These tips will help keep the process hassle-free.

Use caution when cutting near heating cables. Photo credit: Danfoss

A number of electric floor heating systems are on the market today, but finding a high-quality product with a straightforward installation process can be like finding a needle in a haystack. This general step-by-step guideline will provide you with the tips and tools you need to ensure a successful and hassle-free installation.

Pre-Purchase Preparation

1. Do your research.Take some time to research the product and the company you are purchasing from. Cutting-edge manufacturers are always working on improving their products to make them the most user-friendly and well-engineered products on the market. Here are a few qualities to look for:

  • An electric floor heating system that is approved by UL, CSA, ETL or other certified, safety-approved agencies.

  • Make sure the system uses twin conductor cables that eliminate the most harmful electromagnetic fields.

  • Programmable thermostats - often available as Energy Star-certified, with a ground fault circuit interrupter (GFCI).

  • Self-adhesive mats.

  • Cables approved for wet locations.

2. Measure and measure twice.Before you purchase your electric floor heating system, be sure to measure the area of the room that needs to be heated. Keep in mind areas such as counters, toilets and sinks will not need to be heated, so ensure they are not included in your measurements.

3. Take resistance readings.Resistance readings are one of the most important steps to be taken in the installation process and should be taken with a digital Ohm meter. The vast majority of companies will require resistance readings to be taken - some require three or more throughout the installation process. Most readings are recorded on the warranty card or something similar in nature.

The purpose of resistance readings is to determine if a break in the cable could have been pre-existing when sent from the manufacturer or created during installation. Typically the resistance reading is compared to a label on the power lead. For most systems, your resistance reading must be within a particular range. If it goes beyond the specified range, it will need to be returned or exchanged.

Tip:You can measure continuity with a continuity tester (included with most systems). If a break occurs, the continuity tester will alert you with a buzz, beep, etc., depending on the system.

4. Select thermostat and determine location for installation.First, determine your line voltage based on the area you want to heat. Most systems currently available on the market are 120V or 240V. Using a dedicated circuit is recommended. You will find a wide range of thermostats on the market, but keep your eyes peeled for one that is capable of measuring floor and ambient room temperature and has energy-saving features such as those that offer 4-event, 7-day programmable or manual options.

You will also need to determine the location of your thermostat. More modern systems have a sensor conduit that protects the sensor. The sensor is connected from the thermostat to the electric floor heating system and is the vehicle that communicates temperature adjustments from the thermostat to the floor.

If there is a problem with the sensor, the conduit is a great feature that protects the sensor and eliminates the possibility of having to destroy the floor and/or heating system to repair the sensor. A number of companies still do not use sensor conduits, which in some cases can create added risk for the owner, who will have to incur additional costs should there be an issue with the sensor.

If your system has a sensor, be sure to notch out a channel deep enough to insert the sensor conduit. Tape up the end of the conduit and remove any debris that was created while placing the notched channel. Install the floor sensor in the conduit. Check building codes in your area to determine if a power conduit is needed. Always install appropriate electrical wire from the power source to the thermostat and follow all codes. A licensed electrician is required for all electrical connections.

Tip:Check to see if the thermostat is Energy Star-certified and if it has a GFCI to protect against electrical shock.

Installation Steps

1. Installation of mat.Simply lay or roll out the mat in accordance with your pre-planned layout. If you have an adhesive mat, ensure the adhesive side of the mat is lying toward the subfloor. If you do not have an adhesive mat, your job will be a little more challenging, so you must be a bit more strategic with the placement of the mat.

Glue, double-sided tape or some other kind of adhesive can be used to secure mats that do not have the adhesive backing already built in. Remember to consult your instruction manual to ensure these items are recommended for your particular mat.

More modern and user-friendly mats can be easily customized right on the jobsite with a pair of scissors. But always remember the rule that generally applies to most heating systems: Do not cut the heating cable.

When approaching a wall or other object, cut the fiberglass-like mesh, twist, turn and maneuver the mat appropriately to avoid the wall or object. The mat can be easily customized along an angled wall.

Consult your instruction manual to determine the best type of subfloor intended for use under electric floor heating systems. Common subfloors generally include plywood and concrete. Generally, the cables on the mats should not be spaced less than 2 inches apart and should never be crossed. Most mats should be installed 4 to 6 inches away from drain holes.

2. Cable vs. mats.Nowadays, most manufacturers offer both mats and cables as part of their electric floor heating product selection. There are differences when it comes to the installation of the actual cable, but you will still need to follow the pre-installation instructions as well as the wiring instructions previously mentioned in reference to the installation of mats.

A few things to keep in mind when using cable (applicable to most but not all systems):

  • Cables come in various lengths and voltages. Common voltages include 120V and 240V.

  • Look for a product that comes with strapping, glue, etc., that will help secure the cables to the subfloor.

  • Cable should be spaced between 2 and 4 inches. Standard recommended spacing is 3 inches.

  • Avoid walking on the heated cables and mat at all times.

3. Installation of thermostat.Most companies recommend leaving the continuity tester connected to the mat power leads until a licensed electrician is onsite and ready to make the termination to the line voltage. Install the thermostat and test the unit once the tiles are firmly set and dry. Please check with the thinset manufacturer for curing time.

This general installation guideline will give you the confidence to install your electric floor heating systems with comfort and ease.

Installation Dos And Don'ts

  • Do not cut the heating cable.

  • Do look for a certified professional to perform the final wiring.

  • Don't drop or place sharp objects on the heating cables.

  • Don't overlap or cross the cables.

  • Don't attempt to repair the cables without the proper repair kit and guidelines from the manufacturer.

  • Do fully read and understand the entire installation manual before installing the system.

  • Do ensure you have a clean and level subfloor.

  • Measurement Tips

  • Choose mats/cables that are slightly smaller than the area you have measured.

  • Selecting a product that has a variety of sizes not limited to predetermined sizing makes for a much easier installation process. It is also important to use mats/cables that have the capability to combine in order to cover larger areas if needed.

  • Systems are now available on the market that are approved for wet locations (i.e., showers).

  • Mat Installation Tips

  • Most modern and technically advanced mats are dual-adhesive in that the fiberglass mesh is adhesive as is the tape on the mat itself. This ensures the mat stays in place when you apply the thinset or self-leveller and makes for a much easier and efficient installation process.

  • There are two common ways to approach the installation of an electric floor heating mat:
      1. Lay the heating system on the subfloor and tile directly over the mat.
      2. Apply the scratch coat on top of the mat before tiling for added protection of the heating cable.

  • Once the electric floor system is laid out on the subfloor, most manufacturers recommend taking a second resistance reading with a digital Ohm meter. Be sure to note all resistance readings.