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Hydronic 3 – the pinnacle of development

The effective heat source for motor homes

Hydronic water heaters

An efficient heat source for a diverse range of requirements

The Eberspächer Hydronic water heater is a genuine all-rounder. It can easily be integrated in the engine’s existing coolant circuit, takes up minimal space, and can be used both as an additional heater for the front area and for engine pre-heating as well as for heating the interior via convectors. When used in combination with a boiler, you can also heat the tap water for your shower or sink, for example. Of course, each application can also be integrated in your vehicle as a complete system, for maximum comfort. Why do without the finer things in life when you’re on the road?

The main benefits:

  • Extremely high heating performance up to 12 kW
  • Low fuel and electricity consumption
  • Runs quietly
  • Space-saving installation in the engine compartment or underfloor
  • Can be operated at high altitude  


Please note: Fuel operated heaters are not suited as building heating system but authorized exclusively for the use in vehicles.

The Hydronic 3 – the pinnacle of development

High-tech for high comfort

The Eberspächer Hydronic 3 creates warmth and comfort at a high technological level.

It combines maximum comfort with constant heating performance and low fuel consumption. The heating process is continuously monitored by highly sensitive sensors, and electronically controlled.

In vehicle models with pre-heatable engines, starting is gentler on the engine and is less of a burden on the battery.

Eberspächer Hydronic

How it works

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Eberspächer Hydronic

Installation example

Harnessing the powerful Hydronic S3 coolant heater, the groundbreaking Eberspächer Hydronic AquaSystem redefines the RV experience.  By seamlessly delivering cozy dry heat, on-demand domestic hot water, and the option for adding heavenly heated floors,* the Hydronic AquaSystem more than meets the rigorous demands of the North American RV industry.

Engineered with precision and designed with reliability and safety top of mind, the Hydronic AquaSystem boasts an automatic altitude compensation adaptor, ensuring consistent performance at any elevation. Its sleek and compact design ensures optimal space utilization while the tank-less water heater stands ready to deliver hot water at a moment's notice, granting you the comfort and convenience you deserve.

Unveil a new era of travel with Eberspächer's Hydronic AquaSystem, where every time you step into your home on wheels, it feels like a warm embrace, no matter the season.

*NOTE: Components required for floor heating are not included in the standard AquaSystem kit.


The AquaSystem kit includes:

  • Eberspaecher Hydronic S3
  • 2X water to air heat exchanger
  • Plate heat exchanger for hot water on-demand
  • 4.3" touchscreen controller
  • Exhaust silencer / intake silencer
  • Automatic / scheduled activation
  • Electric heat (1500watts) w/shore power activation
  • Automatic fan control
  • Automatic altitude compensation to 3000 m (app.10,000 ft.)

Hydronic S3 Economy

The most compact water heater, with 4 and 5 kW heating performance: 

  • When installation space is tight
  • Can be used in virtually any vehicle as additional heating for the living area, and integrated in the engine circuit to pre-heat the engine
  • Can be installed in the engine compartment or underfloor
  • Can be combined with convectors and used as an interior heater for camper vans and smaller motor homes
  • Manual high altitude operation over 1,500 m with the EasyStart Pro control unit

Hydronic S3 Data Sheet

Hydronic M

  • Can be used as an interior heater in combination with convectors for larger motor homes with a high heat requirement of 8, 10 or 12 kW
  • Can also be used as a pre-heater or cab/additional heater with engine pre-heating in vehicles with large engines
  • Can be installed in the engine compartment or underfloor
  • Standard altitude capability up to 3,500 m (M10/M12)