Hydrotherm

Hydrotherm is a boiler brand operating as a division of Mestek, a manufacturer of heating and metal forming equipment headquartered in Westfield, Massachusetts. Hydrotherm has manufactured cast iron boilers for more than six decades, having marked its 50th year of production by 2011, and the brand is credited with pioneering the modular boiler concept that influenced how commercial heating systems are designed and installed.

Product Lines

The KN-Series forms the core of Hydrotherm's current condensing cast iron boiler lineup, built for residential, commercial, and light industrial heating applications and manufactured at the ATH facility in Boyertown, Pennsylvania. Hydrotherm also produces the HVX gas fired boiler, which uses an induced draft blower system to vent flue gases rather than relying on natural chimney draft. Across the brand, offerings include gas fired, oil fired, condensing, and modular boiler configurations.

Why Contractors Specify Hydrotherm

Heating contractors working on retrofit and replacement jobs often turn to Hydrotherm because the KN-Series condensing boilers carry a 25 year heat exchanger warranty, a length of coverage that helps justify equipment cost to building owners over the life of the system. The HeatNet electronic control on KN-Series models can modulate firing rate down to a fraction of maximum input, which contractors value when sizing equipment for buildings with variable heating loads. Cast iron construction paired with condensing technology also appeals to installers who want the durability of traditional boiler materials combined with modern efficiency.

How to Choose Hydrotherm Products

Sizing a Hydrotherm boiler starts with a heat loss calculation for the building, since KN-Series models are offered across a range of inputs to match different load profiles. Installers should also weigh whether a project calls for a condensing or non-condensing design, as venting requirements and clearances differ significantly between the two. For buildings with fluctuating demand throughout the day, specifying a model with a wide turndown ratio on the HeatNet control can reduce short cycling compared with a single stage unit.

Frequently Asked Questions

How long has Hydrotherm been manufacturing boilers?

The brand has produced cast iron boilers for more than 60 years, having celebrated its 50th year of manufacturing by 2011.

What warranty comes with Hydrotherm KN-Series boilers?

KN-Series condensing cast iron boilers carry a 25 year heat exchanger warranty.

Where are Hydrotherm KN-Series boilers manufactured?

Production takes place at the ATH facility in Boyertown, Pennsylvania, under Mestek, the parent company of the Hydrotherm brand.

What is different about the HVX boiler compared to a standard gas boiler?

The HVX uses an induced draft blower to vent flue gases, instead of depending on a heated chimney to create natural draft like many conventional gas boilers.

Can Hydrotherm boilers handle buildings with variable heating loads?

KN-Series models paired with the HeatNet electronic control can modulate firing rate down to a fraction of maximum input, which helps match output to fluctuating demand.