Unless you live in an older building or house, it’s likely the last time you saw radiant heat was in a grandparents’ home represented by the cast-iron fixture that, on cold days, got too hot to touch.
Those buildings that still have radiators have often kept them only for aesthetics and moved on to some form of forced-air heat. Radiators, it seemed over the past two decades, were considered curious but nearly extinct examples of inferior technology.
As many homeowners are now realizing, the problem wasn’t necessarily with the technology, but in the way it was utilized. Old-fashioned radiators get super hot by using steam created using an oil- or gas-fired burner. The steam travels through the system, circulating inside each radiator, heating the metal and the room it sits in.
Unfortunately, it’s extremely inefficient. Rooms are often either too hot or too cold, and it’s difficult for radiator systems to maintain a consistent temperature throughout a house. Physics dictates that warm air will rise, sending much of a radiator’s heat straight to the ceiling and leaving low-lying areas chilly.
The modern improvement upon radiant heating is to move the heat source from the old-style radiator to a series of pipes or tubes built into a home’s sub-floor. They carry heated water rather than steam, which makes the systems more fuel efficient than both old-style radiators and forced-air heat.
Such a system’s benefits have been known for centuries. The ancient Romans used similar systems in their bath houses. Architect Frank Lloyd Wright installed early versions of the modern system – using metal pipe embedded in the concrete sub-floor – in some of his residential home designs during the mid-20th century. Because they were often embedded in concrete, these systems were limited to single-floor homes and had serious maintenance problems if the pipes leaked or cracked.
Today, however, radiant floor systems usually incorporate either plastic tubing or electrical conductors (usually for smaller areas like bathrooms) into modular panels, which can be installed on top of the sub-floor (or as the sub-floor, in some cases) in traditional multi-story, platform-framed homes.
These systems have several additional benefits to old-fashioned radiator heat. Perhaps the most appealing is that it creates not just a warm room, but a warm floor. Per our physics lesson above, the heat still rises, but it’s rising from the entire floor instead of a single fixture or couple of vents. The result is often barefoot comfort in the dead of winter. Such systems are particularly good for homes with cathedral ceilings, where forced-air heat often goes where it is least needed.
Additionally, new systems are much more compatible with a wide variety of floor coverings, allowing for carpet, hardwood and tile with equal success and efficiency.
It’s obvious the Romans and Mr. Wright had great ideas. It’s just taken this long to truly perfect them.