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Our Company

ClearStak, LLC is a privately held environmental testing lab located in Putnam, Connecticut. ClearStak received EPA Accreditation of the lab in Fall of 2016. The lab is focused on partial thermal storage testing for hydronic heaters using biomass products for fuel. Combining both dilution tunnel testing and hand held particulate testing equipment, ClearStak provides a full picture of emissions for biomass appliance manufacturers.


ClearStak aims to be the leading testing facility in the biomass industry by not only offering quality results, but also transparent testing services through the use of several customer-friendly features.

Meet Our Team 

Kelli O'Brien 

Laboratory Manager 

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