How to Install In-floor Heating

The idea of in-floor or radiant heating has been around for thousands of years. The Romans used naturally warm groundwater to heat the stone floors in some of their palaces, and even nowadays there are significant advantages to an in-floor heating system.

For example, because in-floor heating doesn't blow warm air into a room, it doesn't stir up allergens or dust, making life easier for folks with breathing problems or on house-cleaning duty. Radiant heat also doesn't pressurize a house the way forced-air heating systems do so drafts will be virtually eliminated.

Two types of in-floor heating systems are in use today: systems using electricity and systems using water or glycol to provide the warmth.

In an electric in-floor heating system, either special heating cables, mats or panels are installed in, on or over a subfloor, and are heated by passing an electric current through them.

A permanent (but costly) electrical in-floor system uses heavy-duty electrical cables running through a poured concrete pad. More commonly, electrical systems consist of a thin electrical mat (similar to a heating pad) either laid in thin-set mortar or simply installed under a floor (usually between floor joists).

Things You'll Need

• Ceramic tile
• In-floor heating grid and thermostat
• Circuit tester
• Thin-set mortar

Instructions

Choosing a system

1. Consider the concrete slab systems if you're building a new house or doing major renovations. In these systems, a large heating cable is wound back and forth through the subfloor and then concrete is poured over it. The slab provides a solid base for installation of ceramic tile or stone that will be heated by the electrical cables.

2. Consider a system made up of electrical panels, mats or foils when you are looking to "spot heat"' or warm a smaller area such as a bathroom or a bedroom. These systems can be laid between floor joists or under ceramic tile floors as part of small home or room renovations.

   Actual installation of any in-floor heating system is manufacturer dependent since there are numerous ways to construct the electrical grids. The following is a general overview for installing an electrical grid laid under a ceramic tile floor in a bathroom, a common in-floor heating application.

Installing a system

1. Determine the area you want to heat and measure it carefully.

2. Discuss the electrical requirements with a qualified electrical contractor. (Systems often require dedicated electrical circuits, and your home wiring may need to be upgraded).

3. Lay the electrical grid down on the floor, cutting it to fit. Take extreme care to cut only the mesh or mat and never the wires themselves.

4. Use a circuit tester to test for continuity, ensuring the wires in the grid haven't been damaged, after laying the mat down.

5. Fasten the grid to the subfloor using a thin layer of thin-set mortar and allow it to set up (leaving the connections for the wires accessible). Then install the ceramic tiles.

6. Run wires from the electrical grid to the thermostat and to the electrical panel.

7. Consider having a qualified electrician connect the installed flooring to the thermostat and to your electrical panel.

Tips & Warnings

• When you are installing the electrical grid, be sure to check for continuity every time you work with it. The wires embedded in the grid are very small and can break easily.

• Electrical heating systems that can be installed directly under a laminate floor or even directly under a carpet are now available.

• Be sure to have a qualified electrician make the connections into your electrical panel.