In-floor heating: Is it reliable & affordable?
By Amy Newman
If you’ve ever stepped onto warm bathroom tiles on a cold winter’s morning, you know how luxurious radiant floor heating can be. And, believe it or not, it dates as far back as the Romans, who used fires to warm elevated floors. But is it worth it? To answer that question, we turned to the experts to find out what you should consider before adding this little bit of luxury to your home.
Cleaner, comfortable, more efficient heating
“(Radiant floor heating) is your most effective heating system in terms of efficiency,” says Jeff Cooper, president of Central Plumbing & Heating in Anchorage. “It’s approximately 20 percent more efficient than forced air or baseboard heat.”
That’s because unlike forced air or baseboard heating systems, which rely on circulating heated air throughout the house, allowing heat to rise to the top half of the room (where heat loss is greatest), radiant floor heating concentrates heat in the lower half of the room, where it’s needed the most.
In a radiant heat system, heated water flows through a series of thin tubes laid underneath the floor, Jeff says. As the water warms the floor, heat radiates upward, warming every solid object it comes into contact with; those warmed objects, in turn, radiate more heat. The result is a comfortable, even heat that warms the room from the bottom up.
“I would say that’s the biggest advantage of in-floor,” says Scott Allen, general manager and owner of Trailboss Solutions in Anchorage and Wasilla. “(The heat) is more uniform throughout the house. Warm air rises, cool air falls: It mixes and creates a perfect temperature.”
Another bonus? Since no air is being forced through vents, less dust and fewer allergens will be kicked up and circulated throughout the house, he says.
The cost of comfort
Like all luxuries though, radiant floor heating comes at a price.
“Radiant heat can (be) three to four times the cost of a typical forced air heated furnace house,” Scott says.
That extra cost comes from the equipment required to operate the system – tubing, circulation pumps, a grooved subfloor to secure the tubing, a boiler or hot water heater, and thermostats, he says. Even more equipment is needed if you want the ability to vary the temperature among rooms.
Adding radiant heat to an existing home means increased labor costs on top of materials, Scott says. Existing flooring must be ripped out to install the tubing and grooved subfloor (alternately, the tubes can be stapled down), and a thin layer of concrete poured to secure the components, he says.
Installation costs will be slightly lower if there is access beneath the room or rooms where you plan to install the system, such as a crawl space, Jeff says. But without an exposed area – say, if you want to install radiant heat in a second floor bathroom – expect the cost and length of the project to be high.
“You have to either open up the ceilings below or add lightweight concrete (to accommodate the tubing),” he says. “So it’s a major remodel to do it in an area that has finished areas below.”
A more cost-effective option, Scott says, is to install an electric heat mat when remodeling a kitchen or bathroom. The heat mat provides the same effect as a traditional radiant heat system, only with electricity rather than hot water. Your electric bill will increase somewhat, but the cost of labor and materials will be significantly lower, he says.
Factor in flooring
Radiant floor heat can be installed under any type of flooring, but generally works best with solid floors like concrete, wood or laminate, Jeff says. Carpet acts as an insulator and dampens the radiant effect; extra tubing can compensate for that heat loss, but the overall cost will increase.
If installing under wood floors, be sure to check the manufacturer’s recommendations regarding the highest temperature the wood can withstand, Scott says. Exceeding that temperature can cause the wood to shrink, creating gaps or cracks.
Breathe in, breathe out
Because air isn’t being pulled in from the outside and circulated throughout the house in a radiant heat system, air inside the house will become stale if it’s not properly ventilated, Scott says. To create that air exchange, you’ll need to install either a heat recovery ventilation (HRV) system or a fan with humidistat. An HRV isn’t required, but the home won’t be given a 5-star energy rating without one.
Scott and Jeff both say that most new construction uses radiant heating systems. And because forced air heating systems work well in Alaska’s climate, Scott adds, the choice ultimately comes down to personal preference.
“In-floor heating is just nice, even heat. It’s a very comfortable heat,” he says. “If they can afford it, a lot of people will want it.”