Electric radiant: Radiant heating doesn’t always mean a full-blown wet system
Electric radiant. It’s the right technology for some interesting spaces.
“As floor heating grows more affordable than ever, and electric radiant offers an efficient eco-friendly solution, homes and businesses are adding these systems,” said Kyle Stubbs, communications specialist, Heatizon Systems. “Snow melting and roof de-icing also are gaining popularity for homes and businesses seeking to improve safety and convenience.”
Out-of-the-ordinary electric radiant projects include heating reptile rocks at the zoo and warming alligator breeding ponds, as well as dog runs, motor homes, concrete benches and greenhouse planter boxes.
“Electric cable system installations are more common in residential applications for floor warming; however we have seen the use of electric cable for snowmelt applications in commercial projects, as well,” said Michael E. Willburn, president, Infloor Heating Systems. “We have seen electric cable used to heat the shower floor as well as the seating benches in the shower. We have even seen our cable system used in outdoor patios for space conditioning or patio warming in some of the southern climates, mainly just to take the chill off of the stone surfaces.”
Electric radiant is gradually becoming more accepted, so there’s some growth, added Rich McNally, Eastern region sales manager, Watts Water Technologies. Managers of higher-end hotels are now specifying it for bathrooms and showers. Corporate centers are catching on. “And, for homes – sure, it’s happening, but not yet at the levels we were seeing seven or eight years ago.
“I was especially interested in seeing my first kitchen counter top-warming application, and shower heating, too. Another interesting use of electric radiant is in the joist bays from below a subfloor – very similar to the application of heat by the use of tubing to convey heat for a for a hydronic radiant install. Watts was quick to spot the opportunity; their under-floor HeatWeave product is designed specifically to do this.”
Reeves Journal: Is electric radiant still considered a solution for small spaces like bathrooms?
Heatizon: Electric radiant is an excellent solution for small spaces. Heatizon manufactures Floorizwarm, a low-voltage cable system designed specifically for areas ranging from 15 to 110 square feet. This product was designed with bathrooms and other small spaces in mind and provides low voltage comfort and efficiency. Line voltage mats like our Heatwave products are particularly popular with DIYers performing bathroom remodels and make it simple to add radiant heat to any project.
Infloor Heating Systems: Electric cable is still a great product for small spaces like bathrooms, kitchens, and entryways. It also is a great choice for anywhere tile, marble and stone surfaces are used.
Watts Water Technologies: Yes, it’s well suited for that, especially for homes and businesses that may not already have hydronic systems in place to provide the warmth. The systems are amazingly easy to install and are often used for floor warming, to take the chill out of an otherwise luxurious tile or stone floor. The systems can also be used for supplemental heat, or even as the primary source of heat.
RJ: Where does electric radiant work as well or better than hydronic radiant? Why?
Infloor: Electric cable systems work as well or better than a hydronic system when remodeling projects come into play, such as when you are replacing the tile in an existing bathroom on a concrete slab, where there is no room for the mechanical system required for a hydronic system or the floor height to install a typical hydronic radiant floor system. Other examples might be where the project requires more of a cooling load than heating and the customer only wants warm floors in specific areas of their house.
Heatizon: Heatizon believes electric radiant to be superior to hydronic in every application. Electric radiant works far better for roof de-icing as it is easier to install and maintain, and requires less accommodations when roofing. Electric radiant has made great gains in floor and space heating use. Products like ZMesh that can be installed easily under hardwood, carpet and other floor coverings without worrying about nailing through hydronic tubes give electric systems an edge. For small areas, renovations and DIY projects electric mats and free flowing cables are easily added.
As altitude impacts boiler efficiency, electric systems run at 100 percent efficiency. Electric radiant also provides an even heat, where hydronics fluid cools as it circulates away from the boiler. Another factor is the controls involved. Electric systems require small control units that can easily be installed in crawl spaces, attics, garages and other locations.
Watts: Electric radiant is ideally suited for spot warming, especially where there currently is no source for hydronic heat. Some home and building owners prefer the simplicity of electric radiant — no circulation of fluids or equipment to maintain. It works just as well and is as comfortable as hydronic radiant, yet when the cost of operating a large system is compared — looking at electric or hydronic — hydronics typically wins for energy efficiency. Come to think of it, electric radiant heat makes sense in every home in America.
RJ: What’s the protocol for sizing electric radiant to a space?
Watts: Mostly, mats are preconfigured — and that’s to the advantage of installers, for sure. A lot of work goes in to a system design, for instance to determine a layout for electric radiant mats using a home, or room’s, exact dimensions. These layouts consider point-of-entry for the electricity (also, where the thermostat is), location of the thermostatic sensor, room layout to include, for instance, placement of a kitchen island, and finally the point of a mat’s termination. Watts does this layout for installers, making the job a whole lot easier. Yet, there is still some flexibility with the actual layout. The heating element can be separated from the mat if need be, and moved in a different direction, as long as the element itself isn’t cut.
Infloor: Normally when sizing electric cable systems we need to get some information from the customer. Is the application 120V or 240V? Is the application on top of a concrete slab or a wood subfloor with insulation under the subfloor? How many square feet is the application? What type of floor covering will be used with this system?
Once we have all the information, the system is quite easy to size based on cable spacing and watts per square foot. We use a cable product that is not attached to a mat, this makes our system quite easy to install in all types of room configurations without having to order a particular sized mat.
Heatizon: This depends on the product being used. Our low voltage Tuff Cable, Floorizwarm, and ZMesh are all cut to length in the field. However, it is still important to plan ahead to ensure appropriate controls and properly sized transformers are provided for the space being heated. Most of our line voltage products come with factory connected cold leads (the non-heating cable that brings power to the system). While these cold leads can be cut to fit, the heating element cannot. However, we carry a variety of cable and mat sizes and a solution can be provided tailored to any space.
RJ: How common is electric radiant for snowmelt in the West?
Watts: Well, I first want to point out that radiant heat and snowmelt are two different things: radiant heat emits radiant energy to interior spaces, while snowmelt systems conduct or move energy to the snow and melt it. But, beyond that distinction, the answer is that – from our perspective – most of the snowmelt systems in the West are hydronic because of their size, and the BTUs needed to do the work, yet, there are some electric snowmelt systems used for small, medium-sized and larger applications.
Infloor: Electric cable used for snowmelt systems is typically used on smaller space applications such as patios or front walkways. The total amp draw for these types of systems will sometimes prohibit the use of this product on larger applications. The consumer may not have a large enough electrical service to handle large systems.
Heatizon: In the West, we have seen a lot of use of snow melt and roof deicing systems for homes and businesses. One factor fueling this is the trend of “aging in place.” As retirees are living independently for longer, heated driveways and sidewalks are an excellent addition for safety and convenience. In mountainous areas, many homeowners find themselves unable to get up steep driveways in the winter months. A snow melt system, even if it is only a set of tire tracks, provides access that would otherwise be very hazardous.
When it comes to snow melting, you can’t beat electric radiant. Where hydronic systems require semiannual maintenance to start up and stop the system, electric radiant requires none. An electric system is either on or off, it doesn’t idle all winter. Like floor warming and space heating, boilers decrease in efficiency as altitude increases, making an electric system preferable. The even heat of electric systems is also preferred for an even melt. Another factor is the controls involved. Electric systems require small control units that can easily be installed in crawl spaces, attics, garages and other locations. Boiler rooms take up space and are harder to add at a later date.