How to Install Radiant Floor Heat

Installing radiant heating under your floors can be a wise investment.

Getting warmth from an in-floor heat source is an idea that has been around for thousands of years and has recently gained in popularity. A warm floor feels good on your bare feet during the winter, and it helps reduce the dust and other allergens that can be spread throughout your home if you have a forced-air system. Because the heat from the in-floor system rises, it can reduce your energy costs because the floor will help provide heat for the rest of the room.

Things You'll Need

• Electrician
• Hammer
• Chisel
• Vacuum
• Cleansing agent
• Tape measure
• Pencil or pen
• Cable strapping
• 3/8-inch serrated staples
• Heating cable
• Ohm meter
• Cement-based mortar
• Water
• Trowel
• Wood paneling or tile

Instructions

1. Consult with a certified electrician to ensure that you won't need to upgrade the electrical system in your home to handle the extra use that the in-floor heating system will require.

2. Remove the old floor with a hammer and chisel, then vacuum the floor to remove any debris and use a cleansing agent to remove any dirt or grease.

3. Inspect the subfloor and replace any panels that are damaged.

4. Measure the area of the floor where you want to install the radiant heat. Don't include areas under cabinets, sinks and other fixed objects as you won't be installing the heating cable under these objects. Vacuum the floor one more time to remove any debris that might damage the cables.

5. Sketch a rough outline of where the cable will run on the floor, and then install the cable strapping every 30 inches. Attach the strapping with 3/8-inch serrated staples, placing them no more than 6 inches apart and avoiding places where the cable will go.

6. Run the heating cable on the floor, making sure that the cable doesn't touch anything that could damage it, and it's secure in the cable strapping.

7. Connect the leads for the ohm meter to the wires leading from the heating cable (the cold lead conductors) to check the cable for damage. The reading should be between 10 and 250 ohms.

8. Mix up a batch of cement-based mortar following the instructions on the packaging, and apply a scratch coat over the entire floor, making sure that you completely cover the wires. After the first coat of mortar sets, add a second coat on top, and allow that to set.

9. Install the wood or tile surface on the floor.

10. Run the wires from the cold lead conductors to your thermostat and electrical box.

11. Call an electrician to connect the wires to your electrical box and thermostat.

References

• Easy Heat: Warm Tiles--Architect's Specification/Application Guide
• One Project Closer: How to Install Electric Radiant Heating Wire on a Cement Slab
• Home Heating Systems and Solutions: Underfloor Heating--Why It's Good
• The Family Handyman: How to Install In-Floor Heat
• InFloor Heating Systems: Installation Instructions for Infloor Electric Cable Sets