1. Determine Heated Area Square Footage
To determine heated area and square footage of the ThermoTile radiant floor heating mats required, measure the total square footage of the room and subtract the square footage of the non-heated areas. Or, measure only the floor areas to be heated.

For example, in a bathroom, subtract the tub, vanity and toilet areas. In the kitchen, subtract the cabinets, refrigerator, oven, etc. If not heating the whole floor, plan to heat at least the main traffic and living areas where people will be walking, standing or sitting. The heat will only spread 1 to 1.5 inches from the radiant floor heating mat. So, the surface of the unheated floor will be noticeably cold compared to the warm floor. Heating wires spaced more than 3" apart will leave cold spots. On the other hand, wires should not be spaced closer than specificed in the installation manual .

2. Ordering the mats
Go to the "Shop Online" page and select from the various sizes of radiant floor heating mats that will cover the square foot heated area you calculated above.

3. Connecting multiple radiant floor heating mats
You can combine more than one radiant floor heating mat to cover your total square foot floor space. Each radiant floor heating mat comes with a 10' lead wire and the lead wires must be connected together in parallel to the thermostat (white to white, black to black, etc.)

4. Mat width
Note: the actual width of ThermoTile radiant floor heating mats is 15 inches. Since you can leave a 3 inch space between radiant floor heating mats and between mats and walls, we say that each radiant floor heating mat will cover a width of 1.5' or 18 inches. However, when turning a long mat so that it is running parallel with itself, plan on the width of each row being 16.5" on average.

5. Electric Box for Thermostat
Locate the wall where the electric box is or will be placed. We recommend connecting to a dedicated circuit to reduce interference between appliances. If connecting to an existing circuit, make sure the total Amps of all ThermoTile radiant floor heating mats and other appliances connected to the circuit does not exceed the Amp capacity of the circuit. Typical 110/120 Volt circuits begin at 15 Amps although higher Amp circuits, for example, 20 and 30 can be installed.

6. Ordering Thermostats.
Each thermostat will handle several radiant floor heating mats as long as you do not exceed the Amp rating of the thermostat which is 16 Amps. To check this, total the Amps of all the radiant floor heating mats and make sure the total does not exceed 16 Amps. Up to 160 square feet of 120V radiant floor heating mats can be connected to one thermostat.

For areas larger than 160 square feet, you have three choices:

Large Area Choice 1: Use 240 Volt mats to reduce the number of Amps and the number of thermostats required. With a 240V circuit, you can connect up to 320 square feet of radiant floor heating mats to one thermostat.

Large Area Choice 2: Divide the room into more than one heating zone each operated by its own thermostat.

Large Area Choice 3: Talk to your electrician about installing a relay. In this case, the thermostat controls the relay while a relay of the right size, handles the Amps from all the mats.

7. Choosing a manual or programmable thermostat:

Manual: people generally choose a manual thermostat for smaller installations. It has a floor temperature sensor, an on/off switch and a dial for temperature. When leaving for a period of time, you have a choice to leave the setting alone, turn down the temperature dial or switch it off completely. In wet areas such as bathrooms or kitchens, be sure to connect the thermostat to circuit with GFCI (ground fault circuit interrupt). Or, consider purchasing the programmble thermostat that comes with a built-in GFCI.

Programmable: people generally choose a programmable thermostat with larger installations to save energy. The programming function allows for programming up to four "events" per day, 7 days per week where the thermostat will automatically turn on and off or reduce and increase temperature. An added benefit is that a GFCI is built -in to the programamble thermostat.

8. Adding a redundant sensor. Faulty sensors are rare. But, they are hard to replace once installed under the tile. You can install a second sensor as a backup or you can install a flexible tube that will allow you to slide out the old sensor and slide in a new sensor. If you add the redundant sensor, do not connect it. Only connect one sensor to the thermostat at a time. Bring the redundant sensor up to the thermostat box in case it is needed in the future. Weave sensor through the mesh evenly spaced between two heating wires.

9. Choosing Cement
Use a latex modified, Portland cement mortar for laying the tile. Acrylic or other polymer modified mortars are also acceptable.

10. Installing Tile
There are two main methods to install tile:

Method 1 (One Step): Lay the radiant floor heating mats out and attached them to the floor with double sided tape, hot glue or staples. Spread the thin-set mortar with a notched trowel and lay the tile.

Method 2 (Two Steps): Lay the radiant floor heating mats out and attach them to the floor. Cover the mats with a skim coat of mortar by floating thin-set mortar over the mats and screeding it off to create a smooth surface. Let dry overnight. The next day, lay the tile per normal procedure.

11. Grouting Tile
Use a latex, acrylic or epoxy grout for grouting between the tiles. Latex, acrylic and polymers add flexibility to grouts to resist cracking. Epoxy grouts provide high strength, good thermal shock resistance and fast cure. Do not use sharp objects to clean the grout from between the tiles. Most damage to the heating cable occurs when excess grout is scraped away or a tile is removed to be re-leveled and a sharp tool goes deep enough to cut the cable. Call customer service for tips on removing tiles.

12. Other floor coverings (non-nailed down floors)
For all other floor coverings, lay the radiant floor heating mats out and attach them to the floor. Pour self-leveling cement. Lay the floor covering per normal procedure. Limit carpet to not much more than 1/4" thick and use a breathable pad designed for use with radiant flooring. If you do not want to use any cement, check out ThermoFloor, designed especially for floating wood floors: laminates, engineered wood, bamboo, etc. Call for procedures to use with nailed down floors.

13. Ways to attach radiant floor heating mats to the floor -
Staple the fiberglass mesh part of the radiant floor heating mat to the subfloor. You can also use hot glue, double-sided tape or very thin (1/4") strips of duct tape if the subfloor is too hard for staples.

14. If using a metal lath to strengthen your subfloor, make sure the lath is sufficiently covered with a mortar bed (see Example 3) and that no sharp edges of the metal lath are sticking up that could puncture the radiant floor heating wires.

15. Suggestion: Thermosoft provides an electrical radiant floor heating mat monitor that will sound an alarm during installation if the radiant floor heating mat is damaged causing a short or open circuit. Connect InstAlarm™ to your radiant floor heating mats throughout the installation so that you will be alerted to the need for repair should a wire be cut or damaged while tile is being laid.
Make pictures or drawings of the heating mat layout before applying mortar/cement to aid possible troubleshooting.

16. Support
If faxing or emailing drawings to Thermosoft for assistance:
a. Show wall and location of thermostat.
b. Send detailed drawings with dimensions and scale.
c. Include your phone and fax numbers and email address.
d. Fax to 847-279-8845 or email to info@thermosoft.com Attn: Customer Service