Electric Radiant Heating Use and Installation
It’s a growing solution for comfort warming
Why should plumbers be looking at electric radiant heating? After all, plumbers and hydronic heat sound like a more natural fit. One good reason is that plumbers and contractor are adding extensive kitchen and bath remodels to their projects list and these residential customers like the idea of floor and countertops equipped with comfort heating. Another factor, there’s a growing list of electric radiant solutions for small spaces and areas where access is limited.
Electric radiant heat may be installed in new construction or as part of a remodeling project for a bathroom, kitchen, entryway, or other room where comfort warming is desired, said Shelby Hyatt, product manager, Watts Radiant. “Watts’ SunTouch has a wide variety of products that will fit the needs of both new and retrofit applications. Our UnderFloor mat, for example, is a great option when a homeowner requests floor heating after the floor covering has already been installed. With UnderFloor mats, you can simply install the mat underneath the floor in the joist bay of an unfinished basement or crawl space.”
“We normally see electric cable installed in both new construction and remodeling projects where they are replacing the floor covering with some type of tile or stone product, agreed Michael E. Willburn, president, Infloor Heating Systems. “We also see quite a bit of our product used in retrofit applications as long as the customer has the available electrical power source. The existing 120-volt circuit can be used if the breaker is changed to a 20 amp breaker and the floor square footage is not too large. If it is a small bathroom these systems can be installed quite easily.”
Small areas are excellent for electric radiant heat, as are homes and structures without the space for a boiler room, said Kyle Stubbs, spokesman for Heatizon Systems. “Electric systems require very little space for the controls, which are often mounted in a garage or attic space. One area where our specific systems really shine is installation beneath nail down hardwood floors. ZMesh is designed to be installed directly under floor coverings, without being embedded in mortar. The unique design of the mesh allows hardwood, carpet and other floor coverings to be installed right over the top. Installers can nail or staple right through the ZMesh as they install the floor covering. With cable or hydronic systems, a nail in the wrong space leads to expensive and costly repairs, making many floor coverings impractical for use.”
What surfaces can you heat?
When it comes to floor surfaces and countertops, most anything can be heated with the right product, Stubbs said. “We often find people pick their heating system first, and then are locked into finding a floor covering that will work with that system. If you have a particular surface in mind, we recommend planning ahead by choosing the best system to work with that flooring. The systems we provide offer a great deal of flexibility, but even within our range of products, there is some variance as to what we would recommend for the best results in various flooring types.”
“There are many types of floor coverings that can be used with an electric cable heating system, including stone, tile, marble, and some laminate floor,” Willburn agreed.“Countertops are a great application when they are concrete or stone. The cable must be embedded in a mortar bed under the counter top for it to work properly.” Watts Radiant’s SunTouch can be installed under a variety of floor coverings including but not limited to tile, stone, laminate, linoleum, vinyl, engineered hardwood, and carpet as long as the heating element is embedded in a cementious material, Hyatt added.
Can we talk safety?
Question one from consumers often is: “Can you safely install electric radiant in wet spaces like bathrooms and kitchens?” How can the plumber/contractor/installer alleviate these concerns? “Electric radiant is perfectly safe for installation in bathrooms and kitchens,” Stubbs said. “In addition to being embedded in the flooring material, line voltage systems will be installed with a GFCI breaker for extra protection. The unique low-voltage systems we install are listed to UL standards for installation in even wetter areas like shower floors and benches. These systems perform effectively and without issue in these installations.”
SunTouch TapeMat and WarmWire cables are waterproof and UL listed for installation in a wet environment such as a shower floor or shower seat, Hyatt said. “For additional safety, SunTouch heating wire is fully grounded from end-to-end and uses a ground fault protected SunStat control.”
“All of our Electric Cable products are rated for installation in wet environments,” Infloor’s Willburn said. “The cable has a W on the UL tag indicating that it can be used in wet environments. We also recommend that when using our electric cable in a wet environment that this be a dedicated cable for this application. We also require that the factory splice (the connection between the power leads and the heating cable) is located outside the shower area at least 1 foot away from the shower opening and other similar areas normally exposed to water.
