At bath or shower time, everyone in the family, young and older alike, wants the bathroom to be cosy—and, most important, not too chilly!

Building the heating system right into the bathroom floor is an effective way to enhance the comfort level in the bathroom without encroaching on often-limited free space. All other heating methods reduce available space either on the wall or at the floor edges, limiting your room layout options.

Spotlight on radiant heating


Radiant heating technology draws inspiration from nature, specifically, the way sunlight warms surfaces. Radiant floor heating, also called “underfloor heating,” is the main application of this heating method, although it is also seen in wall- and ceiling-based systems.

Here’s how it works:

  • Heat (infrared) energy radiates from elements under the floor and warms objects, surfaces or people that it comes into contact with. Those surfaces then radiate that heat energy to warm the surrounding air.
  • Interestingly, methods like baseboard heaters, forced-air systems and electric convector heaters work the other way around: they increase the air temperature, which is transferred to surfaces afterward.

 

Advantages that will be warmly welcomed!


The main virtue of radiant heating in bathrooms is comfort. It produces enveloping heat that is felt first by the feet and then travels through the rest of the body—all without air movement, not to mention dust being blown or “toasted” by a heating element.

There are other attractive features:

  • A radiant floor heating system is resistant to water and moisture, because it is buried under the floor covering, which is itself water- and moisture-proof (at least in principle!).
  • The heating elements are built into the floor, so they don’t take up any space in the bathroom.
  • The system is completely silent and maintenance-free. It is controlled by a simple thermostat.

Moreover, generally speaking, other heating systems create “stratified” zones of uneven heat in a room: the air is warmer at higher points, and cooler below. The temperature difference between floor and ceiling can be as high as 8°C! With radiant heating, the temperature is more even throughout the room.

The downside? The cost of installation can make some homeowners wince. For an underfloor system, the bill for both parts and labour will be more expensive than with other types of electric heating, like baseboard or convector systems.

Two types of radiant floor heating

If you’re planning to equip your bathroom with radiant floor heating, the first thing you need to know is that there are two basic types of system.

Electric radiant flooring

This is the most common method when renovating. Systems are designed to go under ceramic or natural stone, but are also suitable with other types of floor covering, including engineered hardwood, vinyl, linoleum and so-called floating floors. A note of caution, however: always check with the heating system manufacturer whether a given floor covering material is compatible.

Technical notes

  • The radiant heating cable must be installed beneath the floor covering, properly spaced using a cable guide. With some systems, the cable comes mounted on a fibreglass mesh.
  • To be used as the main heat source for a bathroom, the system must have radiant power of about 12 watts per sq ft (130 W/m²).
  • Thermal insulation of the subfloor is optional, but strongly recommended for maximum efficiency.
  • For safety reasons, installing a ground fault circuit interrupter (GFCI) is a must.
  • The system must be connected by a certified electrician.


Hot-water radiant flooring


This option, also known as hydronic radiant heating, is more versatile when it comes to the energy source (which can be gas- or oil-fired, electric, etc.).

Water heated by a furnace is pumped through a closed loop of tubing to radiate heat through the home. The tubes used to be made of iron or copper, but these days cross-linked polyethylene tubing (commonly called PEX) is used.

Technical notes

Heat is distributed through plastic tubing built into one or another of the following structures:

  • A concrete slab poured at ground level;
  • A lighter concrete slab, 1.5 in. (4 cm) thick, poured over plywood sheeting;
  • The subfloor, between joists, where access from below is possible.


Whichever system you choose, once your radiant floor heating is installed, all that’s left is to enjoy the extra comfort in the bathroom!