Radiant History

Radiant floor heat was the first form of central heating used by humans. 2000 years ago, the Romans heated villas and baths by directing flue gases from fires beneath stone slab floors. Just as the sun or a crackling fire warms us on a cold day, the radiant heat felt directly by the skin from the warm floors allowed wealthy Romans to feel warm and comfortable with relatively low ambient air temperatures.

Radiant heat was rediscovered early in the twentieth century. Typically, it mimicked the Roman method. But instead of directing flue gases under stone slabs through masonry floor structures, hot water was directed through iron or copper pipes in masonry floor structures, which in most cases were concrete slabs. Frank Lloyd Wright specified this method of heat in many of his designs. Thousands of tract homes were built at Levittown on Long Island and in the San Francisco Bay area during the 1950s using steel or copper pipes embedded in slab on grade floor systems.

These systems earned a reputation for comfort and efficiency. It was also quiet, all but eliminating drafts and reducing dust and other pollutants. Unfortunately, many of these systems failed, as pipes corroded or cracked inside of the slabs. Repair of such systems is difficult; many homeowners eventually turned off and drained their systems, then retrofitted to alternative heating means.

Three decades ago, the use of cross-linked polyethylene (PEX) and other polymer tubing became prevalent, solving corrosion and cracking problems. Based on this new and significantly more reliable technology, radiant floor heating experienced strong growth and acceptance. In some European countries, as much as 80% of all new home construction employs radiant floor heating.

Use of thin Portland cement or gypsum cement slabs on top of framed floor structures allowed its use in homes with framed floors, instead of concrete slab on grade construction. Sometimes tubing was merely stapled to the bottom of the subfloor in framed homes. While these framed floor solutions could produce effective systems, problems remained. Floor covering choices were often quite limited, response times were quite slow, and these systems asked general contractors to deviate significantly from conventional construction practice causing additional costs often not found in the radiant contractor's bid.

In 1998 Warmboard was introduced and the last lingering challenges of using radiant heat in framed floor construction were resolved. Finally there was a fast response system that was designed from the beginning to be an integral part of conventional framed floor construction, gave tremendous freedom in floor coverings choices and provided fast response, energy efficient radiant heat.