“Thermostats are also installed at least 4 feet away from the shower opening so that it cannot be exposed to water or be touched by a person in the shower area. It is important to ensure the cable is not damaged during the installation process, and if it is nicked or damaged, to replace it with a new cable. If our installation guide is followed for wet installations then the installer and home owner should feel confident that there will be no safety issues with our electric cable system.”
Electric versus hydronic
Are there projects where electric radiant is an equal or better choice than hydronic radiant? “Depending on your application, smaller projects and projects in regions where electricity is less expensive are ideal for electric floor warming, Hyatt said. “In some cases, electric elements may provide enough heat to become the primary heating source (Heat losses are required in order to ensure proper loads). For primary heating in homes of 1,500 square feet or more, it may be more cost effective to install hydronic radiant heating, depending on fuel source requirements and local cost. Watts Radiant/SunTouch provides a technical services department that can help homeowners and installers decide which option is best.”
Small areas are excellent for electric radiant heat, Stubbs said, “As are homes and structures without the space for a boiler room. Electric systems require very little space for the controls which are often mounted in a garage or attic space. One area where our specific systems really shine is installation beneath nail down hardwood floors.”
“Yes, there are projects where electric radiant heat is far superior to hydronic radiant,” Willburn said. “These types of systems are often installed in just small areas like a bathroom, kitchen, and entryway. Many homes across the country are heated by forced-air systems, and do not have the infrastructure for a hydronic system, and often require cooling. These types of projects are ideal for electric radiant heating.”
Installing electric radiant
“Before installation begins, decide on the goal of the system, Stubbs said. “Are you heating the entire space or just warming the floor? This helps in the design and layout as well as the selection of the product. It’s also a good idea to determine the activation device to be used and plan locations for sensors and thermostats.
“Power is then brought to the needed location, and the heating element and any sensors can be installed. The system should be tested at this point to ensure everything is functioning as intended. Then the floor covering can be installed, followed by an additional test. Finally the activation device is installed and all connections to controls and power are made. The system can then be started up and used. This is fairly generalized; there may be slight adjustments for different applications and flooring materials.”
There are five basic steps in an electric floor heating installation, Watts Radiant’s Hyatt explained.
Electric Floor Heating Installation
- (1) Measure the heated area needed and multiply this area by .9. This total heated area will be used to choose the size of TapeMat or WarmWire product needed.
- (2) Clean the subfloor and attach the SunTouch product. If using a TapeMat, the double-sided tape attached to the mat is adhered to the floor. If using WarmWire, CableStraps are attached to the floor and used to secure the heating wire in place.
- (3) Install a floor sensor in between the heating cables.
- (4) Apply thin-set.
- (5) Install tile.
“There are several steps to installing electric cable,” Willburn explained.
Electric Cable Installation
- (1) Determine the size of the area for the cable installation taking into consideration that the cable will not be installed under any cabinets, vanities, tubs, and closet areas.
- (2) Determine the voltage the customer wishes to use for the system. Many times these products are being installed in a retro-fit application in which they already have an electrical circuit in the area that can be used for the system. In new construction homes we normally recommend using a 240 volt system because it has a better operating efficiency than 120 volt.
- (3) Cable selection.
- (4) Roughing in the electrical box that will hold the thermostat and the electrical wiring connections, and roughing in the sensor tube (Infloor uses a sensor tube to house the floor sensor for easy replacement).
- (5)Test the electric cable with a voltage meter to make sure the cable was not damaged in shipment, and record these voltage readings in the installation guide for the warranty.
- (6) Install the electric cable down by securing it to the floor with metal strapping, keeping the cable 3” from any objects on the floor such as walls, tubs, cabinets, and toilet. Make sure the cable is installed at least 6” from the bowl wax for the toilet. After the cable is installed a voltage reading should be taken again to make sure the cable has not been damaged during the installation.
- (7) Install the flooring in thin set, thick set, or mortar and follow the guidelines of the Tile Council of North America. After the flooring is installed the cable should be tested again with a voltage meter and recorded in the installation guide for warranty purposes.
- (8) Connect thermostat to the wiring and wait for 4 to 6 weeks to allow the flooring system to totally cure prior to bringing the system on line.