Hydronic heating

How does hydronic heating deserve its own section on a blog titled “Hot Water Thanks to the Sun?” Hydronic systems are designed to heat hot water, as well as radiant heat and other types of residential heating systems. They may or may not include solar.
These systems can include domestic hot water, commonly using an indirect tank.
You may notice that some of the following drawings mention a specific brand. All hydronic equipment, however, is largely adaptable to other manufacturers.


Here are some terms you may encounter. It is absolutely not complete. Hope it’s helpful.

  • Combi: A boiler that creates home heating and has a separate internal heat exchanger to produce domestic hot water, without an external tank. DHW production follows the same principles as a tankless water heater.
  • DHW: Domestic hot water
  • EMC: (Electronically Commutated Motor) pump for variable speed pumping, some boilers manufacturers include the pump internally, or as an accessory.
  • Indirect tank: A tank sized for the home’s hot water needs, that is usually heated by a boiler sending heat to the tank’s internal heat exchanger.

We’ve added a glossary that is absolutely not complete, but may provide a few answers as you begin.