Before choosing a particular system, the installer or contractor should know whether the customer is looking for supplemental heating or wants to use the unit to heat the entire room, along with what type of floor covering will be installed over it. Heating systems for tile will need to be embedded in thin-set or self-leveling cement, whereas a floating floor system can be installed without it.
According to Russ Dunn, ThermoSoft vp marketing, radiant floor heating systems are available in both 120- and 240-volt models. Both will produce the same wattage density, but 240-volt systems will heat twice the area, making them ideal for larger rooms from 150 up to 300 sq ft. Additionally, systems are available from 7 to 15 watts/sq. ft. Lower wattage products will provide gentle warmth, and higher wattage products are designed for use under tile and stone floors. The most commonly seen systems will offer all-around heating at 12 watts/sq. ft.
He added that an installer will most likely already have most of the tools needed to complete a radiant heating installation. These include aplastic notched trowelfor spreading thin-set over a floor heating mat or cables, scissorsfor cutting the fiberglass mesh in a radiant heating mat or for cutting the film in floating floor systems, autility knifefor cutting the underlayment typically installed with floating floor heating systems, and a hammer and chisel or Dremel-type toolto create a groove in the subfloor for the thermostat floor sensor.
Two specialized tools are also required. An ohm-meter or multimeterwill be needed to check the heating cable resistance periodically throughout the installation, and an installation monitorwill provide continuous monitoring and sound an alarm if the heating system is accidentally damaged during installation.
The first, and most important step is to measure the floor to determine the exact amount of space that will need to be covered with the electric radiant floor heating system. Scott Cook, president of radiant heating systems distributor Warm Your Floor, noted, “You cannot cut away any of the radiant heating system if you over-measure. It has to be exactly the right amount. And if you’re measuring for a bathroom, remember that you cannot put radiant heating behind toilets or under built-in bathtubs.”
Two other steps to follow: Always make sure to install the sensor for the thermostat, and never cut or nick any wire. “The good ones are pretty tough, but a knife or sharp object will cut it, so keep the knives away from floor heating elements, and restrict heavy traffic before the thin-set or tile is put on top,” Cook noted.
Using the digital multimeter is an easy process, he added. “All you need to do is take three readings. When you take the radiant heating system out of the box, you check it. Once you lay it out and before you cover it up, check it again. Finally, after it’s covered, do your last check.”
Romy Sheynis, product marketing manager for EGS Electrical Group, which manufactures the EasyHeat brand, said it is a good idea for installers and contractors to be familiar with their local electrical and building codes before installing radiant heating systems. “It is strongly advisable to check with the local authorities on any regulations pertaining to installing radiant heating systems.” He also said that an anti-fracture membrane is an essential addition for any radiant heating installation that will endure a heavy traffic load or experience sudden changes in temperature or humidity.
The supplier should provide the installer/contractor with an installation manual going over all the details. According to Tom Steffek, DomoTeck Floor Warming Systems’ estimator and technical support, one of the most common mistakes installers/contractors make is not asking for a copy of the manual.
Monica Irgens, president of Electro Plastics Inc./STEP Warmfloor, noted that radiant heating systems need insulation in order to operate efficiently. “If you don’t put in insulation, you’re going to lose a lot of the benefits of the system. People might not be too concerned about efficiency if it’s just a small room being heated, but for large areas, insulation is very important.”
If installed correctly, most systems will raise the temperature between 10 to 15 degrees Fahrenheit above the normal ambient temperature. It can take up to 30 minutes for the floor to warm up, so a programmable thermostat is recommended for areas where the customer expects the floor to be immediately warmed.
Lucas Hann, product application support team lead for Watts Radiant, recommends asking for a heat-loss calculation from the manufacturer. “After the customer submits all the information, the design will be sent back with all the heat-loss information. This is especially recommended for any in-floor radiant products that will be used as the primary heat source.”
When in doubt, call the manufacturer’s technical support line, said Isabelle Marcil, Flextherm Inc.’s communications coordinator. Most problems are easy to fix, as long as all the measurements are accurate. “Results of bad measurements include too much cable, not enough cable, uneven spacing and cold spots,” she noted.
For radiant heating systems that use flexible film instead of a wire system, another common issue is using the improper crimping tool. “Some installers think they can just use pliers or their fingers, but we calibrate our crimping tools in-house. You need to use that specific crimping tool to make the connection,” explained Eddie Gilmartin, CaloriQue’s national sales manager.
Dunn added that one more precaution should be taken when working with radiant heating systems: “Do not lay heating mats too close, as the heating cables will risk overheating. Always plan the layout in advance to prevent over-ordering of material and trying to force it to fit into the available floor space.”
Follow this advice, and installing radiant heating should be a relatively stress-free experience, and especially lucrative during these autumn and winter months.