How to Install Under Floor Heating

Underfloor heating systems are rapidly becoming more and more popular in today’s modern world. Hidden beneath the tile, wood or carpet over your floors, underfloor heating systems can reach temperatures of 80°, radiating up to the living space to keep your feet warm when it’s bitter cold.

But something you may not know is that there are two options when selecting an underfloor heating system.

Heating Mats

The Types of Underfloor Heating

Mat system is a pre-lined mat that spans the same area of your floor. The mat is lined in rows with pre-spaced heating cable, approximately 3 inches apart, for easy installation. This system is ideal for square or rectangular rooms.
Cable system, which comes wrapped on a spool, allowing the installer to unroll the cable and lay it back and forth in rows as needed, also 3 inches apart. This system tends to be more convenient for rooms that aren’t square or rectangular, and installers have the ability to place the cable as needed.

Installation Tips

Mat system:


Step One: Measurements

  • Measure the area receiving the mats, exclude the furniture.
    • The heating cable must be at least 3 inches out from the wall.

Step Two: Sketch Out Your Laying Pattern

  • Plan your installation to make sure that all the black power cables end at one junction box

Step Three: Prepare the Floor

  • Subfloors that have a rough finish should be leveled using a suitable leveling compact
  • It is strongly recommended that insulation mats be installed for energy efficiency
  • Make sure the surface receiving the heating mat is smooth, dry, and clean.

Things to Know!

  • The heating cables should never cross each other!
  • The heating cables should never be cut!
  • The heating cables should never cross the floor probes!


Step One: Double check your materials

  • Make sure that you have the proper size heating mat
  • Thermostat with floor probe
  • The proper length of protective conduit for the floor probe
  • Check the resistance of the mat wires to ensure that it has not been damaged

Step Two: Unrolling the Mat

  • Unroll the mat as planned
  • When you reach the wall, simply cut through the backing mat (taking care not to cut through the wire!) and turn it at a 180° to unroll it in the opposite direction
    • Be sure that the cable wires are at least 3 inches apart at all times
  • When satisfied with the mat layout, recheck the cable resistance to make sure that it hasn’t changed
Heating Mats

Step Three: Secure the Mat

  • Secure the matting with either tape or a staple gun
    • Securing should be done one the matting mesh, NOT on the heating cables!
  • It is recommended that the edges of the mat be secured so that they do not lift

Step Four: Install the Finished Flooring

  • Cover the floor with an appropriate leveling compound
  • Lay your finished flooring
Heating Mats

Step Five: Install the Thermostat

  • Do not turn on the heating system right away. Contact your provider for the proper drying time. (usually two weeks)

Cable System:

Step One: Prepare the Surface

  • Make sure the surface receiving the heating cable is smooth, dry, and clean.
  • Paint the subfloor with the primer and leave it to dry

Step Two: Measure the Floor

  • Mark the start point as close as possible to the power supply
    • The heating cable must be at least 3 inches out from the wall
  • Mark the outer corners of the heated area and connect them to make the perimeter
  • Mark the spacing intervals along the perimeter (3 inches apart)

Step Three: Laying and Securing the Cables

  • Once you’ve tested the area, lay out and secure the cable in the marked places using tape and/or hot glue
  • Space cable 3 in. apart – never overlap the cable
  • Keep cables 3 in. away from walls, showers, tubs, toilets

Step Four: Wiring

  • Set up the wiring to the thermostat—we recommend consulting an electrician for this portion.

Step Five: Finished Flooring

  • Install your flooring over the cable configuration.
  • Now you can complete the wiring. – Again, we recommend consulting and electrician.

How much underfloor heating cable do I need?

Heating Cables

The amount of heating cable needed really depends on the size of the room you are trying to heat. To calculate how much cable you need follow these steps:

  1. Measure the length and width of the room and multiply them together to find the area.
  2. Calculate the unheated area by finding the area of the permanent furniture (cabinets, baths, etc.).
  3. Subtract the unheated area from the total area
  4. Then subtract an additional 10% to allow room for the 3 inch border around the wall. This final number will be the total heated area.

Once you have the total area to be heated you can find the amount of cable you will need. Conveniently, most heating cables are marked with the area they cover not with the length of the cable but, just in case they are not marked this way, there is a simple formula to help you figure it out.

For a wire that requires 3 inches of spacing, on average 3.5ft of cable is needed for every square foot to be covered.

  • For example: a 12 foot area would need about 40 feet of heating cable. (12 x 3.5 = 42)

For a wire that requires 4 inches of spacing, on average 2.6ft of cable is needed for every square foot to be covered.

  • For example: a 12 foot area would require about 30 feet of heating cable. (12 x 2.6 = 31.2)

Find both Heating Cables and Mat Heating Systems at HomElectrical! Happy Heating!

Wattson Lumen
Wattson Lumen

Certified receptacle. Amped up electrical supplies enthusiast. International Popstar and unqualified lifequard. Wattson prefers to lighten your day with humor and led lights (Just don't ask him to jump in if you're drowning).

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