TherMix Insulation

TherMix Insulation is one of the most widely used insulation components in the industry today, providing superior structural strength and stability to masonry chimneys. This product is UL listed (1777) with the SmartFlex and Ventinox family of liners, DuraPro and many other liner brands. When properly applied, TherMix effectively insulates the liner, maintaining consistent liner temperatures. As a result, it reduces condensation, increases drafting efficiency and aids in a quick ignition, helping to establish draft and greatly reduce spillage.

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Our Price: $59.99 to $500.99
SKU: TherMix Insulation

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More Information
  • UL Listed 1777
  • Great Solution When Space is Tight
  • Ready To Mix
  • Insulates Liner & Maintains Flue Temperature
  • Tier Pricing Available!

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Field tested and approved, TherMix Insulation is the product of choice by Lindemann Professional Technicians!





TherMix Insulation comes in bags (or boxes) as a dry insulation mix. When mixed with water, it should have the consistency of a damp potting soil. Each bag of Thermix Insulation weighs 40 lbs., and yields 3.25 cubic feet - more than competitors! This product contains vermiculite.









A minimum order of 5 bagged Thermix Insulation is required. Thermix Insulation bags are shipped on a pallet via freight line - fees may apply.



Please select Thermix Insulation boxes when ordering less than 5, and there are no additional items in your cart.







Discounts available! See below for available tier pricing on bagged Thermix Insulation.



Tier Pricing:



1-19 Bags

20-39 Bags

40+ Bags

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Benefits of using TherMix Insulation:



  • No Health Risks: Non-fibrous, non-toxic, inert and manufactured under stringent quality controls. Safe to the installer and homeowner, today and in the future.

  • Adds Safety: Chimneys insulated by TherMix reduce creosote build-up, minimizing the chance of a chimney fire.
  • Superior Performance: Aids in optimal heating efficiency. Due to high "R" values, flue surface temperatures are balanced and react quickly to firing cycles of heating units.
  • Durable & Tested: When properly installed, TherMix does not leak, separate or deteriorate. Field tested since 1984.
  • Reinforces: Insulates the liner & flue gas while providing a strong bond for the masonry chimney.

Calculating the amount of TherMix Insulation needed:



(W x D x H) - (L x H) = Total Volume



Divide this number by 1728 to convert from cubic inches back to cubic feet. Divide the final amount by 3.25 to see how many bags of TherMix are needed.