Canadian Consulting Engineer

Advocates of hydronics heating say it makes sense for homes

February 4, 2004
By Canadian Consulting Engineer

Following is an article written for the Canadian Institute of Plumbing and Heating that advocates the benefits of h...

Following is an article written for the Canadian Institute of Plumbing and Heating that advocates the benefits of hydronic heating in residential homes.

Hydronic Radiant Under-Floor Heating.
Home Heating for the Future – Today

by Karl Eichner

The Romans used radiant floor heating in their bathhouses and for centuries, the Koreans heated their royal palaces and traditional homes in this manner. Today, an improved version of this technology can be used in all or part of our homes. Radiant floor heating applies heat underneath or within the floor. In the same way that we warm ourselves in the sun’s radiant energy, this type of heating warms objects as opposed to raising the temperature of the air.


There are three types of radiant floor heating – hydronic, electric and air. This article focuses on hydronic (water) heating. Introduced to North America after World War II, hydronic radiant floor heating uses a system of pipes or tubing laid within a floor to carry hot water into specific rooms, dispersing the heat through the floor surface. The cooler water returns to the heat source, where it is reheated and sent out again. The heat output is determined by pipe spacing, water temperature, flow rate and floor covering.

Hydronic heating is available in both new and existing homes. Homeowners can choose to install hydronic radiant floor heating throughout the house, or in selected rooms. This type of heating is especially popular in the bathroom, kitchen and living room areas where people spend the most time. The system can also be "zoned" so that there are temperature controls for each area.

The heat source in hydronic radiant floor heating is a boiler. The energy used to heat the hot water can be natural gas, oil, electricity, propane, wood or solar hot water collection. Pre-set controls dictate how warm or cool a room or area of the home will be. A manifold system with thermostat or aquastat switches operates a series of simple valves that are used to regulate the flow of water through each zone.

Radiant floor heating provides even, draft-free warmth, as there is less air movement with this type of system. The thermal mass (concrete floor) evens out the temperature fluctuations and the floor is warm to the touch.

Radiant floor heating can be more economical to operate because the temperature may be set to 20C (68F) rather than the usual 21-22C (70-72F) as required by other types of systems. The warmest air is at floor level where it is most needed (as opposed to the ceiling) and very little heat is lost through the ceiling and walls. The ability to zone a variety of rooms with customized temperatures has the potential to reduce energy consumption.

The system is quiet because a properly sized circulator pump, used to slowly move the water, is almost inaudible. The loudest sound in the system is usually the gas or oil burner. Unlike conventional forced-air furnaces, radiant floor heating has no ducts to contribute to dust collection or movement. However, ductwork is required for the mechanical ventilation system or air conditioning. For people with allergies, the reduction in dust movement may be very beneficial.

Since hydronic radiant under-floor heating systems are virtually invisible, furniture layout is not restricted by the heating system. Bathrooms or special use areas with hard floor finishes are especially well suited to this type of heating.

More than 100 million feet of pipe is installed annually for radiant heating systems throughout North America in everything from fine art museums to prisons. As green building and products with low environmental impact become increasingly important, radiant heating makes even more sense.

Industry efforts to develop a national standard have culminated in the CSA International B214-01 Installation Code for Hydronic Heating Systems. The standard provides complete guidelines for the installation of modern hydronic heating. This North American "first" was developed with funding and expertise from the Canadian Institute of Plumbing & Heating, the Canadian Hydronics Council, the Alberta Hydronics Advisory Council and the Residential Hot Water Heating Association of BC and will be now referenced in the Canadian Building Code in 2005.

Further information on hydronic heating can be found on the Canadian Institute of Plumbing & Heating web site at


Karl Eichner is President of Karl Eichner & Associates, a Toronto-based communications / media consultancy. He can be contacted at 416-447-2265, or e-mail:


Stories continue below

Print this page

Related Stories