Hydrotherm Boilers is a leading manufacturer of high efficiency cast-iron boilers in both the residential and commercial markets with units to fit any application from 70,000 to 3,000,000 Btuh in single boiler applications. Hydrotherm was the originator of the modular boiler concept where multiple single input boiler units were linked together providing maximum efficiency and application flexibility. As a continuation of Hydrotherm's commitment to innovative and state-of-the-art products the KN-Series boiler, the industry's first condensing cast-iron boiler, was introduced over 7 years ago. Hydrotherm is a division of Mestek, Inc., a group of over 36 specialty manufacturers providing diverse residential and commercial HVAC and metal forming products is headquartered in Westfield, Massachusetts with manufacturing facilities across the United States, Canada and China. Family owned since the mid 1940’s by the Reed family Mestek continues to provide industry leading technologies to all HVAC market categories.

Hydrotherm's KN-series condensing cast-iron boiler is the industry's first and only boiler of its kind. Its patented design represents its revolutionary engineering by pairing the ultra-high efficiency performance of condensing boilers with the longevity and durability of cast-iron. All KN-Series boilers are proudly manufactured from start to finish in Boyertown, Pennsylvania by workers with generations of foundry and manufacturing expertise. Controlled through HeatNet, Hydrotherm's proprietary integrated boiler management system capable of communicating and controlling up to 16 inter-connected units, KN-Series boilers feature a self-adaptive design that is tolerant of the continuously changing conditions in today's real world boiler applications.

All KN-Series boilers are designed to burn "clean and green" with its Tru-Flow fuel management technology. KN's fully modulating burner systems provide operating efficiencies of up to 99% for optimal efficiency at all heating loads. All KN-Series boilers are fully factory assembled for ease of installation. Units feature small footprints and are engineered for peak system performance and serviceability right out of the box.

Hydrotherm also offers complete product and boiler efficiency application training through their educational resource center, the Mestek Institute. Class curriculum and dates can be found by visiting