What is radiant floor heating?

Radiant floor heating is a method of heating your home by applying heat underneath or within the floor. Comparable to warming yourself in the sun, 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 About Your House document focuses on hydronic (water) radiant floor heating.

Brought to North America post World War II, the first generation of North American systems met with several mechanical failures. The introduction of carpeted floors reduced the system efficiency. Today, significant improvements have been made in both the heating component and the system design.

Hydronic radiant floor heating is a system of plastic or metal tubes/pipes laid within a floor that carries hot water into specific rooms or “zones”, dispersing the heat through the floor surface (see Figure 1).

The cooler water returns to the heat source where it is reheated and sent out again in what is known as a “closed-loop system”. The pipes can be encased in a concrete slab, a concrete or gypsum cement overpour, laid into thin grooved panels that nail on top of a subfloor, or suspended below a wooden subfloor using metal fins fastened under the floor surface (see Figure 2). The heat output is determined by pipe spacing, water temperature, flow rate and floor covering. The heat output must be calculated to meet the heat loss demands of the home.

One type of tubing commonly used is a new leak-resistant, non-toxic, high temperature, flexible piping called cross-linked polyethylene (PEX). PEX is a durable tubing that doesn’t become brittle over time and isn’t affected by aggressive concrete additives or water conditions. PEX has been used in Europe since the 1970s and was introduced to North America in the early 1980s.

For more information go to:
 http://www.cmhc-schl.gc.ca/en/co/renoho/refash/refash_010.cfm