Hydronics 101

Water. What do you think when you hear that word? A summertime pool, a nice warm bath, or a tall clear class with ice? Perhaps fun activities come to mind like fishing, skiing, or surfing. Do you ever think about the power of water from bad things like tidal waves to good things like providing vast amounts of electricity (Niagara Falls, Hoover Dam)? The fact is, water is all around us, covering 70% of the Earth’s surface, and it is in us, making up roughly two-thirds of our body’s chemical composition.

Water is the only substance that exists naturally in all three physical states (solid, liquid, and gas) and has the second highest heat capacity of any compound. These properties, and its abundance, make water the influential player in our planet’s outdoor climate and essential to the existence of life. Our planet and the human body use water to heat, cool, and sustain life.

So, when considering how to control indoor climate and maintain occupant comfort, would it not make sense to use water as the primary energy transport medium within a building?

What is Hydronics?

Hydronics is the practice of using water as the primary substance to transfer energy within a heating and cooling system.

While this is a science, it is also an art, as there are a number of different ways to accomplish this. This is where we at Heat Transfer Sales can help. Almost all of the manufacturers we represent and products we promote are designed and purposed for hydronic heating and cooling applications. There is no one way to design a hydronic system for every building. Each structure and situation is unique, and the best system can only be determined by considering all the factors involved.

How Do Hydronic Systems Work?

Let’s think of a building as we would a human body. A body has a heart, stomach, lungs, brain, and other organs that are essential to the various functions of that body.  A building’s systems may be thought of the same way.  A building’s circulatory system is the piping system, with pumps acting as the heart moving energy throughout the building using water in lieu of blood.  

We can carry the analogy further: 

  • Boilers and chillers = the digestive system,
  • Air handlers = the respiratory system, and
  • The brain = building automation system.  
Many of these systems are based in one area, usually the mechanical room, and its functions serve the rest of the building, providing energy, control, and comfort.

Our expertise here at Heat Transfer Sales resides with the application of the equipment that transports and exchanges the energy throughout a building’s systems. We must have a high level of understanding, not only of the piece of equipment that we sell, but how its operation impacts the remainder of the entire building comfort delivery strategy.  To again pull from our medical analogy, most mechanical design engineers may be considered great general practitioners. We at HTS would be the heart specialist, your consultant when special attention is needed in a specific area.

Hydronic Heating & Cooling System. A Common Air (DX or VRF) System?

  • More useable space for your building.  Air requires 100x more space to transport energy than water.  Example: ¾” pipe vs. 10” x 10” duct.
  • More energy efficient, primarily due to the superior heat transfer and physical properties of moving water.
  • Longer equipment life expectancy for the equipment.  Generally, air-side equipment lasts 10-15 years, while hydronic equipment may run for 20-30 years before replacement need be considered.
  • Excellent scalability and controllability for maximum indoor comfort.
  • Safe, as it utilizes the planet’s most abundant life-supporting substance in water.  Systems using refrigerant as the primary energy transport medium run the risk of exposing occupants to odorless toxic chemicals in the event of a leak.
Common objections to hydronic systems

  1. Higher perceived first cost
  2. More difficult and costly maintenance
While hydronic systems may not be the right solution for every building, we will challenge these two objections with innovative hydronic application solutions and simple education, which are discussed throughout this website.


Hydronic Systems Concepts
There are numerous system concepts, applications, and product specific information in other parts of the website to consider when purchasing a heating and cooling system. It’s important to consider your building’s end-use goals and functionality. Let us know how we can help.
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