.

“We understand that installers and specifiers need multiple insulation solutions for the varied applications they encounter on a jobsite,” said Brennan Hall, JM’s HVAC Product Manager. “This is why we are offering two new R-12 solutions: Microlite, a Formaldehyde-free™ FSK-faced fiberglass duct wrap, and Linacoustic® RC, a fiberglass duct liner with an antimicrobial coating. Now, contractors can achieve R-12 thermal performance in a single layer of insulation, and they have the variety of insulation solutions they need to meet the unique requirements of varied applications. These two new R-12 products offer the same high-quality performance our customers have come to expect from Johns Manville’s duct wrap and duct liner.”

Johns Manville’s R-12 Microlite duct wrap comes with an FSK facing designed to help ensure a closed system that prevents moisture drive and offers condensation control. This design helps prevent damage to the insulation and surrounding areas. Additionally, the material is GREENGUARD® Gold certified.

R-12 Microlite and R-12 Linacoustic RC round out the JM R-12 duct insulation portfolio with two, high-quality insulation materials that are the only duct liner and duct wrap on the market to offer a single-layer R-12 thermal performance.

The full R-12 insulation portfolio from Johns Manville includes:

  • Microlite® FSK fiberglass duct wrap
  • Linacoustic® RC fiberglass duct liner
  • Linacoustic® R-300 fiberglass board
  • 800 Series Spin-Glas® fiberglass board
  • XSPECT® ISOfoam APF Board (polyiso foam)

For more information on R-12 Microlite, visit:

About Johns Manville

Johns Manville, a Berkshire Hathaway company (NYSE: BRK.A, BRK.B), is a leading manufacturer and marketer of premium-quality products for building insulation, mechanical insulation, commercial roofing and roof insulation, as well as fibers and nonwovens for commercial, industrial and residential applications. JM serves markets that include aerospace, automotive and transportation, air handling, appliance, HVAC, pipe and equipment, filtration, waterproofing, building, flooring, interiors and wind energy. In business since 1858, the Denver-based company has annual sales over $3 billion and holds leadership positions in all of the key markets that it serves. Johns Manville employs 7,600 people and operates 43 manufacturing facilities in North America, Europe and China. Additional information can be found at

Johns Manville Brennan Hall, 303-978-2636 Senior Product Manager – HVAC