Radiant-floor heating is a technology as old as the Romans, who channelled hot air beneath their bathhouses and villas.

Thousands of years later, however, it still hasn't caught on in North America in a big way, although that's beginning to change, says Jason Bourque, a program manager with the Toronto-based Canadian Institute of Plumbing and Heating.

"Radiant-floor heating, and hydronics in general, is a growing market in all of Canada," says Bourque, who is also manager of the Canadian Hydronics Council, which promotes hydronics or the science of space heating via hot water conduits.

"Air conditioning was a luxury 20 years ago, but its popularity has now grown so it is almost a staple in Ontario. I would argue hydronics is following the same trend."

Larry MacDougal, Business Edge
Nu-Mun Contracting Ltd. president Doug Muncaster has his radiant-floor system ready to deliver efficient heating.

While radiant-floor heating first appeared in North America as early as the 1930s, the last five to 10 years have seen a significant increase in popularity, Bourque says. According to the U.S.-based Radiant Panel Association, sales of radiant-heating equipment have increased significantly in recent years.

For instance, North American sales of hot-water, radiant-floor tubing rose nearly 40 per cent over the previous year to a total of about 100 million metres. Since 1995, sales have increased an average of 10 to 15 per cent per year.

Part of that growth is due to an increase in the scope of radiant floor-heating application, says Wayne Langford of Design Air ClimateCare.

Unlike older systems that typically heated one or two hard-to-heat rooms, more and more customers are choosing systems that encompass entire floors of a home.

"We have seen just exponential growth," says Langford, whose Thornhill, Ont.-based HVAC company installs radiant floor heating systems. "There is hardly a custom-home project that we do today that doesn't have radiant-floor heating in it in one shape or another."

Essentially, radiant-floor heating works by turning the floor of a room into one large radiator.

In hydronic systems, hot water from a central heat source flows through flexible tubing that zig-zags its way beneath or within the floor.

Typically, the tubes are laid within concrete or light-weight gypsum sub-floors, but it can also be installed beneath hardwood or carpeted floors. With electric systems, a lattice of wire filaments provide the heat source.

In either system, the heat radiating from the floor transfers to surrounding surfaces, which act as a heat sink.

The result is a gentle, evenly distributed heat that trumps traditional forced-air furnace systems, says Robert Bean, president of Calgary-based HealthyHeating.com.

"Forced-air heating is really a brute force way to create comfort," says Bean, whose website educates consumers and builders on the benefits of radiant-based heating, ventilation and air conditioning systems.

"Our bodies exchange heat through radiation and we try to counteract that by raising the air temperature. What you end up with, though, is a totally uncomfortable space. The hotter the air and the taller the ceiling, the colder the floor and the more uncomfortable you become," he says.

In addition to providing superior comfort, radiant flooring also tends to be more sophisticated and flexible than traditional heating, says Doug Muncaster, president of Calgary-based Nu-Mun Contracting Ltd.

For instance, radiant flooring can be zoned to accommodate time-of-day needs or desired comfort levels.

"That's the beauty of in-floor radiant," Muncaster says. "You could build a 2,000-sq.-ft. house with 12 radiant-heated rooms. Conceivably, I can equip each room with its own valve and thermostat, and you could you make every room a different temperature."

According to Ron Robinson, president of Atlas Robinson ClimateCare of Burlington, Ont., modern radiant-flooring systems are relatively maintenance free and have long life expectancies. He adds that since hydronic radiant floors have few moving parts and circulate the same mixture of water and rust-prevention additives, boilers can last for 40 to 50 years.

"And the special cross-link polyethylene or PEX tubing that's used today is projected to last hundreds of years," he says. "Unless somebody comes along and drills a hole in them, they will probably last for the life of the building."

Radiant flooring also tends to be more energy efficient, says the CHC's Bourque. Over the lifetime of an in-floor heating system, customers can expect to pay less to heat their homes compared those relying solely on forced-air systems.

"Today's residential boilers can give you up to 96 cents worth of heat for every fuel dollar," he says. "That's 15 to 20 per cent more than some current heating systems. For commercial applications, the savings can be even greater."

With all it has going for it, radiant-floor heating may seem like a slam dunk. The downside, however, is cost. While radiant flooring may be less expensive to run, the initial installation expense can push in-floor heating beyond the budgets of many homeowners.

"The costs are coming down comparatively, but radiant heating will still always be the more expensive heating system," Muncaster says. "But as the technology improves, the cost comes down and people become more aware of what's out there. The industry's growth will accelerate."

Cost estimates vary from source to source.

According to the Canada Mortgage and Housing Corp., radiant flooring runs between $6 to $8 per sq. ft., but most contractors refuse to ballpark the expense of a typical project.

They are careful to point out that each installation comes with its own unique requirements and challenges, which can not be figured into a generic estimate.

"We have some projects that we can get below $5 per sq. ft., but that's only in the case of new construction where we would be using the existing hot water heater as the heat source," Robinson says. "If you add in dedicated heating equipment, the valves, the pumps and the controls, then you could be up to $7 to $10 a sq. ft. It all depends on what else is going in and how sophisticated the system will be."

The cost factor, he adds, is the reason why radiant heating is seen predominantly in retrofit projects and custom homes.

New home builders are reluctant to increase their building expenses.

"The uptake of radiant-floor heating is driven by homeowners looking for quality comfort rather than homebuilders driving into the market," Robinson says. "Builders reluctantly provide it if the homebuyer insists on it."

Another limiting factor, says Nu-mun's Muncaster, is a lack of awareness among engineers and contractors who may shy away from technologies with which they're not familiar.

"There are a lot of contractors who are stuck in the Stone Age in terms of radiant-floor heating," Muncaster says. "They haven't kept up with the technology, but there is a lot of good technology out there now that makes installing hydronic flooring pretty much idiot proof.

"Radiant flooring today encompasses only about three per cent of the market," Muncaster says. "That's probably $1 billion a year, but it still has long way to go."

(Mike McLeod can be reached at mcleod@businessedge.ca)