by Ali Kriscenski


HVAC systems depend on efficient transfer of energy from a main source, such as a furnace, throughout a building or facility via a transfer medium. A hydronic heating system uses water as its medium, providing excellent energy transferability, thermal comfort and a cost-effective heating solution. Here’s a look at how hydronic heating systems work and the benefits it can bring to your building or facility. 



What Is Hydronic Heating?

The concept of hydronic heating was first widely used in the steam-based systems found in many 19th century homes. Most Americans are familiar with the freestanding cast-iron radiators that hold steam heat energy and ‘radiate’ warmth into living spaces. Today’s hydronic heating systems implement the concept of radiant heating but with more integrated systems that are safer, energy efficient, and provide consistent thermal comfort.


Today’s hydronic heating systems use hot water or an alternative liquid to circulate heat through a building via plastic tubing. The tubing can be installed under flooring, in walls, or even in ceilings, with floor level installations providing the most efficient energy transfer. 



Benefits of Hydronic Systems

From the perspective of occupant comfort, hydronic heating systems provide clean, consistent radiant heat. They eliminate the issues associated with blown air heating such as transference of allergens and debris, and help better maintain parameters for optimum temperature and humidity control


From a building operations perspective, hydronic heating systems can be more efficient, durable and cost effective than hot-air heating systems. Hydronic systems typically have less mechanical components and devices, making routine maintenance less involved. 


What Applications Work Best for Hydronic Heating?

The type of heating system that’s right for your building or facility depends on a multitude of variables, including the type of construction (ground-up or renovation), structural components, finish materials, layout, occupancy levels and program. With new construction, hydronic heating can be considered from a whole building design perspective and integrated with different heat sources, such as geothermal, to optimize energy performance. 


Whether new construction or renovation, the choice to use hydronic heating depends on how well integrated the system can be installed to operate efficiently. Tubing can be installed in concrete floors and walls, which provide excellent heat transfer. The tubing can also be installed between subfloors and finish materials, such as hardwood, stone or tile. The types of finish materials play a significant factor in the effectiveness of the system’s heat transfer and the thermal comfort of occupants.


Finish Material Selection and Hydronic Heating Systems

The thermal properties of finish materials determine how well heat is transferred. Materials like fiberglass have low thermal conductivity, making them a good choice for insulation applications. Flooring like carpeting also has low thermal conductivity, and depending on the carpet thickness and the carpet pad density, this finish may not be an ideal selection to couple with hydronic heating. Better material choices include stone, concrete, ceramics and hardwoods.



Ceramic and stone tiles have excellent heat-transfer properties and are durable materials. Polished concrete flooring is also a good choice with hydronic heating, providing good heat transfer as well as heat storage properties. With both options, the thickness of the material can impact how quickly a surface warms up and typically shouldn’t be more than a 3/4-inch profile. Hydronic heating can be used with hardwoods and certain carpeting as well, but with less heat-storage capacity. The best approach is to consult your HVAC professional and discuss the best finish options to pair with the hydronic system.


Choosing the Right Heating System

Today’s heating and cooling systems utilize decades of building systems knowledge to provide energy- efficient options for all building types. Hydronic heating systems, which provide radiant heat, are energy- efficient and offer high thermal comfort levels for occupants. If you are considering if hydronic heating is right for your building or facility, consulting an expert can help provide the insight and expertise to make the right choice. Therma’s team of HVAC professionals can assist with your long-term energy strategies. Contact Therma today to learn more.


​​Ali Kriscenski was trained in high-performance building design at Boston Architectural College. She has worked with leading architecture and construction firms in NYC and New England and served on the executive team at the Forest Stewardship Council International. She was the managing editor at Inhabitat and has worked pro bono for the Green Building Institute, ISEAL Alliance and Habitat for Humanity.



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