As everyone pretty much knows by now, “radiant heating” is an all-encompassing label that casts its shadow over several different schemes of delivering heat to a living space. Today, the two most common types of radiant heating are hydronic and electric.
    Hydronics have a very long history on the heating front, but the New Kid on the Block is electric radiant heating systems. Typically electric radiant systems consist of a flexible mat of material that’s wired into a thermostat. The mat is usually embedded in thin set or other substrate and then the final surface is laid down. Electric radiant systems are most commonly used in "barefoot" areas like kitchens and bathrooms. They are sometimes even installed in countertops, showers and bathtubs.
    Their flexibility and ease of installation has resulted in electric systems racking up a phenomenal increase in market penetration over the past few years. According to research published by the Radiant Panel Association of Loveland, Colo., the industry posted sales of more than 6.1 million square feet during 2006, up from virtually none during 2001.
    A recently constructed custom home in Monterey, Calif., is the recipient—and beneficiary—of both of these popular forms of radiant heat.  

Hydronically Speaking

The crew from Bayshore Plumbing, Walter Crosby, left, partner Matt Belleci, center, and Dusty Faulk, right. Photo courtesy of Bayshore Plumbing.

First, the 3,000 square-foot, two-story home’s hydronic system, as well as its plumbing system, was installed by Bayshore Plumbing of Monterey, where partners Walter Crosby and Matt Belleci have been doing plenty of radiant work of late.
    Crosby said that’s no surprise since radiant heating is very popular in the area, especially in custom homes: “In the nicer homes it’s pretty much the only thing they put in,” he said. “Monterey is a medium climate so it can get into the 50s. There’s always a need for heat. We’re not toasty warm so we kick on the heat in the evening. Right now (early December—Ed.) it’s just starting to get cold for us—it’s getting down into the 40s so you’re using the heat more.”
    Crosby said his involvement with the project was predicated on an existing relationship with the general contractor who, Crosby said, “just naturally called the guys he knew.” After installing the normal plumbing for the building using Uponor AquaPex tubing with copper stub-outs, Crosby’s team got busy with the hydronic system.
    “We’ve pretty much figured out a good streamlined, simple system that’s reliable so we pretty much go that route, “ he said, adding the foundation for the hydronics was ThermalBoard’s modular radiant thermal mass panels and 3/8-inch AquaPex tubing from Uponor.
    Crosby said Bayshore Plumbing created a quartet of manifolds for the project, each about 36 inches long. These were squirreled away in closets and similar out-of-the-way spots with acceptable access for any future repair needs.
    “There’s one upstairs and three downstairs,” Crosby said, adding the home has four zones with hydronic radiant heat. “Then there’s one thermostat upstairs in the master and then three downstairs.”
    Bayshore Plumbing took a somewhat less conventional tack when it came to getting the heat into the system. Instead of a traditional boiler, Crosby said he’s had good luck using tankless, gas-fired water heaters for hydronic radiant chores.   
    “We used the commercial Rinnai model C85-I tankless water heater, he said. “It’s a gas unit. They’ve been great for us. They’re pretty much all we use now.” The company also installed a Rinnai model R98I-0 residential tankless water heater for the domestic hot water system.   
    “That gives more volume for the bathtubs and showers,” Crosby said. “We had technical troubles with some boiler systems and they’re expensive. Tankless water heaters started coming out so we tried one with a small system. That went well so we started using them here and there. We haven’t had one problem—you plug them in, walk away, don’t even look at them again. We’ve been doing that for probably four years now.”    
    He said the hydronic radiant closed-loop system is fed by a Grundfos UP26-99 circulator pump. The tankless heater is set up to put 120-degree Fahrenheit water into the radiant system.   
    Radiant heating of whichever stripe is very popular among the high-end residential crowd in Monterey and environs. And why not? Homeowners love it because of its comfort. There’s also a little “Keeping up with the Joneses” at work as well.            
    “The thing that pushes the radiant heat around here is that it’s the thing to do—just like the latest faucet,” Crosby said. “Everyone’s got to have it. Generally once they get it they want it all the time—they want it in their next house if they ever do another one. It’s a great heat. It costs more to install it but once it’s going it’s great.”

Electric Touches

Electric radiant installation is as easy as rolling the mat out over thin set adhesive. Tile or other flooring materials go right over the embedded matting. Photo courtesy of NuHeat.

This Monterey house features a pair of bathrooms—a master that measures about 60 square feet and a somewhat smaller half bath. The owners decided to have those two rooms heated using electric radiant matting from NuHeat. Jimmy Graham of Graham Tile in Monterey was tapped for the installation.
     "Basically this is a very thin pad that we can put anywhere underneath anything with a limited amount of room and heat the area,” Graham said. “You can adhere the mat to your setting surface and then you can put your tile directly on top of the mat. I just bury them in self-leveling adhesive and it protects them. It’s an alternative that can be incorporated to make radiant work in certain areas where hydronics might not.”
    Nuheat offers some 60 “standard” sizes of matting that can be puzzled together to fit almost any room. In addition, the company will, as in this case, create custom-tailored mats based on a particular room’s contours to accommodate curves, strange angles or other architectural hiccups.
    Even with the custom matting, the electric install wasn’t without a minor “gotcha.” Graham said one of the workers drilled a hole through the NuHeat mats once they were installed.
    “The foreman came and drilled through my marble and got the NuHeat pad because he never knew it was under there,” Graham said. “The company came out and brought a tool that will find a break or a cut. They took out only one piece of tile on either side of that, repaired the pad and put the tile back. That stuff can be repaired very easily because it’s just a resistor wire that runs through there.”